Nanoelectrical investigation and electrochemical performance of nickel-oxide/carbon sphere hybrids through interface manipulation

Advanced hetero-nanostructured materials for electrochemical devices, such as Li-ion batteries (LiBs), dramatically depend on each functional component and their interfaces to transport and storage charges, where the bottleneck is the sluggish one in series. In this work, we prepare Ni(OH)₂@C hybrids through a continuous feeding in reflux and followed by a hydrothermal treatment. The as-prepared Ni(OH)₂@C can be further converted into NiO@C hybrids after thermal annealing. As a control, Ni(OH)₂&C and NiO&C nanocomposites have also been prepared. Peakforce Tuna measurement shows the conductivity of the NiO@C hybrids is higher than that of NiO&C composites in nanoscale. To further investigate the quality of the interface, 100 charge/discharge cycles of the hybrids are performed in LiBs. The capacity retention of hybrid materials has significantly improved than the simple carbon composites. The enhancement of the electrochemical performance is attributed to the better electric conductivity and smaller charge transfer impedance and strong covalent interface between nickel species and carbon spheres obtained through the controlled seeded deposition.