One-step synthesis of Broccoli-like Ni3S4 for Mg-ion batteries with excellent long cycle stability

The Broccoli-like Ni3S4 was successfully synthesized by a simple one-step hydrothermal method and used as cathode material for rechargeable magnesium ion batteries. Broccoli-like Ni3S4 consists of a large number of zero-dimensional nanoparticles, so that the ion and electron transport distances are on the nanoscale in either direction, resulting in the same degree of deformation inside and outside the particles during magnesium storage, and the Ni3S4 itself is a dense stacked crystal structure. These properties provide favorable conditions for the structural stability of Ni3S4. In addition, the rich pore structure of Broccoli-like Ni3S4 shortens the ion transport path and provides abundant reaction sites. Due to the excellent characteristics of Broccoli-like Ni3S4, the capacity retention rate is close to 100 % after 200 cycles at the current density of 100 mA g−1.