Enhanced charge storage of nanometric ζ-V<sub>2</sub>O<sub>5</sub> in Mg electrolytes
I. Johnson, Gene M. Nolis, Liang Yin, Hyun Deog Yoo, Prakash Parajuli, Arijita Mukherjee, Justin L. Andrews, Mario Lopez, Robert F. Klie, Sarbajit Banerjee, Brian J. Ingram, Saul H. Lapidus, Jordi Cabana, Jawwad A. Darr
Abstract
V2O5 is of interest as a Mg intercalation electrode material for Mg batteries, both in its thermodynamically stable layered polymorph (α-V2O5) and in its metastable tunnel structure (ζ-V2O5). However, such oxide cathodes typically display poor Mg insertion/removal kinetics, with large voltage hysteresis. Herein, we report the synthesis and evaluation of nanosized (ca. 100 nm) ζ-V2O5 in Mg-ion cells, which displays significantly enhanced electrochemical kinetics compared to microsized ζ-V2O5. This effect results in a significant boost in stable discharge capacity (130 mA h g-1) compared to bulk ζ-V2O5 (70 mA h g-1), with reduced voltage hysteresis (1.0 V compared to 1.4 V). This study reveals significant advancements in the use of ζ-V2O5 for Mg-based energy storage and yields a better understanding of the kinetic limiting factors for reversible magnesiation reactions into such phases.