NiMn2O4 Nanosheet/Carbon Nanotube Composites for Aqueous Zinc-Ion Batteries

Due to the continuous depletion of lithium resources and the security risks of organic electrolytes such as combustion and explosion, there is an imminent requirement to develop a type of energy accumulation system to adapt to the progression and progress of society. Zinc-ion batteries using aqueous electrolyte have the advantages of high safety, low cost, and environmental friendliness, which make them an ideal alternative to lithium-ion batteries as a next-generation energy storage system. Among the zinc-ion battery cathode materials, manganese-based materials and carbon materials occupy the main positions, respectively. Among them, nickel manganate (NiMn2O4) nanosheets and carbon nanotubes (CNTs) as active materials have received extensive attention. The CNTs could provide electronic conductive channels and NiMn2O4 nanosheets supply more active points for electrochemical reactions. The carbon shell with a porous structure also improves the electron transport and ionic conduction processes, so that the nickel manganate/carbon nanotube (NiMn2O4/CNTs) nanocomposites obtained a high specific capacitance of 333.6 mAh g–1 at a current density of 0.2 A g–1. After 500 cycles at a current density of 0.5 A g–1 led to a high specific capacity of 73.6 mAh g–1, it was shown that the material exhibits excellent comprehensive electrochemical properties. This synergistic strategy of combining structural design and electrochemical activation in NiMn2O4/CNTs nanocomposites can be a reference for other manganese-based cathode materials.