Structural and electrochemical properties of LiNi0.3Co0.7O2 synthesized bydifferent low-temperature techniques

Single phase LiNi1-yCoyO2 (y = 0.7) with fine particles were prepared by tw o different low-temperature methods, namely sol-gel and combustion techniqu es. It was found that bulk quantities of submicron-sized particles of layer ed LiNi0.3Co0.7O2 can be obtained at temperatures below 400 degrees C by th ese solution techniques. The methods involved the mixing of either acetates or nitrates of the metals, Ni and Co, with a chelating agent, carboxylic a cid (sol-gel method) or a complexing agent, glycine (combustion method) in an aqueous medium. Both carboxylic acid and glycine acted as fuels, decompo sed the homogeneous precipitate of metal complexes at low temperature, and yielded the free impurity LiNi0.3Co0.7O2 compound. The synthesized products were characterized by structural (XRD, SEM), spectroscopic (FTIR) and ther mal (DTA-TG) analyses. The electrochemical performance of the synthesized p roducts in rechargeable Lithium cells were evaluated using a non-aqueous or ganic electrolyte mixture of 1M LiPF6 in EC + DMC. The electrochemical beha vior of synthesized LiNi0.7Co0.3O2 is discussed in relation with its synthe sis procedures. (C) 1999 Elsevier Science Ltd. All rights reserved.