Ni nanoparticles embedded into cross-linked NiO nanoflakes as enhanced cathode for alkaline batteries
Highlights: • Ni/NiO arrays prepared by hydrothermal synthesis and electrodeposition methods. • Ni/NiO nanoflake arrays show high capacity for alkaline batteries. • Introducing Ni to the NiO nanoflake is favorable for fast electron transfer. - Abstract: Construction of metal/metal oxide composite arrays is highly important for developing advanced electrochemical energy devices. In this work, we report a facile electrodeposition method to embed Ni network into hydrothermal NiO nanoflake arrays. Ni nanoparticles of 10–25 nm are intimately integrated with NiO nanoflakes of 20–30 nm forming cross-linked Ni/NiO composite arrays. The electrochemical potentials of Ni/NiO composite arrays are explored as cathode of alkaline batteries by means of galvanostatic charge/discharge tests and cyclic voltammograms (CV) in KOH solution. Compared with the unmodified NiO nanoflake arrays, the Ni/NiO composite arrays show much better electrochemical properties with higher capacity (100 mAh g{sup −1} vs. 75 mAh g{sup −1} at 2 A g{sup −1}), enhanced cycling life (capacity retention: 96% vs. 82%) after 3800 cycles and improved high-rate capability. The introduction of Ni nanoparticles not only improves the electrical conductivity, but also acts as anchors to fasten the active nanoflakes to achieve long-term cycles.