Multifunctional Electrolyte Additives for Better Metal Batteries

The high energy density of rechargeable metal (Li, Na, and Zn) batteries has garnered a lot of interest. However, the poor cycle stability and low Coulomb efficiency(CE), which are mostly brought on by side reactions and dendrite development on the metal anode, place a cap on commercialization. The rational design of electrolytes via incorporating a small dose of additives is a simple, yet effect strategy to address the above issues. The majority of additives govern uniform metal deposition and significantly improve the cycling performance of metal anodes. However, the battery is a complex system and the electrolyte affects both the anode and cathode. Complex reactions during discharge/charge process put forward higher requirements for the functionality of electrolytes, such as improving the stability of the cathode and flame retardant. Thus, multifunctional additives are necessary and have more advantages in building high-performance metal batteries. The recent developments in multifunctional additives for stable and dendrite-free Li/Na/Zn anodes are the major focus of this review. Breakthrough research on multifunctional additives toward the durable cathode and high-compatible electrolytes is also highlighted. Finally, the critical challenges and new perspectives on the optimization of electrolyte formulation via multifunctional additives are emphasized. This review will provide important insight to develop more effective electrolytes for high-performance rechargeable metal batteries.