Unveiling Mo doping effects in hydrated vanadium oxide cathodes for high-energy zinc-ion batteries: Evidence from operando synchrotron X-ray and DFT analysis
Journal
Chemical Engineering Journal
Journal Volume
530
Start Page
173302
ISSN
13858947
Date Issued
2026-02-15
Author(s)
Gull, Sanna
Cheng, Hsu-Chen
Li, En-Hao
Chen, Tsung-Yi
Ni, Chung-Sheng
Yu, Wan-Ju
Chang, Hao-Hsiang
Wang, Ai-Yin
Doong, Ruey-An
Chuang, Yu-Chun
Chen, Bo-Hao
Chang, Chung-Kai
Chen, Hsin-Yi Tiffany
Chen, Han-Yi
Abstract
Aqueous zinc-ion batteries (AZIBs) offer strong potential for grid-scale energy storage, yet their performance is often constrained by sluggish Zn2+ diffusion and insufficiently stable cathode hosts. In this work, we develop a Mo-doped hydrated vanadium oxide (MoVOH/VOH) cathode designed to overcome these limitations. Using operando X-ray diffraction, operando XANES, and extended X-ray absorption fine structure (EXAFS) analysis combined with density functional theory (DFT) calculations, we not only elucidate the Zn2+ storage mechanism but also resolve the previously controversial structural position of Mo within the VOH framework. Our results demonstrate that high-oxidation-state Mo ions are predominantly incorporated substitutionally within the V-O layers, rather than occupying interlayer sites. This substitution significantly improves electronic conductivity, accelerates Zn2+ transport, and stabilizes the VOH lattice during repeated cycling. Consequently, the MoVOH/VOH cathode delivers a high capacity of 405 mAh g−1 at 0.1 A g−1, excellent rate capability, and 82% capacity retention after 300 cycles at 5 A g−1, and an energy density of ∼284 Wh kg−1 at 71 W kg−1. These findings demonstrate that Mo doping is an effective strategy for tailoring vanadium-based hosts for high-performance AZIBs and provide direct experimental and theoretical insight into the local structural role of Mo, addressing a key unresolved issue in hydrated vanadium oxides.
Subjects
Aqueous
Cathode material
DFT
Operando XANES
Operando XRD
Publisher
Elsevier B.V.
Type
journal article