In Situ Gel Electrolyte Network Guaranteeing Ionic Communication between Solid Electrolyte and Cathode

Abstract

Solid electrolytes have been regarded as promising candidates replacing organic liquid electrolyte due to much enhanced safety, which is able to use lithium metal as an anode material for high energy system. Among several solid electroytes, garnet-type solid electrolyte has wide electrochemical window as well as high chemical stability and ionic conductivity at room temperature. However, from an assembled full cell’s point of view, high interfacial resistance between electrode and solid electrolyte is a huge obstacle which should be overcome. Herein, we synthesized high ionic conductivy of Gallium-doped garnet-type solid electrolyte (Li6.25Ga0.25La3Zr2O12) having 1.2 mS cm-1 at room temperature and then applied gel polymer electrolyte into cathode by in situ gelation method for a full cell system. The interfacial resistance was reduced by about 260 times and rate capability from 0.05C to 1C was 80%, which is superior to a hybrid of liquid electrolyte and LGLZO cell system. Initial capacity was retained 89% even after 800 cycles at 0.5C.

Keywords: Gel polymer electrolyte, solid electrolyte, Interface resistance, in situ gelation, Lithium batteries