Abstract:

Solid-state batteries possess higher energy density and better safety than commercial lithium-ion batteries.However，solid electrolytes are still suffered from lithium dendrite growth.The current large-scale industrialized polyvinyl oxide（PEO）-based electrolyte was used as the research object.By combining PEO with garnet type electrolyte with high Young′s modulus，the effective inhibition of Li dendrite growth in PEO based composite electrolyte was realized.The ionic conductivity of the electrolyte membrane was increased from 9.8×10^-6 S/cm to 3.8×10^-4 S/cm，and the critical current density of the Li/Li symmetric battery was increased from 0.4 mA/cm² to 1.6 mA/cm².Meanwhile，the assembled pouch cell based on Li metal anode and conventional graphite anode could obtain the energy density of 334.5 W·h/kg and 218.2 W·h/kg，respectively.Additionally，the capacity retention rate of Li cobalate/composite electrolyte/graphite pouch cell was 92.3% after 1 000 cycles，which met the demand of new energy vehicle.

Key words: solid state battery, composited electrolyte, lithium dendrite, new energy vehicles