Enhanced alkali–metal ion storage performance of bimetallic selenide/N-doped carbon core–shell anodes

Abstract

In this research, we developed a ZnSe@Co_0.85Se heterojunction embedded in N-doped carbon (NC), derived from a zeolitic imidazolate framework (ZIF), for use in lithium-ion batteries (LIBs). The material, ZnSeNC@Co_0.85SeNC, exhibited excellent cycling and rate performance, achieving capacities of 944.1 mAh/g at 1.0 A/g and 277.6 mAh/g at 10 A/g. Full-cell tests demonstrated its effectiveness, with a specific capacity of approximately 80 mAh/g, coulombic efficiency near 99 %, and capacity retention of 64 %, corresponding to power and energy densities of 97.2 W kg⁻¹ and 224 Wh kg⁻¹, respectively. We explored the capacity enhancement mechanisms, identifying factors such as activation of crystalline Se, formation of a Se-rich solid-electrolyte interface, and capacitive contributions from reduced metal particles. Computational studies indicated that these improvements were linked to the heterojunction interface of ZnSe, Co_0.85Se, and NC. Additionally, the material’s potential for potassium-ion battery (PIB) applications was assessed, delivering 274.8 mAh/g at 1.0 A/g. This work not only advances our understanding of transition-metal selenides (TMSe) in battery applications but also proposes design strategies for TMSe-based materials for both LIB and PIB anodes.