抽象
全固态锂硫电池 (ASSLSB) 具有高比能量、高安全性和低成本的承诺,是下一代储能的理想选择1,2,3,4,5.然而,由三相边界缓慢的固-固硫氧化还原反应 (SSSRR) 引起的速率性能差和循环寿命短的问题仍有待解决。在这里,我们展示了由硫硼硼磷酸锂碘化物 (LBPSI) 玻璃相固体电解质 (GSE) 实现的快速 SSSRR。在I之间的可逆氧化还原的基础上−和我2/我3−,固体电解质 (SE) 以及用作超离子导体,起到表面氧化还原介质的作用,促进固-固两相边界的缓慢反应,从而显着增加活性位点的密度。通过这种机制,ASSLSB 表现出超快充电能力,显示出 1,497 mAh g 的高比容量−1硫在 2C (30 °C) 下充电,同时仍保持 784 mAh g−1硫在 20C 时。值得注意的是,比容量为 432 mAh g−1硫是在 60 °C 下以 150C 的极端速率充电时实现的。 此外,该电池在 5C (25°C) 下在 25,000 次循环中表现出卓越的循环稳定性和 80.2% 的容量保持率。我们预计我们在氧化还原介导的 SSSRR 方面的工作将为开发高能量和安全的先进 ASSLSB 铺平道路。
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主要
开发全固态电池被认为对电动交通很重要,因为它们具有预期的高安全性和比能量6,7,8,9,10,11.基于层状金属氧化物 (LMO) 阴极的全固态电池很有吸引力12,13 元但改性活生物体与高电位 SE 的不可逆寄生反应以及富镍改性活生物体的化学机械降解阻碍了长期稳定性和速率能力14、15、16.原则上,具有高比能的 ASSLSB 可以消除其中一些挑战,因为中等电位不会导致 SE 的显着氧化1,2,3,4,5,充电时释放的任何活性氧都不会威胁到热安全17,18 元,因此有望获得更高的本质安全性。SE 的使用将进一步消除基于液体电解质的 Li-S 电池中存在的臭名昭著的多硫化物穿梭19.
然而,由于元素硫和锂的 SSSRR 都非常慢,ASSLSB 一直受到倍率性能和循环寿命不佳的困扰2S.由于这两种活性材料都是电子绝缘的,因此反应只能发生在 SE|活性材料|碳三相边界处,而三相边界都是固体。由于三相边界位点的密度通常远低于两相边界位点的密度,因此反应在空间上受到高度限制,对有效的固-固电荷转移构成挑战。通过在阴极中引入功能性添加剂,例如 Cu、LiVS,已经做出了显着的努力2和改性碳票价:20、21、22、23 元,但“全固体三相边界”挑战引起的不良动力学尚未完全解决(补充表 1)。此外,Li 的用途2S 作为活性材料可能会给电极制造带来技术挑战4、19、24.
在这项工作中,我们展示了使用 LBPSI GSE 实现的快速 SSSRR 和高循环稳定性。与使用额外的电子介导剂相比,电解质本身由氧化还原活性碘配制而成,因此它充当表面氧化还原介质,促进锂的氧化2S 粒子。SE 表面的碘阴离子可电化学氧化为 I2和我3−(表示为 I2/我3−) 在 SE|C 界,随后化学氧化 Li2S 接触。值得注意的是,这种基于 SE 表面的氧化还原介导过程使 SE|李2S 两相边界,否则处于非活动状态,但比所需的 SE|李2S|C 三相边界(图 D)。1a). 配制的电解质形成玻璃(而不是晶体)的趋势使可逆的碘氧化还原而不是持续的 SE 降解。使用这种 Redox 中介策略2,25,26,27,28,29,我们展示了具有出色充电能力(30 °C 时高达 35C)和循环稳定性的 ASSLSB。
a, ASSLSB 快速充电机制设计原理示意图。蓝色所示的氧化还原介导 SE 具有中等氧化还原活性并产生表面 I2/我3−在快速充电时介导硫反应;这使 SE|活性材料两相边界的反应恢复活力,否则该边界是非活性的,并且比传统要求的 SE|C|活性材料三相边界。b, 离子电导率随 P 的增加而变化2S5比率,定义为 n(P2S5)/n(P2S5+ B2S3).添加 P2S5时,离子电导率增加并在 n(P2S5)/n(P2S5+ B2S3) = 0.17,然后以更高的比率下降。c,−40 °C 和 60 °C 之间离子电导率的 Arrhenius 图以及相应的活化能 (E一个) 的三种电解质 n(P2S5)/n(P2S5+ B2S3) 比率为 0、0.17 和 0.29。d,e,三种电解质的局部结构分析11B (d) 及7Li (e) MAS NMR。d 中的球杆模型显示了不同的 [BS4] 协调环境;单桥 [BS4] 表示 [BS4] 彼此桥接,只有一个 B-S-B 键(形成链状结构),而多桥 [BS4] 表示每个 [BS4] 与几个 B-S-B 键桥接(形成网络结构)。B、S 和 Li 原子分别以蓝色、黄色和红色表示,实线代表 B 和 S 之间的共价键,虚线代表 S 和 Li 之间的离子键。0.17–0.50 ppm 处的 e 峰对应于由非桥接硫溶剂化的 Li,如 d 插图所示,而 −4.4 ppm 附近的峰对应于碘结合的 Li. a.u.,任意单位。++
GSE 的综合和表征
B2S3是一种优良的玻璃成型剂,有助于形成 Li 的 GSE2S-B2S3(参考。30),一种低质量密度的硫化物电解质家族。然而,原始的硫硼酸锂玻璃显示出非常低的离子电导率30.作为 P2S5也已知会形成硫化物玻璃31,我们提出了一类新的超离子 LBPSI GSE (Li2S-B2S3–P2S5–LiI) 通过调整两种玻璃成型剂的比例并使用 LiI 作为玻璃网络促进剂32.目标 GSE 是通过熔融淬火法获得的,X 射线衍射 (XRD) 分析证实了 LBPSI 的无定形状态(详见方法和扩展数据图 1)。电化学阻抗谱 (EIS) 测量表明,纯硫硼酸盐玻璃 (Li2S-B2S3–LiI,表示为 LBSI)32和硫代磷酸盐为主的玻璃 (P2S5/(P2S5+ B2S3) mol/mol 比为 0.80;n(P2S5)/n(P2S5+ B2S3)仅为 0.3200 和 0.0027 mS cm−1,而 n(P2S5)/n(P2S5+ B2S3) 的 0.11、0.17 和 0.29 表现出 1.6、2.4 和 1.8 mS cm 的高离子电导率−1,分别(图 D)。请注意,离子电导率随着 n(P2S5)/n(P2S5+ B2S3) 超过 0.29。与温度相关的离子电导率测量显示活化能 (E一个) 为 0.34、0.31 和 0.31 eV,对于 n(P2S5)/n(P2S5+ B2S3) 分别为 0、0.17 和 0.29 (图 D)。1c 和补充图1). 这些 GSE 都表现出 10 的可忽略不计的电子电导率−10–10−11S 厘米−1(扩展数据图 .1f-i),这有助于实现低自放电并可能抑制锂枝晶通过 SE 的渗透33.
拉曼光谱和11B,7Li 和31进行了 P 魔角旋转 (MAS) 核磁共振 (NMR) 波谱测量,以了解 P/B 比变化的离子电导率变化的起源,这与玻璃中的局部结构相关。如拉曼光谱所示(扩展数据图 .1b),方法是添加 P2S5其中 n(P2S5)/n(P2S5+ B2S3) = 0.17,则大 [B3S6] 和 [B2S5] 部分消失34,而 [BS4] 部分扩大34,以及拉曼敏感 [PS4] 波段34,35 元.这意味着添加二次玻璃成型剂 P2S5触发 [PS4],这反过来又会破坏大的多原子 [B3S6] 和 [B2S5] 组。[BS4] 部分带进一步被11B NMR 波谱(图 .1d)。其中 n(P2S5)/n(P2S5+ B2S3) = 0.17,则 0 ppm 附近的峰值对应于 [BS4] 部分偏移到更高的频率(从 -2.88 ppm 到 -1.01 ppm)36,表示从多桥接 [BS4] 更改为单桥 [BS4] (参考文献。36).这为 B-S 网络的碎片化和形成小的岛状局部结构提供了证据,这些结构的刚度较低,有利于高 Li 迁移率。此外,+7Li NMR 波谱表明,通过添加 P2S5其中 n(P2S5)/n(P2S5+ B2S3) = 0.17,对应于碘结合 Li (−4.4 ppm) 的峰+37大大减少,表明 Li/I 的包含性更好+−离子和分离度较低的离子对(图1e)。这被认为对于实现 I 的表面扩散很重要−在氧化还原介导循环期间38,如下所述。此外,对应于 Li 的肩峰通过非桥接硫(0.50 和 0.17 ppm)溶剂化+39在 0.22 ppm 处变为单个峰,表明屏蔽原子核较差40.有关进一步的讨论,我们建议读者参考 Extended Data Fig。1.
