Regulating lithium deposition via electropolymerization of acrylonitrile in rechargeable lithium metal batteries

We report acrylonitrile (AN) as an effective additive in carbonate-based electrolytes to enable uniform and dense lithium (Li) deposition and to improve the coulombic efficiency of Li metal anode. Our electrochemical, spectroscopic, and theoretical study reveal that AN is cathodically electropolymerized on the Li surface prior to the electrochemical decomposition of the electrolyte during Li deposition. The resultant polyacrylonitrile artificial solid electrolyte interphase enables uniform nucleation and growth of Li deposition with significantly reduced side reactions. The effectiveness of the AN additive is demonstrated in 0.4 Ah Li parallel to LiNi0.6Mn0.2Co0.2O2 pouch cells (using 50-mu m Li anode, 3 mAh cm(-2) cathode areal capacity, and 4 g Ah(-1) electrolyte) with excellent cycle stability under realistic charge-discharge condition.

Automated summary

The addition of acrylonitrile (AN) in carbonate-based electrolytes has been reported as an effective method to achieve uniform and dense lithium (Li) deposition and improve the coulombic efficiency of Li metal anodes. The electrochemical, spectroscopic, and theoretical studies show that AN is cathodically electropolymerized on the Li surface, forming a polyacrylonitrile artificial solid electrolyte interface that allows for uniform nucleation and growth of Li deposition with reduced side reactions. The effectiveness of AN additive is demonstrated in Li pouch cells with excellent cycle stability under realistic charge-discharge conditions.