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

YY Li and HL Wong and J Wang and WL Peng and YD Shen and MY Xu and Q An and JK Kim and B Yuan and WA Goddard and ZT Luo, ADVANCED ENERGY MATERIALS, 12 (2022).

DOI: 10.1002/aenm.202202983

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).

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