Selenium Defect Boosted Electrochemical Performance of Binder-Free VSe₂ Nanosheets for Aqueous Zinc-Ion Batteries

Abstract

As a typical transition-metal dichalcogenides, vanadium diselenide (VSe 2 ) is a promising electrode material for aqueous zinc-ion batteries due to its metallic characteristics and excellent electronic conductivity. In this work, we propose a strategy of hydrothermal reduction synthesis of stainless-steel (SS)supported VSe 2 nanosheets with defect (VSe 2−x -SS), thereby further improving the conductivity and activity of VSe 2−x -SS. Density functional theory calculations confirmed that Se defect can adjust the adsorption energy of Zn 2+ ions. This means that the adsorption/desorption process of Zn 2+ ions on VSe 2−x -SS is more reversible than that on pure SS-supported VSe 2 (VSe 2 -SS). As a result, the Zn// VSe 2−x -SS battery showed more excellent electrochemical performance than Zn// VSe 2 -SS. The VSe 2−x -SS electrode shows a good specific capacity of 265.2 mA h g −1 (0.2 A g −1 after 150 cycles), satisfactory rate performance, and impressive cyclic stability. In addition, we also have explored the energy-storage mechanism of Zn 2+ ions in this VSe 2−x -SS electrode material. This study provides an effective strategy for the rational design of electrode materials for electrochemical energy-storage devices.

Activated Proton Storage in Molybdenum Selenide through Electronegativity Regulation

“…It can be seen that the these two peaks of MoSe 2 both shift to lower binding energies after oxygen doping, which can be attributed to weakened MoSe bond owing to the existence of Se defects. [ 45 ] According to previous reports, the Se defects can improve conductivity and accelerate ion diffusion, which will effectively optimize electrochemical performance of MoSe 2 cathode. [ 34,45 ] The Raman results in Figure S10 (Supporting Information) show a redshifted A 1g peak of O‐MoSe 2 compared to pure MoSe 2 , which is arising from the weakened interaction between MoSe 2 layers owing to oxygen doping.…”

“…[ 45 ] According to previous reports, the Se defects can improve conductivity and accelerate ion diffusion, which will effectively optimize electrochemical performance of MoSe 2 cathode. [ 34,45 ] The Raman results in Figure S10 (Supporting Information) show a redshifted A 1g peak of O‐MoSe 2 compared to pure MoSe 2 , which is arising from the weakened interaction between MoSe 2 layers owing to oxygen doping. [ 34,46,47 ] Furthermore, the effect of oxygen doping on specific surface area is characterized by the nitrogen adsorption‐desorption isotherm (Figure S11a, Supporting Information).…”

Hexagonal WO3/3D Porous Graphene as a Novel Zinc Intercalation Anode for Aqueous Zinc-Ion Batteries

“…Up to now, most works have been dedicated to the exploration of cathode materials to improve the ZIBs performance, including manganese-based oxides, ,− vanadium-based oxides, − prussian blue analogues, polyanion compounds, , and organic compound materials . Although breakthroughs on the exploration of cathode materials for ZIBs have been achieved, the problems of Zn metal anodes including Zn dendrites, Zn corrosion/hydrogen evolution, and surface passivation, still seriously hinder the overall performance of ZIBs. ,− …”

Methods for Rational Design of Advanced Zn‐Based Batteries

“…Furthermore, sulfur or selenium vacancies have also been adopted in transition metal dichalcogenides to optimize the electrical conductivity, such as sulfur vacancies-rich MoS 2 nanosheets [55] and stainless-steel (SS)-supported VSe 2 nanosheets with selenium vacancies. [56] Cationic vacancy was also developed to improve the electrochemical performance. For example, Zhou et al used an in situ electrochemical strategy to induce Mn defect in MnO intercalation cathode to improve its electrochemical performance.…”