Selenium doping induced phase transformation and interlayer expansion boost the zinc storage performance of molybdenum disulfide

Abstract

Aqueous zinc-ion batteries (AZIBs) have attracted extensive attention owing to their environmental friendliness and low cost. However, the application of AZIBs is hindered by the lack of suitable cathode materials due to the sluggish kinetics of divalent Zn²⁺ in host materials. Herein, Se doped MoS₂ nanosheets (MoS_1.8Se_0.2) grown on reduced graphene oxide (rGO) are proposed as a promising cathode for AZIBs. Se doping generates expanded interlayer spacing and a high 1T phase (up to 64%) of MoS₂, which improve its ion diffusion kinetics and electronic conductivity. Remarkably, the MoS_1.8Se_0.2/rGO cathode exhibits a high capacity of 213.6 mA h g⁻¹ at 0.1 A g⁻¹, excellent rate capability of 62.2 mA h g⁻¹ at 8.0 A g⁻¹, and long-term stability with 74.1% capacity retention after 1000 cycles at 1.0 A g⁻¹. Moreover, reversible H⁺/Zn²⁺ co-insertion/extraction behaviors of MoS_1.8Se_0.2/rGO are revealed. This study proves that anion doping of metal sulfides is a feasible method to develop high-performance cathodes for AZIBs.