快速充电性能
在这里,我们首先使用碳/硫/LBPSI 复合阴极、LBPSI 隔膜和 In/InLi 箔阳极评估电池快速充电能力,从而研究 SSSRR 动力学。通过以各种 C 倍率和 30 °C 下 1C 的恒定放电速率对电池进行充电来评估快速充电性能。 LBPSI n(P2S5)/n(P2S5+ B2S3) = 0.17 表现出 1,497 mAh g 的高比容量−1(面容量,1.5 mAh cm−2) 以 2C 的充电速率并保持 784 mAh g−1以 20C 的 10 倍速率增加(图 D)。2a,b)。即使在 35C (59 mA cm−2),该电池仍可实现 447 mAh g 的高比容量−1.在所有充电速率下,电池都显示出明确的非电容电压曲线,显示出大大促进的 SSSRR 动力学(图 D)。2b 和扩展数据中的差分容量图请注意,在较高的充电速率下,由于 SE 中的离子传输有限以及与 In/InLi 对电极的反应过电位增加,电池显示出增加的欧姆极化(扩展数据图 D)。3a–f),因此需要应用更高电压的截止电压。值得注意的是,在这种速率下(以 20C 充电)的电池维持约 700 mAh g 的比容量−1在长期循环中没有明显的容量衰减(图 D)。相比之下,Li 的单元格5.5附言4.5Cl (四)1.5,尽管提供 1,417 mAh g 的良好比容量−1以 2C 充电时,仅保留 223 mAh g−1在 20C 时(图 D)。2a 和扩展数据图2d,e)。此外,LBPSI 显示的可逆氧化还原行为(扩展数据图 .2F-H)是调节 SSSRR 和快速充电能力的基础,如下所述。
a,使用不同 SE 在不同充电速率(标记)和 30 °C 时 1C 的恒定放电速率下对电池的性能进行评级。 细胞通过以 0.05-0.8C 的逐渐增加的速率充电 6 个周期,然后在 2C 下充电(硫负载:1.0 mg cm)进行活化过程−2).六个周期的电压曲线显示在扩展数据图 1 中。2b,c.b,不同充电速率下的电压曲线(由于研究的重点是阴极,为了在电池之间以及与文献中报道的其他电池进行比较,下面显示了关于 Li/Li 的阴极电位,假设 In/InLi 电位为 0.62 V,与 Li/Li)。c,使用 LBPSI 电解质的 ASSLSB 在 20C 充电速率下的循环稳定性。d,使用不同 SE 在不同充电速率(标记)和 60 °C 下 2C 的恒定放电速率下的电池性能速率。 细胞通过以 0.1-1C 的逐渐增加的速率充电几个循环(硫负载量:1.05 mg cm)进行活化过程++−2).e,f,60 °C 下充电速率为 5C 至 150C 的电压曲线,适用于具有 LBPSI (e) 和 Li 的 ASSLSB5.5附言4.5Cl (四)1.5电解质 (F)。
此外,采用 LBPSI 的电池在 60 °C 时表现出前所未有的快速充电能力。 在 2C 的固定放电速率下,它表现出 1,361 mAh g 的高比容量−1在 10C 下充电时,略微降至 1,162 和 815 mAh g−1分别在 20C 和 50C 时(图 D)。即使在 100C 和 150C 的极端充电倍率下,电池仍显示出 594 和 432 mAh g 的高比容量−1,分别具有明确的非电容行为(图 D)。2e 和扩展数据图以 100C 的速率充电的电池可以维持长时间循环,而不会出现明显的容量或电压衰减(扩展数据图 D)。3k,l)。相比之下,Li5.5附言4.5Cl (四)1.5仅显示 123 mAh g−1当以 50C 充电时,并以更高的速率提供接近零的容量(图 D)。2d,f 和扩展数据图因此,使用 LBPSI 的 ASSLSB 的快速充电性能远优于使用 Li 的 ASSLSB5.5附言4.5Cl (四)1.5.鉴于具有 LBPSI 和 Li 的阴极复合材料具有相似的离子/电子电导率和粒径5.5附言4.5Cl (四)1.5(扩展数据图 .4 和补充图2),这指向了基于 LBPSI 的阴极发生的另一种机制。
超快充电能力的由来
所展示的超快 SSSRR 与电极与绝缘活性材料固体反应缓慢的传统看法形成鲜明对比1、3、4.活性材料与 LBPSI 电解质或其氧化还原产物的相互作用应发挥重要作用。为了探索超快速率能力的起源,我们首先使用不含硫的 LBPSI-碳 (LBPSI-C) 复合材料作为阴极构建了一个电池。电极的比容量为 166 mAh g−1LBPSI第一次充电时,电位为 2.7 V(相对于 Li/Li),电流为 0.25 mA cm+−2并在以下放电中显示出可逆容量(图 D)。图3a 和扩展数据图5a,b)。可重现的电压曲线表明 LBPSI 表面存在高度可逆的氧化还原对(图 D)。图3a 和扩展数据图5a-c)。这对对的氧化还原电位 (2.7 V) 高于 S/Li 的氧化还原电位2S 电偶,原则上提供化学氧化 Li 的热力学驱动力2S.事实上,在 0.1C 的充电速率下,使用 LBPSI 电解质的硫阴极在 2.4 V 和 2.7 V 处显示出两个电压平台(扩展数据图 D)。5e,f),我们将其归于李2分别为 LBPSI 的 S 氧化和表面氧化。相比之下,李5.5附言4.5Cl (四)1.5–碳电池在第二次放电期间显示出较大的容量损失,表明对电解液造成了不可逆的损坏(图 D)。图 3b 和扩展数据图5d)。
a,b,含 LBPSI (a) 和 Li 的电池电压曲线5.5附言4.5Cl (四)1.5 (b) 作为电流密度为 0.25 mA cm 的活性材料−2(25 °C)。第一个循环涉及放电和充电,其中初始放电过程提供小容量。c,d,TOF-SIMS 分析结果显示 I2− (c) 和 I3− (d) LBPSI-C 电极在不同状态(原始、100% 荷电状态 (SOC) 和 100% 放电深度 (DOD))的片段。e,f,TOF-SIMS 分析结果显示 I2− (e) 和 I3− (f) 含 LBPSI 的硫阴极片段。箱形图的数据是从每个样品不同位置的五次测量中获得的。g,I 的 TOF-SIMS 3D 表示2−和我3−在完全带电的硫阴极中,通过深度剖面获得 LBPSI。h, 表面 I 的方案−–我2/我3−SSSRR 的氧化还原介导机制,涉及 I 的表面扩散和重新分布2和我−.i,对配置为 In/InLi|LPSCl |45 °C 时的 LBPSI–C。IQR,四分位距。
为了研究 LBPSI 在电池电荷上的表面氧化产物,我们进行了一系列光谱研究。首先,X 射线光电子能谱 (XPS) 数据(扩展数据图 D)。6) 显示 618.8 eV (3d 的 I 3d 双峰信号5/2energy) 表示原始 LBPSI,代表阴离子 I−在玻璃杯中41.将 LBPSI-C 电池充电至 3.2 V 时,观察到 I 3d 光谱总体上向更高的结合能转变,表明在 LBPSI 氧化时形成氧化碘物质(在 619.9 eV 时)42.此外,S 2p 光谱表明氧化硫物质 (S0) 充电43(扩展数据图 .6d). 硫阴离子的氧化之前也在 argyrodite SE 中观察到43,44 元因此,我们提出 LBPSI 和 Li 之间的主要区别5.5附言4.5Cl (四)1.5在于碘的可逆氧化/还原。
为了进一步研究碘物质的氧化,使用了飞行时间二次离子质谱法 (TOF-SIMS),因为它对低浓度高度敏感。在 LBPSI-C 充电时,我们观察到 I 在统计学上显着增加2和我3−物种,量化为 I 的强度2−和我3−用 I 的峰归一化−(假设大部分我−保持不变)(图3c,d 和补充图3).这确认了氧化产物为I2和我3−,其中 I2以更高的强度检测到。出院后,I2和我3−与带电状态相比,物质减少,表明可逆的氧化还原行为(图 D)。3c,d)。我们也观察到相同的趋势 I2和我3−在硫阴极中形成,带电时具有 LBPSI(图 D)。3e,f),从而清楚地证实了 I 的氧化还原−–我2/我3−确实发生在细胞中的 LBPSI 时。3D 深度剖析进一步显示 I 的均匀分布2−和我3−在带电阴极的某个区域上(图 D)。3g 和补充图3). I 的分数相对较低2和我3−与 I 的−意味着表面碘氧化的普遍存在(图 D)。我们还使用 LBPSI 对电池进行了差分电化学质谱 (DEMS) 测量。如图 1 所示。3i,在 2.11 V 与 In/InLi(即 2.73 V 与 Li/Li)的充电电压下,m/z = 127 的信号明显浪涌,这归因于 I,即 I 电离的片段++2.I 的形成2拉曼光谱也证实了这一点,其中充电至 3.2 V 的 LBPSI 在 100-200 cm 处显示宽带−1,对应于 I2和我3−(进一步讨论见 Extended Data Fig.6).
