Operando EDXRD Study of All‐Solid‐State Lithium Batteries Coupling Thioantimonate Superionic Conductors with Metal Sulfide
Operando EDXRD Study of All‐Solid‐State Lithium Batteries Coupling Thioantimonate Superionic Conductors with Metal Sulfide
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DOI：
10.1002/aenm.202002861
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发表时间：
2020-12
影响因子：
27.8
通讯作者：
Xiao Sun;Alyssa M. Stavola;D. Cao;A. Bruck;Ying Wang;Yunlu Zhang;Pengcheng Luan;J. Gallaway;Hongli Zhu
中科院分区：
文献类型：
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作者：
Xiao Sun;Alyssa M. Stavola;D. Cao;A. Bruck;Ying Wang;Yunlu Zhang;Pengcheng Luan;J. Gallaway;Hongli Zhu
硫化物固体电解质具有显着的离子导电性和较低的机械硬度，但电极的电化学和化学稳定性相对较差。因此，将硫化物电解液与合适的正极配对是研制稳定的全固态锂电池的关键。本文系统地合成并研究了一种不同组成的硫代锑酸盐离子导体Li6+xGexSb1−xS5I，其中Li6.6Ge0.6Sb0.4S5I获得了1.6ms cm−1的优异离子导电性。为了提高电池的能量密度和界面兼容性，在不增加界面工程的情况下，将理论容量高(894mAHg−1)、与硫化物电解液相容性好的金属硫化物FeS2阴极与Li6.6Ge0.6Sb0.4S5I耦合在ASLBS中。用能散X射线衍射仪表征了Li6.6Ge0.6Sb0.4S5I和FeS2在循环过程中的结构稳定性，这种方法可以快速收集结构数据，而不需要重新设计或拆卸密封的电池，也不会有被空气污染的风险。对其电化学稳定性进行了评估，确定了0.7V2.4V(对In-Li)的安全工作电压窗口。由于ASLBS中的固体限制，Fe0聚集和多硫化物穿梭效应得到了很好的解决。ASLB在C/10下的初始容量为715mAhg−1，在室温下稳定在220次循环中，容量保持率为84.5%。
Sulfide solid‐state electrolytes have remarkable ionic conductivity and low mechanical stiffness but suffer from relatively narrow electrochemical and chemical stability with electrodes. Therefore, pairing sulfide electrolytes with the proper cathode is crucial in developing stable all‐solid‐state Li batteries (ASLBs). Herein, one type of thioantimonate ion conductor, Li6+xGexSb1−xS5I, with different compositions is systematically synthesized and studied, among these compositions, an outstanding ionic conductivity of 1.6 mS cm−1 is achieved with Li6.6Ge0.6Sb0.4S5I. To improve the energy density and advance the interface compatibility, a metal sulfide FeS2 cathode with a high theoretical capacity (894 mAh g−1) and excellent compatibility with sulfide electrolytes is coupled with Li6.6Ge0.6Sb0.4S5I in ASLBs without additional interface engineering. The structural stabilities of Li6.6Ge0.6Sb0.4S5I and FeS2 during cycling are characterized by operando energy dispersive X‐ray diffraction, which allows rapid collection of structural data without redesigning or disassembling the sealed cells and risking contamination by air. The electrochemical stability is assessed, and a safe operating voltage window ranging from 0.7≈2.4 V (vs. In–Li) is confirmed. Due to the solid confinement in the ASLBs, the Fe0 aggregation and polysulfides shuttle effects are well addressed. The ASLBs exhibit an outstanding initial capacity of 715 mAh g−1 at C/10 and are stable for 220 cycles with a high capacity retention of 84.5% at room temperature.