Challenges and Progress in Anode‐Electrolyte Interfaces for Rechargeable Divalent Metal Batteries

Divalent metal batteries have attracted considerable attention in scientific exploration for sustainable energy storage solutions owing to the abundant reserves of magnesium (Mg) and calcium (Ca), the competitive low redox potentials of the Mg/Mg2+ (–2.37 V vs SHE) and Ca/Ca2+ (–2.87 V vs SHE) couples, as well as the high theoretical capacities of both metal anodes. However, the development of these batteries faces fundamental challenges stemming from the limited cycling stability and efficiency of Mg/Ca metal anodes. These issues primarily originate from the sluggish electrochemical redox kinetics of the divalent metals, particularly at the anode‐electrolyte interfaces. This comprehensive review provides an up‐to‐date overview of advancements in the field of the anode‐electrolyte interface for divalent metal batteries, covering aspects ranging from its formation, morphology, and composition to their influence on the reversible electrochemical deposition of divalent metals. Recent approaches aimed at enhancing the performance of metallic Mg and Ca anodes across various electrolytes are summarized and discussed, with the goal of providing insights for the development of new strategies in future research. Understanding the interfacial chemistry between metal anodes and electrolytes, and establishing stable interfaces is crucial for developing rechargeable divalent metal batteries. This review addresses the interfacial challenges related to magnesium and calcium metal anodes in different electrolyte systems, and explores promising strategies to optimize these interfaces for achieving reversible metal dissolution/deposition and enhancing electrochemical performance.