Synthesis of crystallized LiCo 0.2Ni 0.8O 2 films on nickel substrates by soft solution processing

Abstract

LiCo 0.2Ni 0.8O 2 thin-film cathodes are synthesized by soft solution processing (SSP) on nickel substrates in a homemade solution containing lithium and cobalt ions. Single-phase LiCo 0.2Ni 0.8O 2 films are fabricated at 120 °C with a cyclic voltage from 0 to 1.2 V. Their chemical composition, structure and electrochemical activity are checked by inductively coupled plasma-atomic emission spectrometry (ICP-AES), X-ray diffraction (XRD), infrared spectrometry (IR), scanning electron microscopy (SEM) and cyclic voltammetry (CV) pattern analysis. The prepared LiCo 0.2Ni 0.8O 2 films show R3¯m crystallinity. The films consist of many inhomogeneous spherical grains. The films have pores and fissures which provide electrically conductive pathways and very low resistivities. The thin-film electrodes display reasonable electrochemical activity. The formation of LiCo 0.2Ni 0.8O 2 film under our present conditions is based on an absorption, oxidation and dissolution–precipitation mechanism.