从这些观察中,我们提出 LBPSI 电解质基于 I 之间的可逆氧化还原充当 SSSRR 的表面氧化还原介质−(如 LBPSI 表面所示)和 I2/我3−在充电时,这激活了 SE|李2S 两相边界。提出充电反应并示意图如下:
I. LBPSI 的氧化(即 I−在表面上):
$${\rm{L}}{\rm{i}}{\rm{B}}{\rm{P}}{\rm{S}}{\rm{I}}-x{{\rm{e}}}^{-}\to (x/2){{{\rm{I}}}_{3}}^{-}+(3x/2){{\rm{L}}{\rm{i}}}^{+}+{{\rm{L}}{\rm{i}}}_{(1-3x/2)}{{\rm{B}}{\rm{P}}{\rm{S}}{\rm{我}}_{(1-3x/2)}$$
II. 介导的 Li 化学氧化2S(在两相边界处):
III. 锂的电化学氧化2S(在三相边界处):
具体来说,充电过程承受 I 的共氧化−(在 LBPSI 表面)和 Li2S.在高充电倍率下,电化学 Li2S 氧化会引起高过电位,即 I−在 LBPSI 的表面上 - 与碳接触时(在 SE|C 两相边界)—发生氧化,因为 LBPSI 本身是快锂导体(反应 1 和 2);因此,与碳接触的 LBPSI 颗粒表面富含氧化碘物质 I+2/我3−(示意图如图 2 所示。3h)。该反应方案由基于原位 EIS 测量的硫电池充电至 2.80 V 后对新界面的观察来支持(在扩展数据图 2 中讨论)。5g,h)。因为测得的 I 的氧化还原电位−–我2/我3−因为 LBPSI 高于 Li2S/S(2.7 V 与 2.4 V,如上所述),Li2原则上,S 可以被形成的 I 化学氧化2/我3−(反应 3 和 4)。该反应的发生通过混合 I 来验证2和李2S 在溶液和固态中,均产生 LiI 和 S 的混合物(扩展数据图 D)。7). 作为我2蒸汽压高,扩散非常快45,我们假设 I2可以通过气相沿孔隙和间隙快速扩散,并在相邻的 Li 处重新分布2S|SE 两相边界,在该边界处化学氧化 Li2S (图 1)3h)。碘接触实验证实了这一点,该实验显示了 I 的扩散2沿 SE 表面(扩展数据图 .7). 作为我3−是 I 的乘积2与 I 反应−在 SE 表面上,它也可能在这样的两相边界处形成。显然,李2S|SE 两相边界比 SE|李2S|C 三相边界。我们建议,重组后的 I−氧化还原后 mediation 可以重新分配给相邻的 Li2通过表面扩散的 S|SE 边界38或它与玻璃 SE 基质的动态复合,使其可以重复参与氧化还原介导以完成氧化还原介导循环(图 D)。3h)。尽管如此,Li 的电化学氧化2S 也仍然出现在三相边界处(反应 5)。
因此,LBPSI 不仅提供离子传导途径,还产生表面 I−–我2/我3−原位偶联作为氧化还原介质,促进固体到固体 Li2高充电速率下的 S 氧化(导致充电电位大于 2.7 V)。值得注意的是,这种效应不会在低充电率下发生,因为在低充电率下不会达到所需的电位,并且仅在充电时单向发生。放电时,LiI 可以在阴极中充当离子传导促进剂(扩展数据图 1)。8). 这种固体-固体表面氧化还原介导显然类似于在基于液体电解质的 Li-O 中观察到的2/S 电池票价:2,25,26,27,28,29,46,47 元,但在氧化还原介导的物质和电解质(全固体与固体-液体)的物理状态上有所不同。
因此,LBPSI 不仅提供离子传导途径,还产生表面 I−–I2/I3− 原位偶联作为氧化还原介质,促进高充电速率下固对固态 Li2S 氧化(导致电荷电位大于 2.7 V)。值得注意的是,这种效应不会在低充电率下发生,因为在低充电率下不会达到所需的电位,并且仅在充电时单向发生。放电时,LiI 可以在阴极中充当离子传导促进剂(扩展数据图 1)。8). 这种固-固表面氧化还原介导明显类似于在基于液体电解质的 Li-O2/S 电池中观察到的 2,25,26,27,28,29,46,47,但在氧化还原介导的物质和电解质的物理状态上有所不同(全固体与固体-液体)。
长期循环性能
接下来评估了基于 LBPSI GSE 的 ASSLSB(以等效速率放电/充电)的长期循环,面容量高达 8.9 mAh cm−2在 25 °C 下。 使用 Li 的单元5.5附言4.5Cl (四)1.5容量快速衰减,在 0.2C 下循环 100 次后仅保留 74.0%,表明反应不可逆(图 D)。图4a 和扩展数据图相比之下,基于 LBPSI 的电池可提供 1,375 mAh g 的高比容量−1,在 500 次循环后保留超过 91.7%,平均库仑效率接近一(图 D)。4a). 超过 500 次循环的电压曲线表明,仅发生轻微的化学/机械降解(扩展数据图 D)。这归因于 LBPSI 介导的反应的高可逆性,导致很少的 S/Li 死亡2S 和边缘 SE 降解,以及 GSE 的高延展性31在骑行过程中可以很好地容纳活性材料呼吸。
a, 基于 LBPSI 和 Li 的电池循环性能(充电容量)5.5附言4.5Cl (四)1.5在 0.2C 时(硫负荷:1.5 mg cm−2;实验实现的容量:2.1 mAh cm−2).b,基于 LBPSI 在 2C 下的细胞长期循环(硫负载量:1.1 mg cm)−2;实验实现的容量:1.2 mAh cm−2).细胞通过以 0.05-1C 的逐渐增加的速率循环数个周期来经历活化过程。c,基于 LBPSI 和 Li 的电池循环性能(充电容量)5.5附言4.5Cl (四)1.5在 5C 时(硫负载量:1.1 mg cm−2;实验实现的容量:0.91 mAh cm−2基于 LBPSI 的单元格)。通过以 0.05-4C 的逐渐增加的速率循环数个循环,使细胞经历活化过程。d,e,基于 LBPSI 的电池循环性能,硫负载量为 3.0 mg cm−2(实验实现的容量:3.0 mAh cm−2;301 毫安时 g−1阴极),在 0.2C (e) 时阴极中硫含量高达 45 wt%(硫负载量:1.9 mg cm)−2;实验实现的容量:2.0 mAh cm−2;472 毫安时 g−1阴极).库仑效率的计算方法是将放电容量除以同一周期的充电容量。
基于 LBPSI 的电池在 25 °C 下也显示出超稳定的循环性能(图 D)。4b-d)。在 2C 的速率下,该电池可提供 1,105 mAh g 的高比容量−1,在 5,000 次循环中具有 81.4% 的容量保持率(图 D)。4b 和扩展数据图值得注意的是,该电池的比容量为 823 mAh g−1在 5C (9.2 mA cm−2),在 25,000 次循环中具有 80.2% 的保留率(图 D)。4c 和扩展数据图相比之下,基于 Li 的单元格5.5附言4.5Cl (四)1.5显示容量快速衰减至 400 mAh g−1仅保留 81 mAh g−1在 5C 下循环 10,000 次后(图 D)。4c 和扩展数据图9e)。据我们所知,超过 25,000 次循环的长期稳定性在 Li-S 电池领域是前所未有的(补充表 1),因此突出了反应工程在 ASSLSB 开发中的潜力。具有 LBPSI 的电池的更多长期循环数据显示在扩展数据图 1 中。9 克,小时原位电池堆叠压力测量进一步表明,在 LBPSI 的情况下,微观体积变化具有更深的缓冲作用(扩展数据图 D)。9f)。
我们进一步表明,即使具有高硫负载的细胞在使用 LBPSI 时也表现出优异的性能。硫负荷量为 3.0 mg cm 的细胞−2提供 1,004 mAh g 的高比容量−1(3.0 毫安时厘米−2),速率为 1C (5.0 mA cm−2) 并保留 810 mAh g−11,000 次循环后(图 D)。4d 和扩展数据图此外,阴极中硫含量高达 45 wt% 的电池(35 wt% SE 和 20 wt% 碳)的比容量为 1,049 mAh g−1(2.0 毫安时厘米−2),并且在 200 次循环中显示出几乎可以忽略不计的衰落(图 D)。4e 和扩展数据图同样,硫负载量为 6.3 mg cm 的细胞−2显示 1,413 mAh g 的高比容量−1(8.9 毫安时厘米−2) 在 0.1C (1.1 mA cm−2),并在 100 次循环后保留 85.3%(扩展数据图 .10c,d)。
基于 LBPSI 的电池在 60 °C 的高温下也表现出良好的循环稳定性。 显而易见,图 1 中的单元格5a,b 在 1,070 mAh g 的比容量下稳定−1在 10C (17.4 mA cm−2),容量衰减小,电压曲线高度可重现,可运行约 3,500 次。在 15C (26.1 mA cm−2),该电池的比容量为 1,110 mAh g−1超过 1,000 次循环并保留 979 mAh g−110,000 次循环后(第 1,000 次循环时容量的 88.2%)(图 D)。5c 和扩展数据图10e,f)。相比之下,Li5.5附言4.5Cl (四)1.5迅速变质,经过几百次循环后容量几乎为零,表明在 60 °C 时发生了严重的、与电解质相关的寄生副反应(图 D)。5c 和扩展数据图10g)。
基于 LBPSI 的电池在 60 °C 的高温下也表现出良好的循环稳定性。显而易见,图 1 中的单元格5a,b 在 1,070 mAh g 的比容量下稳定−1在 10C (17.4 mA cm−2),容量衰减小,电压曲线高度可重现,可运行约 3,500 次。在 15C (26.1 mA cm-2),该电池的比容量在 1,000 次循环中为 1,110 mAh g-1,并在 10,000 次循环后保持 979 mAh g-1(第 1,000 次循环时容量的 88.2%)(图 D)。5c 和扩展数据图10e,f)。相比之下,含 Li5.5 的电池附言4.5Cl (四)1.5 的电池迅速恶化,经过数百次循环后容量几乎为零,表明在 60 °C 时存在严重的电解质相关寄生副反应(图 D)。5c 和扩展数据图10g)。
a,b,基于 LBPSI 电解质的电池在 10C 充电/放电速率下的循环性能和相应的电压曲线(硫负载:1.0 mg cm)−2;实验实现的容量:1.1 mAh cm−2).通过以 0.05-8C 的逐渐增加的速率循环数个循环,使细胞经历活化过程。c,电池在 15C 下的循环性能(充电容量)(硫负载量:1.0 mg cm)−2;实验实现的容量:约 1.1 mAh cm−2).通过以 0.05-10C 的逐渐增加的速率循环数个周期,使细胞经历活化过程。
a,b,基于 LBPSI 电解质的电池在 10C 充电/放电速率下的循环性能和相应的电压曲线(硫负载:1.0 mg cm)-2;实验实现的容量:1.1 mAh cm-2)。通过以 0.05-8C 的逐渐增加的速率循环数个循环,使细胞经历活化过程。c,电池在 15C 下的循环性能(充电容量)(硫负载:1.0 mg cm-2;实验实现的容量:约 1.1 mAh cm-2)。通过以 0.05-10C 的逐渐增加的速率循环数个周期,使细胞经历活化过程。
展望
ASSLSBs 的研究不仅面临一般的界面挑战(与所有全固态锂电池一样),还面临缓慢的 SSSRR 和较大的体积变化。我们的电化学数据表明,实际上可以通过设计要使用的 SE 使其包含氧化还原介导功能来促进阴极反应。这是通过设计一种本身具有氧化还原活性的电解质来实现的,因此能够介导锂的氧化2S 的 C 速率较高。该策略通过促进 SE|李2S 两相边界,可实现快速 SSSRR 反应和前所未有的快速充电能力。高 S/Li2S 转换效率可在 25,000 次循环中实现出色的循环稳定性。未来的工作应侧重于阴极结构工程,以提高密度和面负载,并将硫阴极与高面容量阳极相匹配,以加快 ASSLSB 的开发。总体而言,所提出的策略可能会解锁其他固态转化化学,到目前为止,由于动力学缓慢和可逆性差,这些化学仍然难以捉摸。
ASSLSBs 的研究不仅面临一般的界面挑战(与所有全固态锂电池一样),还面临缓慢的 SSSRR 和较大的体积变化。我们的电化学数据表明,实际上可以通过设计要使用的 SE 使其包含氧化还原介导功能来促进阴极反应。这是通过设计一种本身具有氧化还原活性的电解质来实现的,因此能够介导锂的氧化2S 的 C 速率较高。该策略通过促进 SE|李2S 两相边界,实现快速 SSSRR 反应和前所未有的快速充电能力。高 S/Li2S 转换效率可在 25,000 次循环中实现出色的循环稳定性。未来的工作应侧重于阴极结构工程,以提高密度和面负载,并将硫阴极与高面容量阳极相匹配,以加快 ASSLSB 的开发。总体而言,所提出的策略可能会解锁其他固态转化化学,到目前为止,由于动力学缓慢和可逆性差,这些化学仍然难以捉摸。
方法 方法
SE 合成 SE 合成
黎氏 GSE2S-B2S3–P2S5–LiI 族是通过熔融淬火法合成的。以摩尔 (n) 为单位的成分为 30Li2S-25B 系列2S3–45LiI–aP2S5,其中 a = 0(表示为 n(P2S5)/n(P2S5+ B2S3) = 0)、3(表示为 n(P2S5)/n(P2S5+ B2S3) = 0.11)、5(表示为 n(P2S5)/n(P2S5+ B2S3) = 0.17)、10(表示为 n(P2S5)/n(P2S5+ B2S3) = 0.29)、25 (表示为 n(P2S5)/n(P2S5+ B2S3) = 0.50)、50(表示为 n(P2S5)/n(P2S5+ B2S3) = 0.67)、75(表示为 n(P2S5)/n(P2S5+ B2S3) = 0.75) 和 100 (表示为 n(P2S5)/n(P2S5+ B2S3) = 0.80) (图 .1b). Li 的化学计量量2S(Alfa Aesar,99.9%)、B(Macklin,99.9%)、硫(Alfa Aesar,99%)、LiI(Ourchem,99.9%)和 P2S5(Innochem,99%)在填充 Ar 的手套箱中使用玛瑙砂浆一起研磨 (p(O2)/p < 0.01 ppm,p(H2O)/p < 0.01 ppm)。将前驱体混合物造粒并放入玻璃状碳坩埚中,然后放置在石英管内。将石英管在真空下密封,置于马弗炉内,并在 500 °C 的温度下保持 10 小时。之后,将温度升至 800 °C,再持续 20 小时。最后,通过在冰水中淬火,熔融材料迅速冷却,从而形成玻璃。玻璃相电解质被粉碎并研磨成粉末,用于进一步表征和电池组装。
