Programme

P.33 -- Poster, ANSWCCMS-2023

Date: Tuesday, 7 November 2023

Time: 13:00 - 14:30

Unraveling the Role of Hydrogen Insertion in Enhancing Electrochemical Performance of V2O5 Cathode for Mg-ion Batteries: A First-Principles Study

Panupol Untarabut (1), Sirisak Singsen (1), Lappawat Ngamwongwan (1), Ittipon Fongkaew (1), Anchalee Junkaew (2), Suwit Suthirakun (3)

(1)School of Physics, Institute of Science, Suranaree University of Technology, Nakhon Ratchasima, Thailand 30000; (2)National Nanotechnology Center (NANOTEC), National Science and Technology Development Agency (NSTDA), Pathum Thani 12120, Thailand; (3)School of Chemistry, Institute of Science, Suranaree University of Technology, Nakhon Ratchasima, Thailand 30000

Vanadium pentoxide (V2O5) is a promising candidate for magnesium-ion (Mg-ion) batteries due to its high theoretical capacity. However, challenges such as sluggish electron-ion conductivity and capacity fading have hindered its commercialization. In this study, we investigate the beneficial effects of introducing a small amount of water into the electrolyte to enhance charge transport kinetics and increase the capacity of the V2O5 cathode. The role of hydrogen (H) insertion, resulting from water dissociation, in these improvements remains unclear. Through first-principles computations, we explore the impact of H insertion on the electronic conductivity, Mg diffusion kinetics, and structural stability during Mg intercalation. Our findings reveal that high concentrations of inserted H significantly reduce the band gap and enhance the electronic conductivity of V2O5. The inserted H also serves as a charge carrier, contributing to the cathode's increased capacity. Notably, the transport kinetics of H are considerably faster than those of Mg. Consequently, it is anticipated that during discharge, the cathode contains a substantial amount of H before Mg intercalation. The pre-inserted H structure accelerates Mg diffusion by lowering the diffusion barrier from 0.93 to 0.23 eV. Additionally, a fully protonated V2O5 cathode effectively suppresses the irreversible alpha to delta phase transition, a leading cause of capacity fading. This enhanced ion transport kinetics and phase transformation suppression result from the weakened electrostatic interaction between Mg ions and lattice oxygen, facilitated by H insertion. These findings offer valuable insights for the rational design of strategies aimed at improving the electrochemical performance of V2O5 cathodes in Mg-ion batteries, ultimately advancing the development of this promising energy storage technology.

Presenter: Untarabut Panupol