Fabrication of g-C3N4/MoS2@PPy composite based high efficient cathode for aqueous zinc ion battery

Abstract

Zn-ion batteries in water, or ZIBs, are thought to be extremely promising substitutes for lithium-ion batteries. However, their commercial uses are limited by the sluggish diffusion of zinc ions in the positive electrode and their poor reversibility. Here, conductive graphite carbon sheets and conductive polypyrrole that have been effectively compounded with MoS₂ (g-C₃N₄/MoS₂@PPy) are intended to serve as the cathode for aqueous Zinc ion battery (AZIBs). MoS₂ may evenly nucleate and develop on the PPy; this prevents MoS₂ from clumping together and enhancing active materials’ use. The g-C₃N₄/MoS₂ materials exhibit layered nanosheets with flower-like morphology after polypyrrole incorporation the flower changes to hierarchical flower-like morphology. The quantity of oxygenous compounds on g-C₃N₄′s loose surface makes this conceivable. The g-C₃N₄/MoS₂@PPy material has a higher specific surface area of 118.21 m²/g compared to MoS₂ and g-C₃N₄/MoS₂. The g-C₃N₄/MoS₂@PPy exhibits a high specific capacity of 191.7 mAh g⁻¹ at 0.1 A g⁻¹. Moreover, the specific capacity may return to 186.7 mAh g⁻¹, 96.1 % capacity retention, if the current density is restored to 0.1 A g⁻¹. The g-C₃N₄/MoS₂@PPy maintain a higher specific capacity of 60 and 48 mAh g⁻¹, respectively, at 1.0 and 3.0 A g⁻¹ for 1000 cycles. After 1000 cycles, the g-C₃N₄/MoS₂@PPy show 100 % columbic efficiency. g-C₃N₄/MoS₂@PPy electrode’s electrochemical reaction kinetics were examined using cyclic voltammetry (CV) measurements, and galvanostatic intermittent titration (GITT). These methods revealed the electrode’s low Zn²⁺ diffusion energy barrier and desirable pseudocapacitive behaviors. The g-C₃N₄/MoS₂@PPy Zn-intercalation process was elucidated using ex-situ characterizations.