Li+ migration and transformation at the interface: A review for stable Li metal anode

Li metal anode has attracted widespread attention in recent years because of its high theoretical capacity and low electrochemical potential. It has been regarded as the most promising anode materials for next-generation battery systems with high energy density. Unfortunately, till now, it can not be used in actual batteries because of the uneven Li+ migration and transformation at the electrode/electrolyte interface, which results in low coulombic efficiency, poor cycling life, and even safety hazards. In this review, we aim at the interficial chemistry of Li metal anode, strategically summarize the formation mechanism of electrode/electrolyte interface and solvated sheath. Meanwhile, we review the current progress for regulating the interficial chemistry, including but not limited electrolyte designs, electrode surface functionalization, composite Li electrode, etc. Finally, the remaining challenges and future opportunities regarding this burgeoning field are also outlined at the end. We hope that such an elaborately organized review will benefit the readers interested to create more possibilities in the future.