Nickel oxide nanocrystals as a lithium-ion battery anode: structure-performance relationship

Highly crystalline NiO nanocrystals were fabricated via annealing electrospun NiO nanofibers. The fabricated NiO nanocrystals were used as anode material in lithium-ion battery. Electrochemical performance of the NiO nanocrystals was compared with the NiO nanofibers. Differences in the electrochemical performance of NiO nanocrystals and NiO nanofibers were co-related with their morphology, crystallinity, and surface chemistry. NiO nanocrystals-based anodes displayed a specific capacity of about 500 mAh/g under current densities of 100, 200, and 500 mA/g i.e., the specific capacity was found to be independent from current density. In contrast, the specific capacity in the case of nanofibers was found to vary between 500 and 900 mAh/g depending upon the current density. Better consistency was also observed for nanocrystals in terms of long cycle life performance. The improved rate capability and consistency in case of NiO nanocrystals was attributed to the formation of stable nickel phase during the repeated cycling.