Electron-Injection Strategy to Boost the Performance of Rich 1t-Mos2/Rgo Cathodes for Zinc-Ion Batteries

Abstract

Due to its excellent electrical conductivity, large interlayer distance, and abundant active sites, 1T-MoS2 is a promising cathode material for aqueous Zn2+ batteries (AZIBs). However, the 1T-MoS2 is metastable and prone to transition to the stable 2H phase, resulting in the confined interlayer distance and the inferior electrical conductivity. In this paper, we implement a 3D/2D assembled 1T-MoS2/rGO composite as a cathode material for AZIBs, in which 1T-MoS2 is anchored on reduced graphene oxide (rGO) by electron-injection engineering. The hydroxyl group of rGO is embedded in the layer structure of MoS2, providing in-situ support, widening the layer spacing, and forming a stable enriched 1T-MoS2. Meanwhile, the rGO flake can effectively alleviate the agglomeration during the growth of MoS2. The well-designed 3D/2D structure can provide more active sites for electrochemical reactions, shorten the diffusion distance of zinc ions, and thus improve the ionic/electronic conductivity of electrode materials. Consequently, the obtained electrode materials reveal excellent rate capacity (304 mAh g-1 at 0.1 A g-1 and 201.1 mAh g-1 at 2 A g-1), as well as long-term cycling stability (with 81% capacity retention after 1000 cycles at 1 A g-1). The electrochemical performance of 1T-MoS2/rGO has been verified through theoretical simulation and other electrochemical measurements. It presents a new approach to developing the application potential of 1T-MoS2/rGO and designing high-performance cathode materials for AZIBs.

Keywords: 1T-MoS2/rGO, electron-injection engineering, sulfur vacancies, Zn-ion batteries, Kinetics