通过熔融淬火法合成了 Li 2S-B2S 3-P2S5-LiI 家族的 GSE。 以摩尔 (n) 为单位的成分为 30Li2S–25B2S3–45LiI–aP2S5,其中 a = 0(表示为 n(P2S5)/n(P2S5 + B2S3) = 0),3(表示为 n(P2S5)/n(P2S5 + B2S3) = 0.11), 5 (表示为 n(P2S5)/n(P2S5 + B2S3) = 0.17), 10 (表示为 n(P2S5)/n(P2S5 + B2S3) = 0.29)、25(表示为 n(P2S5)/n(P2S5 + B2S3) = 0.50)、50(表示为 n(P2S5)/n(P2S5 + B2S3) = 0.67)、75(表示为 n(P2S5)/n(P2S5 + B2S3) = 0.75)和 100(表示为 n(P2S5)/n(P2S5 + B2S3) = 0.80) (图 . 1b).Li2S(Alfa Aesar,99.9%)、B(Macklin,99.9%)、硫(Alfa Aesar,99%)、LiI(Ourchem,99.9%)和 P2S5(Innochem,99%)在填充 Ar 的手套箱中使用玛瑙砂浆一起研磨(p(O2)/p < 0.01 ppm,p(H 2O)/p < 0.01 ppm)。将前驱体混合物造粒并放入玻璃状碳坩埚中,然后放置在石英管内。将石英管在真空下密封,置于马弗炉内,并在 500 °C 的温度下保持 10 小时。之后,将温度升至 800 °C,再持续 20 小时。最后,通过在冰水中淬火,熔融材料迅速冷却,从而形成玻璃。玻璃相电解质被粉碎并研磨成粉末,用于进一步表征和电池组装。
李5.5附言4.5Cl (四)1.5电解质是通过固态路线通过 Ar 保护球磨和随后的烧结合成的。Li 的化学计量量2S(阿尔法埃撒,99.9%),P2S5(Innochem,99%)和 LiCl(Alfa Aesar,99%)在行星式球磨机(MSK-SFM-1,Kejing)中以 500 rpm 的速度用氧化锆球磨 10 h,氧化锆球料比为 20:1。然后,将球磨材料造粒并放置在石英管内。将石英管真空密封,在 500 °C 下烧结 15 h,然后自然冷却至室温。合成的样品在使用前被研磨成粉末。离子电导率 (25 °C) 约为 7.5 mS cm−1.
Li5.5PS4.5Cl1.5 电解质是通过 Ar 保护球磨和随后的烧结通过固态路线合成的。将 Li2S(Alfa Aesar,99.9%)、P2S5(Innochem,99%)和 LiCl(Alfa Aesar,99%)在行星球磨机(MSK-SFM-1,客晶)中以 500 rpm 的磁磨速度球磨 10 h,用氧化锆球,氧化锆与材料重量比为 20:1。然后,将球磨材料造粒并放置在石英管内。将石英管真空密封,在 500 °C 下烧结 15 h,然后自然冷却至室温。合成的样品在使用前被研磨成粉末。离子电导率 (25 °C) 约为 7.5 mS cm-1。
李3附言4和 70Li3附言4·30LiI电解液通过固态路线,通过Ar保护球磨和随后的烧结合成。Li 的化学计量量2S(阿尔法埃撒,99.9%)和 P2S5(Innochem,99%)(和 LiI (Ourchem, 99.9%) 用于 70Li3附言4·30LiI) 以 500 rpm 的转速进行球磨 10 h。将研磨后的产品在真空下密封在石英管中,并在 250 °C 下烧结 3 h,然后自然冷却至室温。
材料表征
用于测量的样品是在充满 Ar 的手套箱中制备的。使用带有 Cu K 的理学 MiniFlex600 X 射线衍射仪对合成的电解质粉末进行 XRD 分析α辐射 (λ = 1.5418 Å)。将粉末置于样品架中,并用 Kapton 薄膜密封,以避免与空气和湿气接触。在 10–70° 的 2θ 范围内以 0.01° 的步宽收集衍射数据。在雷尼绍显微拉曼光谱仪上使用 532 nm 激光器记录拉曼光谱。该系统由 Si 的拉曼峰校准。将样品置于样品架中,并用 Kapton 薄膜密封,以避免与空气和湿气接触。带电阴极从 In/InLi|LBPSI|用于非原位拉曼研究的 LBPSI-C 电解槽。(I2+LiI)-BM (I2/LiI 研磨产品)用于拉曼测量,通过球磨化学计量量的 LiI(Ourchem,99.9%)和 I 获得2(阿拉丁,99.9%),摩尔比为 1:1,500 rpm 持续 10 小时。固体 NMR 测量在 600 MHz 的 Bruker Avance III HD 波谱仪上进行,用于7李11B 和31P. XPS 测量是使用 Al K 的 AXIS Supra 仪器 (Kratos Analytical) 进行的α(1,486.7 eV) 石英单色器源。对于非原位 XPS 研究,In/InLi|LBPSI|将 LBPSI-C 电池(充电/放电前后)从电池中取出。所有样品均使用惰性气体样品转移装置转移,以避免空气和湿气暴露。使用 CasaXPS 软件处理光谱,其中所有数据都根据 284.6 eV 的不定碳信号进行校准。使用场发射扫描电子显微镜 (Regulus8220, Hitachi) 获得电解质和硫电极的形态学和相应的能量色散 X 射线光谱 (EDX) 映射。
非原位 XANES 测量
S K-edge X 射线吸收近边缘结构 (XANES) 实验在中国北京同步辐射装置 (BSRF) 的 4B7A 光束线上使用 Si (111) 晶体单色器进行。XANES 数据以荧光模式收集。电极和参考物质用 Kapton 薄膜密封,以避免与空气和湿气接触。使用 Athena 软件校准、对齐和归一化 XANES 光谱48.
TOF-SIMS analyses
TOF-SIMS surface characterization was done on a M6 Hybrid SIMS instrument (IONTOF). Cycled sulfur cathodes fitted with LBPSI electrolyte and the cathode using LBPSI as the active material without sulfur were compared with pristine (uncycled) cathodes. Surface measurements were performed in spectrometry mode (mass resolution m/Δm ≥ 7,000@m/z = 31.97 (S−)). Using Bi3+ ions with an energy of 30 keV as primary ion species (PI current = 0.03 pA), areas of 100 × 100 μm2 were analysed with 128 × 128 pixels in sawtooth raster mode. After reaching a primary ion dose of 1.0 × 1011 ions per cm2 (dose density limit), the measurements were stopped to achieve comparable conditions. Five mass spectra for each sample were recorded in negative ion mode at different locations on the surface. For the depth profiling of the fully charged sulfur cathode fitted with LBPSI, 200 analysis scans were recorded with the above conditions and primary ion doses of 0.33 × 1011 ions per cm2 per scan and 1.467 s sputter steps (with a 10 keV Ar2000+ gas cluster ion beam, sputter current = 10 nA) in between. All samples were attached to non-conductive adhesive tape and transferred to the SIMS instrument using the Leica EM VCT500 shuttle (Leica Microsystems). Charge compensation during the measurements was achieved with an electron flood gun. Data evaluation was carried out with SurfaceLab 7.3 software (IONTOF).
Electrochemical measurements
The ionic conductivity was measured by EIS using a BioLogic SP-200 electrochemical working station, with an amplitude of 10 mV in the frequency range 7 MHz to 100 mHz. The SE powder was placed into a PEEK cylinder with a diameter of 10 mm. Two Ti rods were placed on opposite sides of the PEEK cylinder to create a pellet by cold pressing at 320 MPa for 3 min. Then, the cell was placed into a custom-made stainless-steel casing with a pressure of about 84 MPa for the EIS measurements. To obtain the activation energy Ea, the cell was placed in an oven and the impedance was measured at temperatures ranging from −40 °C to 60 °C. Ea was evaluated using the equation σT = σ0exp(−Ea/kBT), in which σ is the ionic conductivity, σ0 is the pre-exponential factor, T is the absolute temperature and kB represents the Boltzmann constant. The electronic conductivity of SEs and different sulfur cathodes was obtained by measuring the electron resistance with an ion-blocking cell configuration of Ti|sample|Ti through the direct current (DC) polarization method. A constant voltage was set to 1 V and held for 20 h to ensure that the cell polarization reaches a stationary state for the Ti|SE|Ti configuration. For the Ti|sulfur electrode|Ti configuration, a constant voltage of 0.1 V was applied and held for 5 h. The resistance was calculated by Ohm’s law. The ionic conductivity of the sulfur cathodes was obtained by measuring the total ionic resistance with an electron-blocking configuration of Ti|Cu|In/InLi|SE|sulfur electrode|SE|In/InLi|Cu|Ti (ref. 21). A constant voltage of 0.5 V was applied for 2 h to allow the cell polarization to reach equilibrium. Note that the resistance values here include the resistance from the sulfur electrode, the SE layer and the In/InLi electrode. To subtract the resistance contributions from the SE and In/InLi layers, the impedance of a symmetric cell Ti|Cu|In/InLi|SE|In/InLi|Cu|Ti was measured and the impedance data were fitted with an equivalent circuit model. The true ionic resistance of the sulfur electrode with the electron-blocking condition is obtained after subtracting the contributions of SE and In/InLi electrode. Cyclic voltammetry (CV) measurements of the cell In/InLi|LBPSI|LBPSI–C were conducted at room temperature with a Gamry Interface 1010E electrochemical workstation at a scan rate of 0.1 mV s−1.
