Insights into the Degradation Mechanism of the Magnesium Anode in Magnesium-Chalcogen Batteries: Revealing Principles for Anode Design with a 3D-Structured Magnesium Anode

Magnesium-chalcogen batteries are promising post lithium battery systems for large-scale energy storage applications in terms of energy density, material sustainability, safety, and cost. However, the soluble reaction intermediates, such as polysulfides or polyselenides, formed during the electrochemical processes can severely passivate the Mg metal anode, limiting the cycle life of the batteries. It is necessary to rescrutinize the failure in Mg- chalcogen batteries from an anodic perspective. Herein, the Mg metal anode failure mechanism is thoroughly examined, revealing that it is induced by an inhomogeneous Mg deposition promoted by soluble intermediates from chalcogen cathodes. To further confirm the mechanism and solve this anode failure problem, a multifunctional 3D current collector is used to decrease the local current density and regulate the Mg deposition behavior. The present findings are anticipated to provide guidance for anode design, enhance the life-span of Mg-chalcogen batteries, and facilitate the development of other magnesium metal batteries.

Automated summary

Magnesium-chalcogen batteries are potential alternatives to lithium batteries for large-scale energy storage applications due to their advantages in energy density, material sustainability, safety, and cost. However, the formation of soluble reaction intermediates during the electrochemical processes can cause failure in the magnesium metal anode, limiting the cycle life of the batteries. This study thoroughly examines the failure mechanism, which is induced by inhomogeneous magnesium deposition promoted by soluble intermediates from chalcogen cathodes. A multifunctional 3D current collector is proposed to decrease local current density and regulate magnesium deposition behavior to solve this anode failure problem. These findings are expected to guide anode design, enhance the lifespan of magnesium-chalcogen batteries, and contribute to the development of other magnesium metal batteries.