Microwave-assisted synthesis of LiNiO2—a preliminary investigation

Abstract

This paper presents the results of fundamental studies concerning the possibility of synthesizing LiNiO2 by means of a microwave oven. Several attempts involving various precursors have been made with a view to identify suitable combinations of precursors that are microwave receptive and reactive in nature. Also, the optimization of reaction conditions, both in terms of microwave exposure time and period of post-heat-treatment required to synthesize phase-pure LiNiO2, has been made. The optimum synthesis involves two steps, viz. exposure of precursor to microwaves for 5 min followed by a post-treatment of heating the samples in flowing oxygen or in air for about 5 h. Despite the involvement of two steps, this procedure reduces both processing time and cost. Among the various combinations of precursors chosen for the present study a microwave irradiated (5 min) LiOH–Ni(OH)2 combination when subjected to post-heat-treatment in O2 (5 h) results in the formation of a phase-pure LiNiO2 sample, which exhibits good electrochemical performance (163 mAh g−1) as a potential cathode material for lithium cells.