Co9S8/CNTs microspheres as superior-performance cathodes in aqueous ammonium-ion batteries
(1. College of Materials and Advanced Manufacturing, Hunan University of Technology, Zhuzhou 412007, China;
2. School of Materials and Environmental Engineering, Changsha University, Changsha 410022, China)
2. School of Materials and Environmental Engineering, Changsha University, Changsha 410022, China)
Abstract: Coated Co9S8/carbon nanotube (Co9S8/2CNTs) microspheres were constructed and successfully applied to aqueous ammonium-ion batteries. The introduction of carbon nanotubes in the Co9S8 microspheres increased the electronic conductivity, shortened the diffusion distance for NH4+ ions and improved the buffering ability against volume changes in the cycling processes. As a result, Co9S8/2CNTs microspheres had a reversible capacity of 112 mA·h/g at 0.1 A/g. In addition, the ammonium ion energy storage mechanism accompanied by the formation of reversible phase transition product CoSO4·6H2O and establishment/breaking of intermolecular hydrogen bonds in Co9S8/2CNTs was investigated.
Key words: cobalt sulfide; carbon nanotubes; ammonium-ion batteries; composite microspheres; hydrogen bond