Intercalation-Type V<sub>2</sub>O<sub>3</sub> with Fast Mg<sup>2+</sup> Diffusion Kinetics for High-Capacity and Long-Life Mg-Ion Storage
Cunyuan Pei, Mengda Jin, Yameng Yin, Fangyu Xiong, Yalong Jiang, Xiaofang Yuan, Fang Wang, Qinyou An
Abstract
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 capacity. However, the daunting challenges to its further development are the poor conductivity and large volume change during cycling. In this paper, the unique structure of three-dimensional reduced graphene oxide (rGO) network-supported V2O3 nanoparticles has been prepared and employed as the cathode material for magnesium-ion batteries. With enhanced conductivity and structural stability, V2O3@rGO achieves a high specific capacity (291.3 mAh g–1), enhanced rate performance (185.3 mAh g–1 at a high current density of 2 A g–1), and excellent cycling stability (an 88.5% capacity retention after 1000 cycles at 0.5 A g–1). In addition, the detailed investigations reveal the reversible intercalation Mg-storage mechanism, volume expansion, and the locations of the inserted Mg ions in V2O3. The excellent electrochemical performance and highly reversible intercalation mechanism indicate that the constructed V2O3@rGO is a promising candidate for Mg-ion storage.