Chiral electrolytes for rechargeable metal batteries

Abstract

Charge transfer at the liquid (electrolyte)-solid (metal) interfaces is of fundamental importance to metal electrochemical deposition that further determines the reversibility and kinetics of energy-dense rechargeable metal batteries (RMBs). We demonstrate the fast charge transfer at the electrolyte-metal interfaces for lithium metal by designing and synthesizing electrolytes with chiral solvents: R (or S)-1,2-dimethoxypropane (R-DMP or S-DMP) and R (or S)-4-methyl-1,3-dioxolane (R-MDOL or S-MDOL). The chiral-induced spin selectivity is considered to produce spin-polarized metal surfaces, enabling the improvement in charge transfer rate and efficiency. The deposited Li metal in chiral electrolytes shows smooth and uniform morphologies, as well as high initial (>95%) and average (∼99.2%) Coulombic efficiency for Li metal stripping/plating process, thus prolonging the life-span of batteries using thin lithium anode (50 μm) to 400 cycles till 80% capacity retention. This work provides a distinct approach to regulate metal deposition beyond the limitation of ion de-solvation.