Designing Anode-Electrolyte Interfaces for Low-Temperature Lithium- and Sodium-Ion Batteries: Challenges and Strategies

Lithium-ion and sodium-ion batteries are gaining prominence as energy storage platforms for extreme environments, particularly at low temperatures. However, the prevailing assumption of electrochemical similarity between Li+ and Na+ in the conventional design paradigm has prevented exploration of their distinct low-temperature degradation pathways, which are intensified by hindered interfacial ion transport at the anode. Herein, we present the differences in solvation structures, desolvation kinetics, and ion-transport mechanisms across the solid-electrolyte interphase (SEI) between Li+ and Na+ at low temperatures. While lithium-ion systems are constrained by sluggish desolvation kinetics, sodium-ion systems face severe interfacial resistance arising from inhomogeneous SEI compositions and weakened interactions between Na+ ions and SEI species. Recognizing these ion-specific interfacial bottlenecks, we propose electrolyte design strategies that enhance ion transport and interfacial stability at the anode. These insights provide rational frameworks for developing next-generation alkali-ion batteries capable of overcoming the distinct challenges posed by low-temperature operation.