EIS measurements as function of state of charge
In situ EIS measurements were performed on the ASSLSB fitted with LBPSI electrolyte at different states of charge/discharge (sulfur loading of 1.1 mg cm−2) at room temperature. Specifically, a current pulse of 0.1C was applied to the specified voltage, followed by 15 min open-circuit rest, after which the EIS was measured; this was repeated until the completion of discharge/charge. The frequency was scanned over the range spanning 7 MHz to 100 mHz with an alternating voltage amplitude of 10 mV.
All-solid-state cell fabrication
The sulfur powder and Ketjen Black (KB) were mixed (75:25, wt:wt) by grinding and then thermally annealed at 155 °C for 10 h to obtain the S/KB composite. The cathodes for ASSLSBs with a total sulfur fraction of 30 wt% were then prepared by ball-milling the S/KB composite, Super P carbon and LBPSI SE with a weight ratio of 4:1:5 and the cathodes with a total sulfur fraction of 45 wt% were prepared with a S/KB composite (75:25, wt:wt), Super P and LBPSI weight ratio of 6:0.5:3.5. For assembling the ASSLSB, approximately 80 mg of LBPSI powder was placed into a PEEK cylinder and pressed at 128 MPa for 1 min (10 mm diameter) as the SE layer and then the cathode composite with targeted areal loading was evenly spread and pressed under 320 MPa for 3 min. Onto the other side of the pellet, a thin indium foil (9 mm diameter, 99.99%, about 0.2 mm thickness) was attached and then a thin Li foil (7 mm diameter, about 0.1 mm thickness) was placed over the indium foil. The cell was placed into a custom-made stainless-steel casing with a stacking pressure of about 64 MPa. The assembly of ASSLSBs using Li5.5PS4.5Cl1.5 electrolyte remained the same, except the replacement of the LBPSI by Li5.5PS4.5Cl1.5 in the cathode and the electrolyte layer (that is, the cathode with a S/KB composite:Super P carbon:Li5.5PS4.5Cl1.5 weight ratio of 4:1:5). The assembly of ASSLSBs using Li3PS4 or 70Li3PS4·30LiI electrolyte remained the same. The cell was placed in an oven at specified temperatures during cycling. The cells were subjected to an activation process by charging at progressively increasing rates for several cycles before rate-capability testing to facilitate particle rearrangement for better solid–solid contact within the cathode. The specific capacity of the ASSLSB was calculated on the basis of the mass of sulfur. Current densities across the cells were calculated according to 1C = 1,672 mA g−1. The areal current density for a cell with a sulfur loading of 1.05 mg cm−2 at the cathode (the ASSLSB fitted with LBPSI electrolyte in Fig. 2e) is 8.8, 17.6, 35.1, 52.7, 87.8, 140.4, 175.6, 210.7 and 263.3 mA cm−2 for the rates of 5C, 10C, 20C, 30C, 50C, 80C, 100C, 120C and 150C, respectively. For the cells using the SE as the active material in the cathode (no sulfur contained), the SE–C cathode powder was prepared by ball-milling 80 wt% of LBPSI or Li5.5PS4.5Cl1.5 and 20 wt% Super P carbon. For preparation of the In/InLi symmetric cells, roughly 120 mg of LBPSI powder was placed into a PEEK cylinder and pressed at 128 MPa for 1 min (10 mm diameter) as the SE layer, and then on each side of the electrolyte a thin indium foil (9 mm diameter, 99.99%, about 0.2 mm thickness) and a thin Li foil (7 mm diameter, about 0.1 mm thickness) were attached. The symmetric cell was placed into a custom-made stainless-steel casing with a stacking pressure of approximately 21 MPa. The customized three-electrode cell was configured as In/InLi|LBPSI|S using In/InLi anode, sulfur cathode and a Li wire as the reference electrode. A total of about 150 mg LBPSI electrolyte was used. The Li wire reference electrode was buried in the electrolyte separator with moderate pressing to maintain the integrity of the electrolyte separator and prevent premature short-circuiting of the cell. To better isolate the polarization from the In/InLi negative electrode (that is, reduce the impact of electrolyte separator ohmic polarization on the potential of the LiIn electrode), the Li reference electrode was positioned close to the In/InLi anode.
Operando pressure measurements
The dynamic evolution of operation pressure for the two all-solid-state Li–S cells prepared with LBPSI and Li5.5PS4.5Cl1.5 electrolyte was measured by an in-house-made solid-state module configured with a high-precision pressure meter. The cells were assembled using sulfur cathodes (sulfur loading of about 1 mg cm−2) and In/InLi counter electrode with the respective SEs. The cells were discharged and charged with a rate of 0.2C at 30 °C.
DEMS measurements
For DEMS measurement, the cell preparation was similar to the electrochemical testing mentioned above. First, 100 mg of Li6PS5Cl (denoted as LPSCl, NEI Corporation) was densified under 0.5 tons to form the separator layer in a customized PEEK ring designed for the set-up. The LBPSI–C (Super P) cathode composite (weight ratio 70:30) with a mass loading of approximately 10 mg was placed on one side of the separator layer. An aluminium mesh (8 mm in diameter) was placed on top and all components were pressed together at 435 MPa to prepare the working electrode. The counter electrode, an In/InLi electrode, was assembled by stacking indium foil (8 mm diameter, 100 µm thickness, Thermo Scientific) and lithium foil (6 mm diameter, 50 µm thickness, Albemarle Germany) sequentially underneath the separator layer. The pellet contained in the PEEK ring was then transferred into the DEMS set-up. Before placing the current collectors, a stainless-steel mesh (9 mm diameter) was positioned on top of the cathode layer to enhance the electronic conductivity. After closing the cell with the current collectors, electrochemical cycling was conducted using a BioLogic VSP-300 potentiostat. The potential range was set between 0.8 and 2.4 V versus In/InLi (equivalent to 1.42–3.02 V versus Li/Li) and galvanostatic cycling was performed at a 0.05C rate. Before cycling, a 3-h rest period was implemented to stabilize the cell and ensure proper background for the mass spectrometer. The testing temperature was maintained at 45 °C, with helium as the carrier gas flowing through the DEMS cell at a controlled rate of 2.5 ml min+−1. For further gas analysis, an OmniStar GSD 320 O2 (Pfeiffer Vacuum) was used. A more detailed description of the DEMS set-up and measurement principles can be found in the literature49,50. Owing to weak signal intensity, the recorded signal current was smoothed within a 30–40-data-point range using a Savitzky–Golay filter (polynomial of the second order), followed by baseline correction.
Data availability
The datasets analysed and generated during the course of this study are included in the paper and the Supplementary information.
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Acknowledgements
This work was supported by the National Key R&D Program of China (grant no. 2021YFB2500200), the National Natural Science Foundation of China (NSFC) (grant nos. 92372115, 22075002). We are also grateful for the support from the Beijing Natural Science Foundation (no. Z220020) and NSFC (52103329, 22409006 and 52203347). We acknowledge the financing from BMBF (Bundesministerium für Bildung und Forschung, Germany) within the project SOLIS (03XP0395D). We thank the beamline station 4B7A at the Beijing Synchrotron Radiation Facility (BSRF) for the XANES measurements. We appreciate T. L. Song (Experimental Center of Advanced Materials, School of Materials Science & Engineering, Beijing Institute of Technology) for the contribution to the discussion of the TOF-SIMS study.
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Extended data figures and tables
Extended Data Fig. 1 Structural characterizations and physicochemical properties of the LBPSI GSEs (the ratio x is defined as n(P2S5)/n(P2S5 + B2S3)).
