To complement or outperform lithium-ion batteries with liquid electrolyte as energy storage devices, a high-energy as well as high-power anode material must be used in solid-state batteries. An overlooked class of anode materials is the one of conversion/alloy active materials (e.g., SnO₂, which is already extensively studied in liquid electrolyte-based batteries). Conversion/alloy active materials offer high specific capacities and often also fast lithium-ion diffusion and reaction kinetics, which are required for high C-rates and application in high-energy and high-power devices such as battery electric vehicles. To date, there are only very few reports on conversion/alloy active materials─namely, SnO₂─as anode material in sulfide-based solid-state batteries, with a relatively complex electrode design. Otherwise, conversion-alloy active materials are used as a seed layer or interlayer for a homogeneous Li deposition or to mitigate the formation and growth of the SEI, respectively. Within this work, four different conversion/alloy active materials─SnO₂, Sn_0.9Fe_0.1O₂, ZnO, and Zn_0.9Fe_0.1O─are synthesized and incorporated as negative active materials (“anodes”) in composite electrodes into SSBs with Li₆PS₅Cl as solid electrolyte. The structure and the microstructure of the as-synthesized active materials and composite electrodes are investigated by XRD, SEM, and FIB-SEM. All active materials are evaluated based on their C-rate performance and long-term cyclability by galvanostatic cycling under a constant pressure of 40 MPa. Furthermore, light is shed on the degradation processes that take place at the interface between the active material and solid electrolyte. It is evidenced that the decomposition of Li₆PS₅Cl to LiCl, Li₂S, and Li₃P at the anode is amplified by Fe substitution. Lastly, a 2D sheet electrode is designed and cycled to tackle the interfacial degradation processes. This approach leads to an improved C-rate performance (factor of 3) as well as long-term cyclability (factor of 2.3).

中文翻译：

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不同转化/合金活性材料作为锂基固态电池负极的实现


为了补充或超越采用液体电解质作为储能装置的锂离子电池，固态电池必须使用高能量和高功率的阳极材料。一类被忽视的阳极材料是转化/合金活性材料（例如，SnO ₂ ，它已经在液体电解质电池中得到了广泛研究）。转换/合金活性材料提供高比容量，并且通常还具有快速的锂离子扩散和反应动力学，这是高倍率以及电池电动汽车等高能和高功率设备中应用所必需的。迄今为止，关于转化/合金活性材料（即SnO ₂ ）作为硫化物固态电池负极材料的报道很少，其电极设计相对复杂。另外，转化合金活性材料用作种子层或中间层，以实现均匀的锂沉积或分别减轻SEI的形成和生长。在这项工作中，四种不同的转化/合金活性材料─SnO ₂ 、Sn _0.9 Fe _0.1 O ₂ 、ZnO 和 Zn _0.9 Fe _0.1 O─合成并作为复合电极中的负极活性材料（“阳极”）与 Li ₆ PS ₅ PS ₅ Cl在阳极分解为LiCl、Li ₂ S和Li ₃ P通过 Fe 取代而放大。最后，设计并循环使用二维片状电极来解决界面降解过程。这种方法可以提高 C 倍率性能（3 倍）以及长期循环性能（2.3 倍）。