Enhancement of stability and specific charge capacity of alpha-Ni(OH)2 by Mn(II) isomorphic substitution

Abstract

Mixed hydroxide materials with a large specific charge capacity (417 C g−1) and charge retention capacity (86%) even after 5000 galvanostatic charge–discharge processes at 25 A g−1, promising as electrode materials of energy storage devices such as hybrid batteries, are realized by isomorphic substitution of Ni(II) by Mn(II) ions in the turbostratic alpha-nickel hydroxide lattice, generating for the first time double hydroxide salt types (Ni-95 and Ni-75) instead of layered double hydroxide type materials, significantly enhancing the electrochemical properties and stability of nickel hydroxide nanoparticles (Ni-100). The presence of Mn(II) ions in the alpha-Ni(OH)2 structure is confirmed by flame atomic absorption spectrometry (FAAS), X-ray photoelectron spectroscopy (XPS), and X-ray diffractometry (XRD) of the mixed nickel–manganese hydroxide materials.