In-situ polymerization induced phase separation to develop high-performance self-healable polymeric electrolytes for lithium metal battery

s The polymer electrolytes have become widely reported solid electrolytes in high-energy lithium metal batteries . However, this kind of electrolytes are limited by their tradeoff between ionic conductivity and mechanical strength . In addition, polymer electrolytes usually suffer from cracks or breakage due to the rigid structure. Therefore, these drawbacks have greatly influenced their practical applications in lithium metal batteries. Herein, we developed a novel self-healable polymer electrolyte (SHPE) by in-situ polymerizing the mixture of butyl acrylate and 2-ureido-4-pyrimidinone (UPy) with plastic crystal succinonitrile (SN) and lithium bis (trifuoromethanesulfonyl) imide (LiTFSI), which were premixed to behave as deep eutectic solvent (DES) to enhance the ionic conductivity . We found that SHPE displayed 0.46 mS/cm at 30 °C and its electrochemical window was determined to be 4.7 V. While the low dose of UPy could provide quadruple hydrogen bond to endow the polymer electrolyte with good self-healing capability and increase the polymer mechanical strength. Therefore, the symmetrical Li/Li cell using this SHPE showed stable properties as long as 1400 h. The Li/LiFePO 4 cell revealed good capacity retention (93.8%, 140.6 mAh/g) after 300 cycles at 0.2C. This work may provide a promising strategy to develop high-performance polymer electrolytes for lithium metal batteries.