Theoretical study of HfS2 as anode material of zinc ion battery in sports wearable equipment

In this study, the density functional theory (DFT) based on first-principles calculations was used to conduct a comprehensive theoretical calculation of the Zn adsorption HfS2 system (Zn-HfS2) to develop the potential of HfS2 as an anode material for zinc ion batteries (ZIBs). The calculation results show that the adsorption energy decreases gradually (-1.368 eV) with the increase of shear deformation. There is a significant charge transfer from Zn to HfS2 monolayer, and the electrons of Zn atoms flow to S atoms. The intrinsic HfS2 shows a band gap value of 2.055 eV, and Zn-HfS2 shows a metal property with a zero band gap. The adsorption of Zn leads to an increase in energy near the Fermi level, indicating that the adsorption of Zn enhances the electronic conductivity of HfS2. The deformation reduces the barrier of Zn in the diffusion path to 0.16 eV. The maximum specific capacity of HfS2 to Zn is 447.445 mAh/g. The calculation results will help promote the application of zinc ion batteries in wearable devices.