Lithium Selenide: Unlocking a High-Capacity Cathode for Lithium-Ion Batteries

Lithium selenide has emerged as a promising cathode material owing to its remarkable gravimetric (578 mAh g–1) and volumetric (1659 mAh cm–3) capacities, yet its utilization in practical systems is hindered by low electronic conductivity, serious polyselenide dissolution, and high air sensitivity. These challenges are further exacerbated due to the lack of advanced synthesis methods. Currently, research on lithium selenide cathode material remains in its early stages, with many critical knowledge gaps yet to be filled. This Perspective aims to review the recent progress in this field and provide insights for future research. It covers the physical and chemical properties of lithium selenide, the redox reaction mechanism in different electrolytes, together with the impact of various substrates on the electrochemical behavior. Finally, key future directions are outlined, including innovations in synthesis, enhancement of air stability, improvements to electrolytes, regulation of polyselenide dissolution and shuttle effects, and the feasibility of commercialization.