a, XRD patterns for the LBPSI electrolytes with x of 0, 0.11, 0.17, 0.29, 0.50, 0.67, 0.75 and 0.80. b, Raman spectra of LBPSI electrolytes with x from 0 to 0.80. c, Enlarged view focused on the [PmSn] clusters. d, Schematic drawing of the clusters with their characteristic Raman shift. e, 31P MAS NMR spectra of LBPSI electrolytes with x of 0.17 and 0.29. f–h, DC polarization curves with an ion-blocking cell configuration of Ti|electrolyte|Ti for the three LBPSI electrolytes with x of 0 (f), 0.17 (g) and 0.29 (h). The thicknesses of the pellets during measurement for the three electrolytes are 0.028 cm, 0.022 cm and 0.023 cm, respectively. The measurements were conducted at 25 °C. i, The trend of electron conductivities obtained from DC polarization curves and the corresponding Ea values. The electronic conductivities for the three LBPSI electrolytes with x of 0, 0.17 and 0.29 are 6.4 × 10−10 S cm−1, 2.8 × 10−11 S cm−1 and 2.8 × 10−10 S cm−1, respectively. It is clear that, by fine-tuning the P/B ratio in the sulfide glass, the electronic conductivity of the electrolytes can be reduced. The values are much lower than the typical electron conductivity of argyrodite Li6PS5Cl and Li5.5PS4.5Cl1.5 (typically measured to be 10−8–10−9 S cm−1)51,52, which may lead to low self-discharge in a cell. Discussions on the evolution of local clustering structures: on the basis of the XRD patterns (a), for the P2S5-free electrolyte (x = 0), a crystalline LiI phase is present, indicating that the LBSI glass framework cannot fully include the amount of LiI added, which leads to the precipitation of crystalline-phase LiI on quenching. With the addition of P2S5, the fraction of the crystalline phase of LiI markedly decreases and is barely observed at x = 0.17, indicating that, with a small amount of P2S5, the glass structure can better dissolve and integrate the LiI. The generated I− in the glass structure can therefore contribute to a weaker coulombic attraction for Li. However, at high P+2S5/(P2S5 + B2S3) ratios of x = 0.75 and 0.80, the peak of crystalline LiI gradually appears again, suggesting that excessive P2S5 counteracts on the integration of LiI and would impede the Li diffusion. The Raman spectrum of P+2S5-free electrolyte (x = 0) (b,c) shows the presence of only the [BmSn] group: the bands around 394 cm−1 and 433 cm−1 correspond to the B–S breathing mode of [BS3] groups34; the bands around 312 cm−1, 497 cm−1 and 763 cm−1 correspond to the vibrations of metathioborate [B3S6], thiopyroborate [B2S5] and [BS4] groups, respectively34,53. With x increased to 0.11 and 0.17, a strong Raman peak corresponding to the [PS4] group appears at 420 cm−1 (ref. 35), along with decrease of the [BmSn] peaks. Notably, at x = 0.29, two more peaks appear at 386 cm−1 and 407 cm−1, corresponding to the polyanionic groups of [P2S6]hypo and [P2S7], respectively34,35. Further, when x = 0.50, the Raman peak corresponding to [PS4] greatly fades, whereas those of [P2S6]hypo and [P2S7] groups are more pronounced, along with the appearance of a new peak at 582 cm−1 ascribed to [P2S6]hypo (refs. 54,55). Here the two peaks at 386 cm−1 and 582 cm−1 represent the symmetric and asymmetric stretching modes of the [P2S6]hypo group, respectively (d)54. As x further increases to 0.67, the [PS4] peak is no longer observed and a new peak appears at 425 cm−1, along with two subtle peaks at 315 cm−1 and 368 cm−1, corresponding to the [P2S6]meta group54,55. Further increasing the fraction of P2S5 to x = 0.75 and 0.80 leads to a much higher intensity of the [P2S7] peak, along with the peaks of [P2S6]meta and [P2S6]hypo. On the basis of these results, we can clearly observe two transitions of the local structures in the LBPSI electrolytes as x increases: (1) the appearance of the [PS4] group at x = 0.11; (2) the gradual disappearance of the [PS4] group, along with the dominance of the [P2S6] and [P2S7] groups at x = 0.50. By associating the local structural changes with the evolution of ionic conductivity (Fig. 1b), we can draw the following conclusions: at x = 0.11, the appearance of the [PS4] group substantially enhances the ionic conductivity, accounting for the high conductivity of more than 1 mS cm−1 at x = 0.11, 0.17 and 0.29. We believe that the [PS4] group promotes disruption of the large B–S network and formation of island-like structures, thereby enhancing the Li ion transport. The fragmentation is probably because of the different coordination preference of P (fourfold coordinated) and B (threefold coordinated), that is, the incorporation of P thermodynamically breaks the threefold coordinated B–S network. As x increases to 0.50, the appearance and dominance of [P+2S6] and [P2S7] polyanions decreases the ionic conductivity, which ultimately reduces to 10−3 mS cm−1 at x = 0.80, which is probably because of the highly charged polyanions exhibiting higher coulombic attraction for Li ions than the [PS+4] group35. Further, as shown in 31P MAS NMR spectra (e), the resonances around 83 ppm, 99 ppm and 108 ppm can be ascribed to the [PS4], [P2S7] and [P2S6] groups, respectively34. It is clear that the resonance of [PS4] appears in the electrolytes with x = 0.17 and 0.29. Further, the resonance of polyanionic [P2S7] and [P2S6] groups appear in the electrolyte with x = 0.29 (and not in the one with 0.17), which is in accordance with the Raman results. Altogether, in LBPSI, we find evidence for a more fragmented network (which should provide more free volume) and effective inclusion of I−, which results in higher ionic conductivity and easier breaking of the bond between Li and the anionic framework ligands at the electrode–electrolyte interface.+
Extended Data Fig. 2 Detailed electrochemical performance data for the evaluation of fast-charging ASSLSBs.
a, Differential capacity (dQ/dV) plots of the ASSLSB fitted with LBPSI with varied charging rates from 2C to 35C and a fixed discharging rate of 1C at 30 °C (voltage profiles shown in Fig. 2b; sulfur loading: 1.0 mg cm−2). b,c, The discharge–charge voltage profiles at varied rates for the first several activation cycles (shown in Fig. 2a) of the cells with LBPSI (b) and Li5.5PS4.5Cl1.5 (c). d,e, The discharge–charge voltage profiles of the ASSLSB fitted with the Li5.5PS4.5Cl1.5 electrolyte with charging rates from 2C to 35C and a fixed discharging rate of 1C at 30 °C (d) and the corresponding differential capacity (dQ/dV) plots (e) (sulfur loading: 1.0 mg cm−2). On the basis of the dQ/dV plots, we can observe that charging and discharging of the cell fitted with LBPSI exhibits distinct redox peaks when charged at 2C to 35C rates, indicating faradaic processes; in contrast, the cell fitted with Li5.5PS4.5Cl1.5 exhibits very small oxidation peaks when charged at rates exceeding 15C. f–h, The specific capacity (f), discharge–charge voltage profiles (g) and dQ/dV plots (h) of the cell using LBPSI as the active material (containing no sulfur in cathode; mass based on LBPSI), measured at the same areal current density as that for the ASSLSB in Fig. 2a (discharge current density is 1.7 mA cm−2). The loading of LBPSI is 1.9 mg cm−2, close to the amount of LBPSI used in the cathode of an ASSLSB. In the dQ/dV plots, we can observe distinct oxidation and reduction peaks owing to the redox behaviour of the LBPSI electrolyte itself. It should be noted that a small but constant fraction (7.8–8.9%) of the capacity comes from the fully reversible redox behaviour of the LBPSI electrolyte at all investigated rates, as quantified by the cell using LBPSI as the only active material. i, The dQ/dV plots of the ASSLSB fitted with LBPSI at 60 °C, with varied charging rates from 5C to 150C and a fixed discharging rate of 2C (sulfur loading: 1.05 mg cm−2). j, The dQ/dV plots of the ASSLSB fitted with Li5.5PS4.5Cl1.5 at charging rates from 5C to 150C and a fixed discharging rate of 2C at 60 °C. k,l, The discharge–charge voltage profiles (k) and dQ/dV plots (l) of the cell with LBPSI as the active material (containing no sulfur in cathode) at 60 °C (discharging current density is 3.5 mA cm−2; the loading of LBPSI is 1.9 mg cm−2).
Extended Data Fig. 3 Galvanostatic cycling of the In/InLi|LBPSI|In/InLi symmetric cell, the three-electrode sulfur-containing cell and long-term cycling of the ASSLSB at extreme charging rates.
a,b, The galvanostatic cycling of the In/InLi|LBPSI|In/InLi symmetric cell (In/InLi foil as both electrodes) with current increasing from 0.26 mA cm−2 to 31.8 mA cm−2 at 25 °C (the Li plating/stripping time is 30 min for measurements with current density ≤ 3.8 mA cm−2 and 5 min for those with current density ≥ 6.4 mA cm−2) and enlarged section at high currents (reaching the voltage limit) (b). The symmetric cell can indeed operate at higher currents without soft or hard short-circuit at the areal capacity used, but in fact suffers from much greater overpotential than at low currents; this indicates that the In/InLi electrode shows limited reaction kinetics. This result offers some qualitative hints on the overall poor reaction kinetics for In/InLi electrodes. Such a high overpotential at the anode, along with the ohmic resistance from the SE, contributes to the high overpotential of full cells at high currents. c–f, Three-electrode cell measurement to examine the origin of the high overpotential of full cells at high currents. c, The scheme of the three-electrode cell, with a thin Li wire placed in the electrolyte layer close to the In/InLi counter electrode as a reference electrode. d–f, Discharge–charge voltage profiles at the current density of 0.08 mA cm−2 (d), 8.3 mA cm−2 (e) and 15.0 mA cm−2 (f) (sulfur loading of 1.0 mg cm−2; 25 °C). At a very low current density of 0.08 mA cm−2, the potential of the In/InLi electrode stabilizes at around 0.61 V. As the current density increases to 8.3 mA cm−2, the potential of the In/InLi electrode increases to about 0.75 V (on discharge) and reduces to about 0.46 V (on charge), resulting in a discharging overpotential of 0.14 V and charging overpotential of 0.15 V. On further increasing of the current to 15.0 mA cm−2, the potential of the In/InLi electrode increases to about 0.90 V (on discharge) and the potential decreases to about 0.31 V (on charge), resulting in a discharging overpotential of 0.29 V and charging overpotential of 0.30 V. Therefore, the reaction overpotential of the In/InLi electrode is high and increases greatly with the current density. Furthermore, there is a large increase of the ohmic resistance when the current is increased from 0.08 mA cm−2 to 8.3 mA cm−2. The ohmic resistance is qualitatively recognized by the abrupt voltage change (IR drop) on supplying of the charging/discharging currents. The increased ohmic resistance is the result of the thick layer of the electrolyte separator between the sulfur working electrode and the Li reference electrode, and the moderate ionic conductivity of the SE (2.4 mS cm−1). The high overpotential of the cell at high charging rates is largely because of the In/InLi anode and IR ohmic polarization56. g–j, The actual discharge–charge voltage profiles by using the potential versus In/InLi counter electrode of the ASSLSBs fitted with the LBPSI and Li5.5PS4.5Cl1.5 electrolyte at different current densities at 30 °C (g,h) and 60 °C (i,j). k,l, Cycling performance (k) and discharge–charge voltage profiles (l) of ASSLSB fitted with LBPSI electrolyte at a charging rate of 100C and a discharging rate of 2C at 60 °C. The cell was subjected to an activation process by cycling at 1–80C (charging rates) for several cycles. The cell sustains 5,000 cycles with a capacity retention greater than 80.4% (sulfur loading: 1.0 mg cm−2). It is clear that the cell experienced marginal voltage degradation over the cycling. The fluctuation in Coulomb efficiency is because of the limited resolution for data acquisition from the equipment with such a short duration of charging.
