Reactive Polymer as Artificial Solid Electrolyte Interface for Stable Lithium Metal Batteries.

Abstract

Lithium (Li)metal anodes have the highest theoretical capacity and lowest electrochemical potential making them ideal for Li metal batteries (LMBs). However, Li dendrite formation on the anode impedes the proper discharge capacity and practical cycle life of LMBs, particularly in carbonate electrolytes.Herein, we developed a reactive alternative polymer namedP(St-MaI) containing carboxylic acid and cyclic ether moieties which would in-situform artificial polymeric solid electrolyte interface (SEI) with Li. This SEI can accommodate volume changes and maintain good interfacial contact. The presence of carboxylic acid and cyclic ether pendant groups greatly contribute to the induction of uniform Li ion deposition. In addition, the presence of benzyl rings makes the polymer have a certain mechanical strength and plays a key role in inhibiting the growth of Lidendrites. As a result, the symmetric Li||Li cell with P(St-MaI)@Li layer can stably cycle for over 900 h under 1 mA cm-2without polarization voltage increasing, while their Li||LiFePO4full batteries maintain high capacity retention of 96% after 930 cycles at 1C in carbonate electrolytes.The innovative strategy of artificialSEI is broadly applicable in designing new materials to inhibit Li dendrite growth on Li metal anodes.