Deposition of Horizontally Stacked Zn Crystals on Single Layer 1T-VSe₂ for Dendrite-Free Zn Metal Anodes

Abstract

Owing to the moderate redox potential and high safety, Zn metal anodes have been garnering great attention. However, the poor reversibility and limited-service period caused by side reactions and dendrites hinder their applications. Here, a novel anode material consisting of a hexagonal 1T-Vanadium diselenide (1T-VSe₂) film on graphene is developed as a zincophilic template to epitaxially electrodeposit hexagonal closest packed Zn to replace the conventional metal substrates in Zn batteries. The 1T-VSe₂/Zn anode induces a horizontally (002)-oriented plate-like Zn crystal deposition morphology instead of randomly oriented grains that prompts the compact Zn deposition. According to density functional theory calculations, the VSe₂ substrate exhibits a higher Zn adsorption (−0.54 eV) than the graphene (−0.38 eV) or neat Zn (−0.48 eV) counterparts, leading to the enhanced zincophilicity and a lower nucleation overpotential, in agreement with the experimental results. The force field-based molecular dynamics simulations visualize Zn nucleation and morphological evolution at the atomistic level. The rapid adatom diffusion on VSe₂ leads to layer-by-layer Zn electrodeposits with higher fraction of the (002) facets to effectively prohibit dendrite formation. The symmetric cell with 1T-VSe₂/Zn delivers an ultra-stable cyclic life of 2500 h with 50 mV overpotential at 1 mA cm⁻² and 1 mAh cm⁻².