Effect of Liquid Metal Coating on Improved Cycle Performance of Anode-Free Lithium Metal Battery

Abstract

Although Li-ion battery is one of the most widely used energy storage devices, there have been extensive efforts to push its limit to meet the ever increasing demands to increase its energy density for applications such as electric vehicles, portable electronics, and grid storages. Here, lithium metal anode plays a key role in the next generation energy storage devices, ultimately enabling the anode-free configuration. However, there are major challenges that need to be overcome. These include low Coulombic efficiency and the formation of dendrites. In this work, we adopted gallium-based liquid metal (LM) as a coating layer on a copper current collector to uniformly deposit lithium to prevent the dendrite formation and improve the cycle efficiency. The LM coating effectively improved the cycle performance in the anode-free configuration combined with Li(Ni,Co,Mn)O2 cathode. The effect of the LM coating was confirmed by in situ transmission electron microscopy and optical microscopy observations. LM reduced the charge/discharge overpotentials with its high affinity with lithium. It also contributed to decompose the dendritic lithium in the discharge process reducing the dead lithium disconnected from the current collector.