Halide-stabilized Libh_4, A Room-temperature Lithium Fast-ion Conductor

摘要

Solid state lithium ion electrolytes with conductivity exceeding 10~(-3) Scm~(-1)' and good chemical stability in contact with both cathode and anode electrodes are actively investigated for their application to solid-state batteries and supercapacitors of high energy density. Liquid-free batteries show various advantages over currently commercialized ones. These include safety issues caused by flammable organic electrolytes and irreversible capacity loss during the discharge cycles originated by the solid electrolyte interface. To date, a wide variety of materials have been found to have high lithium ion conductivity. These include oxides, sulfide based crystals and glasses, multimetal halides, and composite-type electrolytes. Such systems have been demonstrated as electrolytes of all-solid-state batteries. However, the oxide ceramic system frequently involves the problem of seriously high grain boundary resistance. Also, the reactivity of the sulride-based electrolytes with cathode materials leads to difficulty in battery design. Thus, efforts in search of a novel electrolyte system have been continued.