60-Second Preparation of High-Entropy Selenides: Suppressing Polyselenides Shuttling for Long-Cycle-Life Sodium-Ion Batteries

Abstract

Metal selenides with excellent electronic conductivity and high theoretical capacity present great superiority as alternative anodes in sodium ion batteries (SIBs). However, they face huge challenges such as severe sodium polyselenides shuttling and slow sodium ion diffusion kinetics. To address these issues, entropy regulation strategy is employed to optimize the presence of Se vacancies and successfully prepared NiCoFeMnCr/CNTs (HE-MSe/CNTs) rich in Se vacancies. This material enhances the adsorption energy for shuttle compounds like Na₂Se₂ and Na₂Se₄, effectively limiting the dissolution of polyselenides and improving the diffusion kinetics of sodium ions as well as the structural thermodynamics of the Na_xHE-MSe/CNTs adsorption phase. Experimental results indicate that HE-MSe/CNTs achieve a highly reversible sodium storage process involving intercalation and conversion reaction mechanisms. This enables a superior rate capability of 400.4 mAh g ⁻¹ at a high current density of 5 A g⁻¹, and long-term durability with 90% retention after 1000 cycles at 1 A g⁻¹. Therefore, utilizing entropy regulation to customize vacancy formation provides new insights and methods for enhancing the performance of SIB anodes.