Single Li+-ion conducting solid hybrid electrolytes incorporating fibrous LLZO membrane for lithium metal batteries

Abstract

Solid hybrid electrolytes have been actively investigated to address the safety concerns and the growth of lithium dendrites in lithium metal batteries. However, their practical application remains limited due to lithium dendrite growth, which is caused by the low Li+ transference number (tLi+) and poor mechanical properties of the electrolyte. In this study, a single Li+-ion conducting solid hybrid electrolyte was developed by combining fibrous Li6.4La3.0Zr2.0Al0.2O12 (LLZO) membrane with single-ion conducting polymer electrolyte (SIPE) composed of poly(lithium 4-styrenesulfonyl(trifluoromethanesulfonyl)imide) and poly(vinylene carbonate). This solid hybrid electrolyte, referred to as SIPE-LLZO, showed an ionic conductivity of 0.84 × 10−4 S cm−1 and high Li + ion transference number (0.90) at 25 °C. The symmetric Li/SIPE-LLZO/Li cells demonstrated stable lithium plating and stripping behavior for over 2000 h at 25 °C. Moreover, the Li/LiNi0.95Co0.05Mn0.05O2 cell employing SIPE-LLZO exhibited a high capacity retention of 79.8 % after 300 cycles at 0.5C and 45 °C. These results highlight the promise of single-ion conducting solid hybrid electrolytes for enabling high-energy, dendrite-free lithium metal batteries.