Amorphous MoS<sub>3</sub> Anchored within Hollow Carbon\nas a Cathode Material for Magnesium-Ion Batteries

Magnesium-ion batteries are considered the next-generation\npromising\nlarge-scale energy storage devices owing to the low-cost and nondendritic\nfeatures of metallic Mg anode. Nevertheless, such strong electrostatic\ninteraction between bivalent Mg<sup>2+</sup> and crystalline cathode\nmaterials will lead to low capacity and poor diffusion kinetics, which\nseriously hinders the further development of magnesium-ion batteries.\nHerein, amorphization and anion-rich strategies are employed to prepare\nwell-designed cathode materials with MoS<sub>3</sub> anchored on hollow\ncarbon nanospheres (a-MoS<sub>3</sub>/HCS). The amorphous MoS<sub>3</sub> provides unrestricted 3D diffusion access and effectively\nboosts the Mg<sup>2+</sup> diffusion kinetics, while the anion-rich\nfeature of MoS<sub>3</sub> offers rich active sites for Mg<sup>2+</sup> storage and finally contributes to a high discharge capacity driven\nby the anionic redox mechanism. Moreover, the effective modification\nof hollow carbon nanospheres buffers the volumetric changes of MoS<sub>3</sub> and improves the electron transfer efficiency. Owing to the\nabove-mentioned multiple advantages, a-MoS<sub>3</sub>/HCS exhibits\nan ultrahigh discharge capacity (489.2 mAh g<sup>–1</sup> at\n50 mA g<sup>–1</sup>) and high cyclic performance (200.1 mAh\ng<sup>–1</sup> at 2 A g<sup>–1</sup> for 300 cycles),\ndistinctly superior to those of crystalline 1T/2H-MoS<sub>2</sub>/HCS\nand 2H-MoS<sub>2</sub>/HCS and surpassing almost all of the molybdenum\nsulfide-based cathodes. Furthermore, the high-performance a-MoS<sub>3</sub>/HCS-based pouch cell with the ability to drive various mini-type\ndevices confirms the potential application values. The excellent magnesium\nstorage properties of a-MoS<sub>3</sub>/HCS are further verified by\nthe related kinetics analysis, DFT theoretical calculation, and reversible\nelectrochemical reactions. The amorphous and redox-rich tactics of\na-MoS<sub>3</sub>/HCS provide an innovative pathway to explore high-efficiency\ncathode materials for various multivalent-ion batteries.