A sulphide lithium super ion conductor is superior to liquid ion conductors for use in rechargeable batteries

We report that a heat-treated Li2S-P2S5 glass-ceramic conductor has an extremely high ionic conductivity of 1.7 x 10(-2) S cm(-1) and the lowest conduction activation energy of 17 kJ mol(-1) at room temperature among lithium-ion conductors reported to date. The optimum conditions of the heat treatment reduce the grain boundary resistance, and the influence of voids, to increase the Li+ ionic conductivity of the solid electrolyte so that it is greater than the conductivities of liquid electrolytes, when the transport number of lithium ions in the inorganic electrolyte is unity.