Advanced electrolyte design for stable lithium metal anode: From liquid to solid

Li metal anode is among the most promising anode materials for next generation of lithium batteries (Li–O2, Li–S batteries). However, the commercial applications of Li metal batteries have been seriously hindered due to safety and lifetime concerns caused by the formation of Li dendrites. In this review, we focus on the electrolyte designs in handling Li dendritic growth and improving electrochemical performance of Li metal anode, and outline the trend of electrolyte designs from traditional composition adjustment of the liquid electrolyte to molecular design of the solid polymer electrolyte. We aim to provide strategic guidance for the rational design and fabrication of safety electrolytes, and to explore the possibility of these designs in practical application. We critically evaluate the existing challenges and future opportunities associated with this burgeoning field.