Hollow nanostructured NiO particles as an efficient electrode material for lithium-ion energy storage properties

This work has developed a straightforward approach to obtaining NiO hollow structures by using Li₂O₂ as an easily removable template. The easy availability and electrochemically active nature of NiO have attracted researchers' attention as an anode electrode for Li-ion storage applications, including Li-ion secondary batteries (LIBs) and for Li-ion hybrid supercapacitors (LiHSCs; which offer higher power densities than LIBs without compromising energy density). However, NiO usage has been limited to its low reaction reversibility, poor conductivity, and conversion reaction capability. Recently, hollow nanostructured materials have attracted attention as efficient battery materials due to their fascinating structural features. This study presents a modified Li₂O₂-assisted method to obtain porous open 3D architectures of NiO nanostructures. The resultant hollow structures are electrochemically studied as an anode for a LIB, exhibiting excellent stability over hundreds of cycles. The result is recognized as one of the finest among NiO anodes reported. Also, NiO hollow structures studied as anodes for LiHSC devices fabricated with activated carbon cathodes exhibit an outstanding comprehensive electrochemical performance which is better than the typical LIB and supercapacitors.