β-V2O5 as Magnesium Intercalation Cathode

Magnesium batteries have attracted great attention as an alternative to Li-ion batteries but still suffer from limited choice of positive electrode materials. V2O5 exhibits high theoretical capacities, but previous studies have been mostly limited to α-V2O5. Herein, we report on the β-V2O5 polymorph as a Mg intercalation electrode. The structural changes associated with the Mg2+ (de-) intercalation were analyzed by a combination of several characterization techniques: in situ high resolution X-ray diffraction, scanning transmission electron microscopy, electron energy-loss spectroscopy, and X-ray absorption spectroscopy. The reversible capacity reached 361 mAh g-1, the highest value found at room temperature for V2O5 polymorphs.The authors are grateful to the ALBA synchrotron for beamtime (proposal 2021024935). The Spanish Agencia Estatal de Investigación Severo Ochoa FUNFUTURE (CEX2019-000917-S) Excellence Centre distinction, the European Union’s Horizon 2020 research and innovation programme under grant agreement 824066 (E-MAGIC), and Junta de Andalucía (EMERGIA programme, grant 00153) are gratefully acknowledged. G.C.B.A., P.P., R.F.K., and J.C. were solely supported by the Joint Center for Energy Storage Research (JCESR) and Energy Innovation Hub funded by the U.S. Department of Energy (DOE), Office of Science, Basic Energy Sciences. I.R. acknowledges support from the National Science Foundation via grant DMR-2118020. This research used resources of the National Synchrotron Light Source II, a U.S. Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Brookhaven National Laboratory under Contract DE-SC0012704. The authors acknowledge the free distribution of VESTA softwareWith funding from the Spanish government through the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000917-S).Peer reviewe