All-solid-state batteries using flame-retardant inorganic solid electrolytes boast of advantages such as safety and wide usable temperature ranges. Although Li₂S with an antifluorite-type structure has a high theoretical capacity, it is challenging to use in all-solid-state batteries because of the insulating nature. Here, we report an antifluorite-type Li₃CuS₂ as a sulfide positive electrode active material with high electronic conductivity. All-solid-state batteries using Li₃CuS₂ were successfully operated without the addition of conductive additives to the positive electrode. The Li₃CuS₂ exhibited an initial charge–discharge capacity of 380 mAh g^–1 with an average discharge voltage of 2.1 V vs Li⁺/Li.

中文翻译：

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全固态电池正极材料Li ₃ CuS _2的合成及电化学性能

使用阻燃无机固体电解质的全固态电池具有安全性和适用温度范围广等优点。尽管具有抗萤石型结构的Li ₂ S具有较高的理论容量，但是由于绝缘性，在全固态电池中使用具有挑战性。在此，我们报道了具有高电导率的抗萤石型Li ₃ CuS ₂作为硫化物正极活性物质。使用Li ₃ CuS _2的全固态电池可成功运行，而无需在正极中添加导电添加剂。Li ₃ CuS ₂的初始充放电容量为380 mAh g^–1，平均放电电压为2.1 V vs Li ⁺ / Li。