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The selection of the most suitable crystal structure for ions storage and the investigation of the corresponding reaction mechanism is still an ongoing challenge for the development of Mg-based batteries. In this article, high flexible graphene network supporting different crystal structures of Nb2O5 (TT-Nb2O5@rGO and T-Nb2O5@rGO) are successfully synthesized by a spray-drying-assisted approach. The three-dimensional graphene framework provides high conductivity and avoids the aggregation of Nb2O5 nanoparticles. When employed as electrode materials for energy storage applications, TT-Nb2O5 delivers a higher discharge capacity of 129.5 mAh g−1, about twice that of T-Nb2O5 for Mg-storage, whereas, T-Nb2O5 delivers a much higher capacity (162 mAh g−1) compared with TT-Nb2O5 (129 mAh g−1) for Li-storage. Detailed investigations reveal the Mg intercalation mechanism and lower Mg2+ migration barriers, faster Mg2+ diffusion kinetics of TT-Nb2O5 as cathode material for Mg-storage, and the faster Li+ diffusion kinetics, shorter diffusion distance of T-Nb2O5 as cathode material for Li-storage. Our work demonstrates that exploring the proper crystal structure of Nb2O5 for different ions storage is necessary.

V2O3 is a promising electrode material because of its large tunnel structure consisted of a 3D V–V network, and it exhibits various alkali-metal-ion storage mechanisms with high theoretical capacit...