Chemically Induced Activity Recovery of Isolated Lithium in Anode-free Lithium Metal Batteries.

The anode-free lithium metal battery is considered to be an excellent candidate for the new generation energy storage system because of its higher energy density and safety than the traditional lithium metal battery. However, the continuous generation of SEI or isolated Li hinders its practical application. In general, the isolated Li is considered electrochemically inactive because it loses electrical connection with the current collector. Here we show an abnormal phenomenon that the lost capacity appears to be recovered after cycles when the isolated Li reconnects with a deposited Li metal layer. The isolated Li reconnection is ascribed to the chemical induction of the block copolymer coating. The migration of Li+ is affected by the electron delocalization and the electron cloud density of the polymer, which determine the conversion direction of Li+. Based on the mechanism, we propose a strategy to slow down the capacity decay of the anode-free lithium metal battery.