Self-supported Ni decorated NiO nanoflake arrays as promising cathode materials of hybrid batteries

Abstract In this work, self-supported Ni decorated NiO nanoflake arrays are synthesized by using chemical bath deposition and magnetron sputtering methods. The NiO nanoflakes have diameters of 10–15 nm and are cross-linked to form a porous net-like structure with pore diameters ranging from 50 to 350 nm. After Ni sputtering, the NiO nanoflakes are well coated by the Ni particles forming a porous Ni@NiO composite arrays structure. As cathode of hybrid batteries, the Ni@NiO composite arrays exhibit better electrochemical performance with higher capacity (55.6 m Ah g−1 at 1.5 A g−1) than the pure NiO nanoflake sample (29.5 m Ah g−1). Moreover, the Ni@NiO composite electrode is demonstrated with superior cycling stability with 93% capacity retention after 8000 cycles. The introduction of Ni layer is responsible for the improvement of electrochemical properties due to good structural stability and better electrical path.