Improving cycling stability of Li metal anode in carbonate electrolyte system by CsNO3 embedded polymeric interlayer

Abstract

Currently, batteries used in electric vehicles are led by Li-ion batteries, but the energy density of Li-ion batteries is reaching a limit in terms of the demand of mileage, which is a priority for consumers. In this regard, a Li metal battery is attracting attention as a next-generation battery by using Li metal as the anode material for higher energy density. Unlike the conventional anode material, the Li metal anode is operated in a way of electrodeposition/dissolution on the surface, and thus shows characteristic dendritic growth of Li. Since dendritic growth arouses various problems to electrochemical performances, research is required to solve the dendritic growth problem to increase stability. In this study, an porous polymeric nanofiber interlayer was developed with including CsNO3 additive which have extremely low solubility in carbonate electrolyte through electrospinning method. In fact, significant improvement in stability of the Li metal anode was confirmed by electrochemical analysis. It was also verified that this improvement came from the synergistic effect of Cs$^+$ cations and NO$_3$$^-$ anions through deposition morphology and SEI components. Finally, the possibility of a high-energy-density Li metal battery based on a carbonate electrolyte was presented via electrospun CsNO$_3$ embedded PAN interlayer which can supply CsNO$_3$ continuously for prolonged cycle.