Preparation and electrode properties of novel redoxable nanosheets of Mn–Ni oxide with and without vacancy defects

Abstract

As potential cathode materials for thin-film energy storage devices, Mn–Ni oxide nanosheets with the chemical composition H_0.46Mn_0.81Ni_0.19O₂ (M81N19) were prepared. Upon restacking in HNO₃ aqueous solution and re-exfoliation, the Mn–Ni oxide nanosheets produced the novel H_0.58Mn_0.81Ni_0.13O₂ (M81N13) nanosheets with vacancy defects. The chemical composition of the nanosheets was characterized using X-ray absorption spectroscopy, inductively coupled plasma atomic emission spectroscopy, and thermogravimetry. The sizes of the M81N19 and M81N13 nanosheets were compared, and no structural change was observed after Ni dissolution from the nanosheets. The optical properties, the local structure and the electrochemical properties when used as cathodes in Li-ion batteries of the M81N19 and M81N13 nanosheets, were compared.