Scalable synthesis of NiMoO₄ microspheres with numerous empty nanovoids as an advanced anode material for Li-ion batteries

Closely in line with advances in next-generation energy storage materials, anode materials for lithium-ion batteries (LIBs) with high capacity and long cycle life have been widely explored. As part of the current effort, nickel molybdate (NiMoO₄) microspheres with empty nanovoids are synthesized via spray drying process and subsequent one-step calcination in air. Dextrin in the atomized droplet is phase segregated during the spray drying process and calcined in air atmosphere, resulting in numerous empty nanovoids well-distributed within a microsphere. The empty nanovoids alleviate volume expansion during cycling, shorten lithium-ion diffusion length, and facilitate contact between electrode and electrolyte materials. Along with the high discharge capacity of NiMoO₄ material, as high as 1240 mA h g⁻¹ for the 2nd cycle at a high current density of 1 A g⁻¹, uniquity of the structure enables longer cycle life and higher quality performances. The discharge capacity corresponding to the 500^th cycle is 1020 mA h g⁻¹ and the capacity retention calculated from the 2nd cycle is 82%. In addition, a discharge capacity of 413 mA g⁻¹ is obtained at an extremely high current density of 10 A g⁻¹.