硫化物固态电解质薄膜的室温干法制备和全固态电池性能

Preparation and all-solid-state battery performance of sulfide solid electrolyte membranes via a solvent-free approach at room temperature

硫化物固态电解质具有高室温离子电导率,但机械强度差难以形成实用电解质层。因此,提出聚合物粘接剂预纤维化的策略,实现了硫化物电解质复合膜的室温干法制备提升了全固态电池的性能。通过PTFE乳液破乳干燥制备了预纤维化的PTFE干粉,采用Li6PS5Cl电解质和纤维化PTFE在室温辊压下成功制备了超薄(~35μm)和高离子电导率(3.17 mS/cm)的硫化物固态电解质复合膜。采用铌酸锂包覆的钴酸锂(LCO@LNO)为正极材料,通过室温干法工艺,制备了正极材料、硫化物电解质、导电剂的复合正极薄膜。通过超薄锂铟合金、电解质复合膜、正极复合膜的简单堆叠,制备了全固态薄膜电池,实现了正极材料134.1 mAh/g的可逆比容量,全电池188Wh/kg的比能量和100次的稳定循环。

Solid-state sulfide electrolytes have high room-temperature ionic conductivities,but their poor mechanical strength makes it difficult to prepare practical electrolyte layers.Herein,the present work proposed a strategy of pre-fiberizing polymer adhesives to achieve the solvent-free preparation of sulfide electrolyte composite membranes at room temperature,thereby enhancing the performance of all-solid-state batteries.Pre-fiberized PTFE fiber powder was prepared by the demulsification of PTFE emulsion followed by drying.An ultrathin sulfide solid electrolyte composite membrane(~35μm)with high ionic conductivity(3.17 mS/cm)was successfully prepared using Li6PS5Cl electrolyte and roller pressing at room temperature.Using lithium cobalt oxide coated with lithium niobate(LCO@LNO)as the cathode material,a composite cathode membrane comprising the positive electrode material,electrolyte,and conductive agent was prepared via the same solvent-free process as electrolyte membranes at room temperature.An all-solid-state thin-film battery was prepared by stacking ultra-thin lithium indium alloy,electrolyte composite membrane,and cathode composite membrane,which achieves a reversible specific capacity of 134.1 mAh/g,an energy density of 188 Wh/kg,and 100 stable cycles.