Simple fabrication of porous NiO nanoflowers: Growth mechanism, shape evolution and their application into Li-ion batteries

Tailoring the shape of nanomaterials is a key factor to control their properties. In this presentation, individual porous NiO nanoflowers via α-Ni(OH)2 were fabricated through a simple solvothermal process without any surfactants or growth templates and their application in lithium battery was investigated. In the method, nickel acetate and urea were used as starting materials in ethanol media at 190 °C for 3 h followed by calcination at 400 °C. Electron microscopy studies revealed that initially fine nanoparticles precipitate during solvothermal treatment which then undergo aggregation and self-assembly resulting in nanoflowers. In prolonged time, each nanoflower gives rise to a solid well-faceted microparticle. The electrochemical performance of the NiO nanoflowers was investigated by cyclic voltammetry and conventional galvanostatic charge-discharge tests. The results showed an initial high discharge capacity of ∼1330 mAhg−1 after 10 cycles at 0.1 C rate and a stable capacity of 630 mAhg−1 after 40 cycles in the range of 0.01-3.0 V with the excellent columbic efficiency of ∼94%, suggesting that they have a very promising potential in the future application for lithium ion battery.