Development of a Protective Inorganic Interface for Using Metallic Mg Anodes in Next-Generation Mg-Ion Batteries (MAGNIFICO)

Magnesium-ion batteries (MIBs) represent a promising chemistry to potentially be able to achieve higher energy densities for stationary energy storage applications at a lower cost than lithium-ion batteries. This is possible thanks to the natural abundance, low costs, environmental sustainability, and electrochemical properties of magnesium (Mg). However, the major obstacle in the further development of MIBs is the incompatibility of Mg metal anodes with conventional electrolyte solutions (e.g. Mg(TFSI)2 ). In MAGNIFICO, a safe and sustainable wet-chemical approach is designed to develop a Generation 5 anode material by tailoring a protective intermetallic interphase on the surface of Mg metal powder particles. This coating layer will prevent electrolyte decomposition and Mg passivation while maintaining Mg2+ cation diffusion. In the first step of synthesis, the native oxide layer will be removed from the Mg powder surface using environmentally friendly acid solutions under inert atmosphere. In the second step, Bi and Sn-based precursors will react with the fresh Mg surface depositing a stable intermetallic Mg-X interphase. The as-protected Mg metal anode is expected to achieve a long cell lifetime, thereby exceeding the current state-of-the art for MIBs. This innovative strategy will also allow the Mg-powder-based anode to be processed and fabricated using conventional techniques and battery production infrastructure already developed for LIBs.