An Insight into the Electrochemical Activity of Al-doped V₂O₃

We design Al-doped V₂O₃ (Al_xV₂O₃) compounds as cathodes of aluminium battery. A citric acid-assisted simple solid-state synthesis is used to produce Al_xV₂O₃ compounds by heating, at different temperature, a reaction mixture of NH₄VO₃, Al(NO₃)₃9H₂O and citric acid under Ar flow. Al-doping in-between layers and at lattice sites of V2O3 is confirmed by structural, vibrational and chemical analyses. The doped compounds obtained at 600 °C and 800 °C are confirmed as Al_0.56V₂O₃ and Al_0.53V₂O₃ corresponding to theoretical capacities 488 and 490 mAh g⁻¹, respectively, for the extraction of doped Al by considering three electron transfer (Al/Al³⁺). The as-synthesized Al_xV₂O₃ compounds are tested as cathodes in aluminium battery with 1.0 M AlCl₃:[EMIM]Cl electrolyte. The electrodes of Al_0.56V₂O₃ and Al_0.53V₂O₃ exhibited the first charge capacity of 415 and 385 mAh g⁻¹, respectively. The electrochemical extraction of doped Al is confirmed by comparisons with bare V2O3 control cathodes and post-cycling structural studies. The extraction of doped Al from Al_xV₂O₃ indicates its promising use in high capacity cathode for Al-ion battery.