Extended Data Fig. 4 The electronic and ionic conductivity of sulfur electrodes prepared with LBPSI-0.17, LBPSI-0.29 and Li5.5PS4.5Cl1.5 and the morphological characterization of the electrolytes.
a, DC polarization curves of sulfur electrodes with an ion-blocking configuration of Ti|sulfur electrode|Ti. b–d, DC polarization curves of sulfur electrodes with an electron-blocking configuration of Ti|Cu|In/InLi|SE|sulfur electrode|SE|In/InLi|Cu|Ti. e, Nyquist plot of the symmetric cell of In/InLi|SE|In/InLi. f–k, Scanning electron microscopy (SEM) images (f–h) and corresponding particle size distributions (derived from the SEM imaging by statistical analysis; scale bars, 10 μm) (i–k) of LBPSI-0.17 (f,i), LBPSI-0.29 (g,j) and Li5.5PS4.5Cl1.5 (h,k). The electronic conductivity of the sulfur cathodes was obtained by measuring the electronic resistance with an ion-blocking cell configuration of Ti|sulfur electrode|Ti (a). The room-temperature electronic conductivities for the three sulfur cathodes prepared with LBPSI-0.17, LBPSI-0.29 and Li5.5PS4.5Cl1.5 is 0.031 S cm−1, 0.022 S cm−1 and 0.042 S cm−1, respectively. The ionic conductivities of the sulfur cathodes was obtained by measuring the total ionic resistance with an electron-blocking configuration of Ti|Cu| In/InLi|SE|sulfur electrode|SE|In/InLi|Cu|Ti (ref. 21) (b–d). The contributions of the SE and In/InLi electrode are measured to be 23 Ω and 0.9 Ω with the equivalent circuit fitting of the symmetric cell Ti|Cu|In/InLi|SE|In/InLi|Cu|Ti (e). The room-temperature ionic conductivity for the three sulfur cathodes prepared with LBPSI-0.17, LBPSI-0.29 and Li5.5PS4.5Cl1.5 after subtracting the contributions of SE and In/InLi electrode is 0.56 × 10−4 S cm−1, 0.39 × 10−4 S cm−1 and 0.41 × 10−4 S cm−1, respectively. The three composite sulfur cathodes exhibit similar ionic and electronic conductivities. The SEM images and particle-size distributions (derived from the SEM imaging by statistical analysis) (f–k) show that the mean particle sizes of LBPSI-0.17, LBPSI-0.29 and Li5.5PS4.5Cl1.5 are somewhat close at 2.13, 2.34 and 2.18 μm, respectively. Likewise, the three electrolytes all exhibit wide particle-size distribution over 0–10 μm, with a concentration in the range 0.5–5.0 μm.
Extended Data Fig. 5 Further electrochemical data of the cells prepared with electrolyte–carbon composites containing no sulfur in the cathode and the cells with sulfur cathodes.
a,b, The cycling performance with capacity and Coulomb efficiency of the cell prepared with a LBPSI–C composite cathode (wt% LBPSI:wt% C = 8:2) containing no sulfur (0.25 mA cm−2; LBPSI loading of 6.5 mg cm−2) (a) and the corresponding differential capacity plots (dQ/dV) (b). c, The CV curves of the cell for the first five cycles. The cell in a–c is configured as In/InLi|LBPSI|LBPSI–C. The long-term cycling performance, dQ/dV plots and CV curves altogether show the high stability and reversibility of the redox reaction of LBPSI within the potential window of interest. d, The dQ/dV plots of the cell prepared with Li5.5PS4.5Cl1.5作为阴极中的活性材料(wt% Li5.5附言4.5Cl (四)1.5:wt% C = 8:2),配置为 In/InLi|李5.5附言4.5Cl (四)1.5|李5.5附言4.5Cl (四)1.5-C 代表第 1 个、第 2 个和第 50 个周期;第 1 次和第 50 次循环的 dQ/dV 图在峰位置和强度方面表现出显著差异,表明 Li 存在不可逆的分解5.5附言4.5Cl (四)1.5在第一次充电过程之后,这可能会对硫电池中的界面造成一些永久性损坏。e,f,在放电/充电速率为 0.1C (e) 和相应的差振容量 (dQ/dV) (f) (25 °C) 下,含硫阴极电池的第一周期放电-充电电压曲线,这表明电池中存在 LBPSI 氧化还原,其电压略高于 Li 的电压2S/S 的 S/S 和 Li5.5附言4.5Cl (四)1.5氧化还原(如果有的话)发生在与 Li 的电压范围非常重叠的电压范围内2S/S. g,h,在第一次充电(第一次放电过程之后)和在 0.1C 放电后装有 LBPSI 的硫池的原位 EIS 研究:充电/放电代表性状态 (g) 的奈奎斯特图和相应的弛豫时间分布分析 (h)。原位 EIS 研究表明,当充电至 2.8 V 时,在中频处出现一个新的半圆,表明形成了一个新的界面,本文暂时归因于 LBPSI 的表面氧化形成表面层。弛豫时间分析的相应分布,在数学上将频率相关的 EIS 谱转换为基于弛豫的函数 γ(τ) (参考文献。57)显示特征时间常数 (τ) 为 10 时的松弛分布 (γ) 外观−3–100s 并进一步确认新界面的形成。LBPSI 的氧化还原行为的可逆性是通过观察到额外的界面在放电过程中消失来表明的。
扩展数据 图 6 装有 LBPSI 电解质的硫阴极的异位同步加速器硫 K-edge XANES 剖面以及以 LBPSI 作为阴极中活性材料制备的电池的非原位拉曼和 XPS 研究(配置为 In/InLi|LBPSI|LBPSI-C)。
a,在不同放电/充电状态下,以非原位方式对装有 LBPSI 电解质的硫阴极的硫 K-edge XANES 光谱以及硫标准品进行参考。b,原始阴极和阴极的异位拉曼光谱,使用 LBPSI 作为阴极中的活性材料(不含硫),充入电池的 3.2 V。LiI、I 的拉曼光谱2并磨碎了 I2/LiI ((I2+LiI)-BM) 作为参考进行测量。c,d, 原始 LBPSI 材料、原始阴极、电极充电至 3.2 V,随后在电池中放电至 1.4 V 的 I 3d (c) 和 S 2p (d) XPS 数据,该电极在电池中配置为 In/InLi|LBPSI|LBPSI-C(虚线、原始数据;黑线、拟合总数;彩色线、拟合分量)。e,原始电极和电池中充电至 3.2 V 的电极的 I 3d 光谱,以更好地观察信号偏移。我们进行了非原位硫 K-edge XANES 测量,观察到使用 LBPSI 电解质的硫阴极放电并形成 Li2Sx中间体和那个李2S/Li 系列2Sx充电时完全转化为硫。S/KB 和 Li2通过将相应的硫物质与 KB 混合制备的 S/KB 样品用作参考。S/KB 在 2,472.6 eV(白线)和 2,480.0 eV 处显示两个特征;李2S/KB 在 2,473.6、2,476.2 和 2,484.0 eV 处显示三个特征。原始阴极的光谱显示了 S 的特征0在 2,472.6 和 2,480.0 eV 时。当放电至 1.4 V 时,Li 的特性2S 在 2,473.6、2,476.2 和 2,484.0 eV 以及 Li 的 S2Sx在 2,471.8 eV 处出现5,58 元.后续充电后,Li 对应的功能2S 或 Li2Sxdisappear 和 S02,472.6 和 2,480.0 eV 处的特征再次出现。这表明充电已完全转换锂2S(和 Li2Sx) 回到硫磺。当再次放电至 1.4 V 时,S 的特性0消失了,李的特征2S 和 Li2Sx出现。这证明了 SSSRR 在充电和放电过程中的可逆性。在 LBPSI-C 电极 (b) 的拉曼光谱中,与原始电极相比,对于充电至 3.2 V 的电极,在 100-200 cm 处出现宽带−1.峰在 181 厘米左右−1归因于 I2山峰约 110 厘米−1和 167 厘米−1归属于 I3−(参考。59).为了清楚地参考这些峰的分配,我们测量了结晶 LiI、结晶 I 的拉曼光谱2以及 I 的研磨混合物2/LiI(形成 LiI3).我们可以看到,峰在 181 厘米左右−1显然归因于 I 的振动2山峰约 110 厘米−1和 167 厘米−1归因于 I 的振动3−.从 I 3d XPS 光谱 (c,e) 中,我们可以清楚地观察到在将电池充电至 3.2 V (e) 时,I 3d 光谱的信号向更高的结合能转变,证实 SE 表面的 I 具有比 LBPSI 更高的价态 (I−).通过仔细观察拟合的 I 3d 光谱,原始的 LBPSI 电解质和 LBPSI-C 电极显示出阴离子 I−,正如 618.8 eV (3d5/2能源)41 (c). 充电至 3.2 V 时,可清楚地观察到氧化碘物质(暂定为 I2/我3−)42,位于 619.9 eV (3d5/2能源)。此外,在随后放电至 1.4 V 后,氧化碘物质的信号消失,表明碘物质的可逆氧化/还原。对于 S 2p 光谱 (d),原始 LBPSI 电解质和电极含有 [PS4] 单位(和 [BS4],即非桥接硫)和 P-S-P(和 B-S-B,即桥接硫)信号,特征 S 2p 信号位于 161.5 eV 和 162.5 eV(2p3/2能源)43,60 元.充电至 3.2 V 的 LBPSI 电极含有氧化硫 (S0),这可以通过 163.6 eV (2p 左右的特征 S 2p 双峰信号)3/2能源)61.放电至 1.4 V 后,氧化硫 (S0) 消失,出现桥接硫和非桥接硫的信号,这表明硫种类的可逆氧化/还原。
扩展数据 图 7 I 扩散的实验证据2沿 SE 粒子表面发生反应 I2作为 redox mediator 和 Li2S.
