Artificial Layers for Lithium Metal Protection

Rechargeable lithium (Li) metal batteries with conventional intercalation cathodes have been considered as the next-generation power systems for smart electronic devices and mobile transportations because of their high theoretical energy densities. Though great successes have been achieved in recent years, the two major issues related to Li metal anode — high reactivity and dendrite growth — still hinder the practical applications of Li metal batteries. The high reactivity of Li metal with electrolyte causes Li loss through the formation of solid electrolyte interphase (SEI) and electrochemically inactive or “dead” Li during cycling, the depletion of electrolyte, and increase in cell resistance, thus leading to short cycle life of Li metal batteries, especially at high current densities. The Li dendrite growth and the flammability of the liquid electrolytes also cause safety concerns of Li metal batteries. The SEI layer plays a critical role in Li metal batteries, but the in-situ generated SEI is not mechanically strong enough to protect Li metal anode during repeated cycling. Using an ex-situ formed layer as an artificial SEI to protect Li metal anode is an appropriate and convenient way. In this talk, we report the development of various kinds of artificial SEI layers to protect Li metal anode and the investigation of their effects on the performance of Li metal batteries with the combination of experimental and simulation results. More details will be discussed during the presentation.