Stable Anion-Rectifying Poly(alkoxide magnesium) Electrolytes for Reversible Magnesium Metal Batteries
Xuesong Ge, Fuchen Song, Aobing Du, Gaohao Sun, Shu Zhang, Jingwen Zhao, Qingwei Zhang, Xinhong Zhou, Botao Zhang, Guanglei Cui
Abstract
The rechargeable magnesium battery (RMB) has emerged as a safe, cost-effective, and high-energy alternative to conventional batteries. Yet their practical applications have been plagued predominantly by severe Mg passivation induced by anion-triggered interfacial side reactions with Mg-metal anodes. Herein, an anion-rectifying poly(alkoxide magnesium) electrolyte with a high stability is reported. This polymer electrolyte demonstrates exceptional electrochemical performance for reversible Mg plating/stripping with a Coulombic efficiency up to 99.99%, thus enabling highly reversible cycling of the RMBs with 80% capacity retention after 1000 cycles. Furthermore, this polymer electrolyte retains its activity even after exposure to air with 33% relative humidity for 12 h. As a result, the as-assembled Mg//O 2 full batteries deliver significantly improved performance due to their high air stability. This work provides a universal design principle for stable polymer electrolytes toward highly reversible RMBs, which will significantly boost the development of high-energy RMBs.