전고체 리튬이차전지의 PEO/LLZO 복합고체전해질 특성

Abstract

The PEO/LLZO solid composite electrolyte with high ionic conductivity and low interfacial resistance was prepared by solution casting method. The electrochemical properties such as lithium ion conductivity, lithium ion transference number, electrochemical stability and compatability with lithium metal anode of PEO/LLZO solid composite electrolyte were investigated. The results showed that the addition of LLZO could effectively improve the ionic conductivity, electrochemical stability window, transference number, and compatibility with lithium metal of composite electrolytes. The LLZO 45% content of the PEO/LLZO solid composite electrolyte showed the lowest activation energy and the electrochemical stability at 4.75V (vs Li/Li+). In addition, when the thickness of the PEO/LLZO solid composite electrolyte was 130 μm or more, The behavior of Li+ plating/stripping on lithium symmetric cell was greatly enhanced. The NCM622/Li solid-state lithium ion battery assembled with the PEO/LLZO solid composite electrolytes had good cycling performance. At current rate of 0.5C, the discharge specific capacity remained about 148mAh/g after 100cycles at 60℃.