Fe doping 1T phase MoS2 with enhanced zinc-ion storage ability and durability for high-performance aqueous zinc-ion batteries

Abstract

As a promising cathode material for aqueous zinc-ion batteries, 1T-MoS₂ has been extensively investigated because of its facile two-dimensional ion-diffusion channels and high electrical conductivity. However, the limited number of available Zn storage sites, i.e., limited capacity, hinders its application because the inserted Zn²⁺, which form strong electrostatic interactions with 1T-MoS₂, preventing subsequent Zn²⁺ insertion. Currently, the approach of enlarging the interlayer distance to reduce electrostatic interactions has been commonly used to enhance the capacity and reduce Zn²⁺ migration barriers. However, an enlarged interlayer spacing can weaken the van der Waals force between 1T-MoS₂ monolayers, easily disrupting the structural stability. Herein, to address this issue, an effective strategy based on Fe doping is proposed for 1T-MoS₂ (Fe-1T-MoS₂). The theoretical calculations reveal that Fe doping can simultaneously moderate the rate of decrease in the adsorption energy after gradually increasing the number of stored atoms, and enhance the electron delocalization on metal-O bonds. Therefore, the experiment results show that Fe doping can simultaneously activate more Zn storage sites, thus enhancing the capacity, and stabilize the structural stability for improved cycling performance. Consequently, Fe-1T-MoS₂ exhibits a larger capacity (189 mAh·g⁻¹ at 0.1 A·g⁻¹) and superior cycling stability (78% capacity retention after 400 cycles at 2 A·g⁻¹) than pure 1T-MoS₂. This work may open up a new avenue for constructing high-performance MoS₂-based cathodes.

Graphical abstract