Solid electrolyte interface formation and stabilization strategies in emerging non-lithium metal ion storage systems

Abstract Non-lithium metal ion storage systems (NLMISs) and batteries have emerged as promising alternatives for next-generation energy storage, with the solid electrolyte interphase (SEI) playing a pivotal role in determining their electrochemical performance and long-term stability. This review systematically examines the applications and evolving trends of NLMISs, with a focus on sodium (Na), potassium (K), magnesium (Mg), and calcium (Ca)-based systems. The chemical composition, formation mechanisms, and key influencing factors of SEI layers in these systems are comprehensively analyzed. Furthermore, the critical functions of SEI films in enhancing ion transport, suppressing side reactions, and improving cycling stability are discussed. Strategies to optimize SEI stability, including advanced material design, interfacial engineering, and nanostructuring, are critically evaluated. Additionally, the impact of SEI properties on battery performance and summarize state-of-the-art characterization techniques for SEI investigation are summaried. Despite significant progress, challenges such as interfacial degradation and electrolyte compatibility remain unresolved. Finally, future research directions are outlined, highlighting the potential of SEI engineering in sustainable energy storage and the integration of novel materials and technologies for high-performance NLMISs. Highlights This review systematically analyzes the formation mechanisms and chemical composition of solid electrolyte interphase (SEI) layers in emerging non-lithium metal ion (Na, K, Mg, Ca) storage systems, highlighting their critical role in enabling long-term cycling stability and preventing electrolyte degradation. It presents practical stabilization strategies, including advanced electrolytes, nanostructured materials, and artificial interface engineering, that enhance battery performance while addressing key challenges such as interfacial degradation and electrolyte compatibility. Discussion While advanced electrolytes and artificial SEI designs promise superior battery performance, their synthesis often relies on energy-intensive processes or scarce elements; thus, a controversial yet necessary discussion arises as to whether a “green” battery technology can be truly sustainable if its manufacturing footprint outweighs the operational benefits in terms of cycle life and efficiency. Graphical abstract