a–c,I 扩散的证据2沿 SE 粒子表面。a, 与 I 直接接触的 LBPSI 电解质颗粒2b 5 分钟,将 LBPSI 电解质沉淀置于 I2用于与 I 间接接触的瓶盖23 天。c, Li 垂直截面的 EDX 映射5.5附言4.5Cl (四)1.5与 I 间接接触后的电解液沉淀23 天。d、图片显示 Li 的混合过程2S 和 I2在无水乙醇中。沉淀产物的 e,f、XRD 图 (e) 和拉曼光谱 (f)。g,h, Li 反应的表征2S 和 I2以 100 rpm 的转速温和地进行球磨 2 h,使用产品的 XRD 图谱 (g) 和拉曼光谱 (h)。i,j, Li 反应的表征2S 和 I2通过在研钵中进行简单的手工研磨(5 分钟),使用产品的 XRD 模式 (i) 和拉曼光谱 (j)。j 的插图是 Li 混合的视觉图片2S 和 I2在砂浆中手工研磨之前和之后。I 的扩散和渗透2进入电解质沉淀中,如 A,B。当 LBPSI SE 颗粒与碘(棕色)直接接触时,I2在 5 分钟内在 LBPSI 颗粒表面非常迅速地升华和扩散;电解质表面覆盖着棕色碘 (A)。将 LBPSI 颗粒置于装有 I 的瓶盖上2并且用油脂密封瓶子,以防止碘蒸气通过间隙逸出(即间接接触;b). 3 天没有与我直接接触后2,电解质沉淀的外表面/顶表面变为棕色,表明碘蒸气穿过 SE 沉淀 (b),这进一步证明了 I 的扩散2沿晶界和整个 SE 颗粒。请注意,这些实验是在充满 Ar 的手套箱中进行的,而不是在真空中进行的。此外,我们用无碘 Li 进行了相同的间接接触实验5.5附言4.5Cl (四)1.5电解质。对颗粒的横截面进行扫描电子显微镜成像和 EDX 分析 (c)。我们可以看到,元素 I 与 P、S 和 Cl 一起均匀分布在成像区域(几百微米;c). 模拟李之间的反应2S 和 I2,等量的 Li2S 和 I2首先分别加入无水乙醇中,其溶液分别为无色和紫色(步骤1;d) 以及随后的 Li 的两种解决方案2S 和 I2好坏参半。随着颜色的变化(淡黄色,第 2 步),我们观察到沉淀,证实沉淀由结晶的 LiI 和 S 组成(如 e 中的 XRD 图所示)。拉曼光谱进一步显示了对应于 S (f) 的强信号。因此,李2S 与 I 反应2被确认为 S 和 LiI。为了进一步模拟全固态 Li-S 电池内发生的反应条件,反应在固态下进行。具体来说,等摩尔量的 Li2S 和 I2通过以 100 rpm 的温和球磨混合 2 小时(以防止罐子过热),并且在两种材料的固 - 固混合中形成 LiI 和 S(基于 XRD 模式;如 h 所示,拉曼光谱表现出较强的 S 信号 (154 cm)−1, 219 厘米−1和 473 厘米−1)、我2(信号灯约 181 厘米−1) 和 I3−(110 厘米−1和 167 厘米−1)59.事实上,即使通过在砂浆中简单地手工研磨,这两种材料也会很快反应 (j);在 5 min 的研磨过程中,两种材料反应形成 LiI(基于 XRD 图谱;i)、S 和 I3− (Raman spectrum; j). The feasibility of the chemical reaction between I2 and Li2S that we experimentally confirmed above is strong evidence for us to conclude that the occurrence of redox mediation in the cell at high charging rates are not cascade reactions (that is, occurring sequentially without interplay). Further, the 0.3–0.4 V higher potential for iodine redox over that of sulfur redox (Fig. 3a) serves as the theoretical basis for a chemical reaction between the two couples. This is distinct from the behaviour of sulfur cells using Li5.5PS4.5Cl1.5, in which the SE redox is expected to occur simultaneously with sulfur redox owing to the lack of potential difference (Fig. 3b).
Extended Data Fig. 8 Characterizations and electrochemical performance of ASSLSBs using Li3PS4 and 70Li3PS4·30LiI.
Li5.5PS4.5Cl1.5 was used as the electrolyte separator for the ASSLSBs for its high ionic conductivity. a,b, Powder XRD patterns of the Li3PS4 (a) and 70Li3PS4·30LiI (b). c, Nyquist plots of impedance spectra of Li3PS4 and 70Li3PS4·30LiI for the measurement of the respective ionic conductivity. d, The first-cycle discharge–charge voltage profile of ASSLSBs at 0.05C. e, Charging-rate performance with varied charging rates (labelled) and a constant discharging rate of 1C. Cells were subjected to an activation process by charging at progressively increasing rates of 0.05–0.8C for several cycles before being charged at 2C (sulfur loading: 1.0 mg cm−2). f,g, Discharge–charge voltage profiles of ASSLSBs with charging rates from 2C to 30C using Li3PS4 (f) and 70Li3PS4·30LiI (g) as the catholyte, respectively. h, Nyquist plot for the measurement of the ionic conductivity of LiI (the room-temperature ionic conductivity is measured to be 0.7 × 10−6 S cm−1). On discharge, the iodine species (more precisely, the LiI) can serve as ionically conducting facilitator in the cathode (h) because the as-formed LiI would remain in close contact to the sulfur that it has redox-mediated, and as a moderate ionic conductor (0.7 × 10−6 S cm−1; h) can thus assist in bridging the ionic transport path and enhance the discharge kinetics. We have further demonstrated the much-improved SSSRR kinetics enabled by another iodine-containing sulfide electrolyte (70Li3PS4·30LiI), which highlights the universality of the iodine-based surficial redox-mediating strategy. Li3PS4 and 70Li3PS4·30LiI electrolytes were synthesized to investigate whether the iodine-based redox mediating takes effect in these electrolytes. The two electrolytes are glass ceramics, of which the crystalline phase herein is confirmed to be Li3PS4 (Pnma phase)62 and Li4PS4I (P4/nmm phase)63 by XRD, respectively (a,b). The Li3PS4 and 70Li3PS4·30LiI electrolytes show similar room-temperature ionic conductivity of 0.17 mS cm−1 and 0.13 mS cm−1, respectively (c). We prepared sulfur cathodes using Li3PS4 and 70Li3PS4·30LiI electrolytes in the same way as for those using LBPSI. The Li5.5PS4.5Cl1.5 electrolyte was used as the separator for the cells. The cell with 70Li3PS4·30LiI, when charged at 0.05C, shows a further voltage plateau at 2.7 V, which is consistent with the LBPSI cell and is the result of the redox of iodine (d). The rate performance of the sulfur cathode with 70Li3PS4·30LiI is superior to that using Li3PS4. The cell with 70Li3PS4·30LiI exhibits a high specific capacity of 1,300 mAh g−1 at a charging rate of 2C and maintains 660 mAh g−1 at 10C (discharging rate constant at 1C). At low rates of 0.05C to 0.5C for the first several cycles, the cell fitted with Li3PS4 shows a higher capacity than the cell using 70Li3PS4·30LiI. However, at charging rates of 2C and 10C, it shows lower capacities of 1,113 mAh g−1 and 422 mAh g−1, respectively, than that using 70Li3PS4·阴极中 30LiI。因此,我们认为基于碘的氧化还原介导效应应适用于表面含有碘的各种 SE。
扩展数据 图 9 ASSLSB 的长期循环性能。
a,b,装有 Li 的电池的放电-充电电压曲线5.5附言4.5Cl (四)1.5电解质 (a) 和 LBPSI 电解质 (b) 在不同循环次数上以 0.2C 的放电/充电速率(硫负荷:1.5 mg cm−2).c,装有 LBPSI 电解质的电池在 5,000 次循环中以 2C 的放电/充电速率(硫负载:1.1 mg cm)的放电-充电电压曲线−2).d,在 25,000 次循环中以 5C 的放电/充电速率(硫负载:1.1 mg cm)的电池的放电-充电电压曲线−2).e,装有 Li 的电池的放电-充电电压曲线5.5附言4.5Cl (四)1.5电解液在 10,000 次循环中以 5C 的放电/充电速率(硫负载量:1.1 mg cm−2) 作为比较。f,在 30 °C 下使用 LBPSI 和 Li 的放电-充电循环期间 ASSLSBs 的堆栈压力演变5.5附言4.5Cl (四)1.5电解质。Δp 表示一个完整放电-充电循环内堆栈压力的变化,\(\overline{\Delta p}\) 是五个循环的平均值。两个电池在循环过程中都显示出明显的堆栈压力变化,表明电极的体积膨胀和收缩;然而,使用 LBPSI 的单元在一个周期内压力变化的平均幅度远低于 Li5.5附言4.5Cl (四)1.5 (\({\overline{\Delta p}}_{{\rm{LBPSI}}}=0.45\,{\rm{MPa}}\);\({\overline{\Delta p}}_{{\rm{LiPSCI}}}=1.08\,{\rm{MPa}}\)),这表明在 LBPSI 的情况下,微观体积变化的缓冲作用更深。g,h,装有 LBPSI 的电池以 8C 的放电/充电速率(硫负载量:1.0 mg cm)长期循环−2) (g) 以及 25 °C (h) 时相应的放电-充电电压曲线。通过在 0.05–7C 下循环数个循环,使细胞进行活化过程。该电池具有 744 mAh g 的高容量−1在 8C 下,在 10,000 次循环中具有 78% 的容量保持率。
扩展数据 图 10 ASSLSB 的长期循环性能。
a,在 1,000 次循环中以 1C 的放电/充电速率(硫负载:3.0 mg cm)安装有 LBPSI 的电池的放电-充电电压曲线−2).b,阴极中硫含量高达 45 wt% 的电池的放电-充电电压曲线,以 0.2C 的速率安装 LBPSI(硫负载:1.9 mg cm)−2) 和 25 °C。c,d,装有 LBPSI 的细胞的长期循环,硫负载量为 6.3 mg cm−2 (c) 以及 25 °C 下放电/充电速率为 0.1C (d) 的相应放电-充电电压曲线。e,f,在前两个激活循环中装有 LBPSI 的电池的放电-充电电压曲线 (e) 和在 60 °C 下 10,000 次循环 (f) 中放电/充电速率为 15C 的放电-充电电压曲线(硫负载:1.0 mg cm)−2).g, 装有 Li 的电池的放电-充电电压曲线5.5附言4.5Cl (四)1.5电解液在 10,000 次循环中以 15C 的放电/充电速率(硫负载量:1.0 mg cm−2) 作为比较。h,i, ASSLSBs 在 −20 °C 下的低温性能(硫负载量:1.1 mg cm)−2).h, 使用 LBPSI 和 Li 的电池充电倍率性能5.5附言4.5Cl (四)1.5具有不同充电速率(标记)和 0.2C 恒定放电速率的电解质。第一个循环在 0.05C 的室温下运行以激活。在 0.05–0.20C 的低速率下,Li 电池5.5附言4.5Cl (四)1.5在 -20 °C 时显示出比 LBPSI 的容量略高的容量,这可能是因为 LBPSI 的离子电导率较低。在 0.3C 的充电速率下,两节电池显示出约 820 mAh g 的相当比容量−1.超过该速率,具有 LBPSI 的电池表现出更高的容量,即 652 mAh g 的比容量−1在 0.5C 的充电速率下,保持 466 mAh g−1在 1C 处,而 Li5.5附言4.5Cl (四)1.5比容量为 514 mAh g−1在 0.5C 下,仅保持 295 mAh g−1在 1C. i,在 -20 °C 下以 1C 充电/放电速率进行电池的长期循环。 带有 LBPSI 电解质的电池在 406 mAh g 下显示出稳定的循环−1在 200 次循环中,超过 1,000 次循环几乎没有容量衰减。相比之下,Li5.5附言4.5Cl (四)1.5仅显示 128 mAh g−1在 200 次循环中,保持在 1,000 次循环以上。
补充信息
补充资料
补充图 1-3,补充表 1 和补充参考文献。
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Song, H., Münch, K., Liu, X. 等人。具有快速固-固硫反应的全固态 Li-S 电池。自然 (2025)。https://doi.org/10.1038/s41586-024-08298-9
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数字对象标识符: https://doi.org/10.1038/s41586-024-08298-9