Rechargeable lithium battery cathodes.: Nonaqueous synthesis, characterization, and electrochemical properties of LiCoO2

A nonaqueous coprecipitation process has been developed to prepare controlled stoichiometry lithium cobalt oxide precipitates. The process involved mixing a methanolic "LiCo(NO3)(3)" solution with a methanolic solution containing tetramethylammonium oxalate as a precipitating agent. The resulting oxalates were readily converted to phase-pure lithium cobalt oxide at 800 degrees C under an oxygen atmosphere. The various starting solutions, oxalate precipitates, and the resulting oxides have been extensively characterized using a variety of techniques, including multinuclear NMR, TGA/DTA, EPR, and XRD analyses. Results indicate that the strong interaction between the metals (Li and Co) that occurred in solution was maintained during precipitation. The calcined precipitate revealed that the desired LiCoO2 phase was formed at 800 degrees C under an O-2 atmosphere. When electrochemically cycled, the material exhibited an initial capacity of similar to 133 (mA h)/g with a fade of 0.02% in capacity per cycle.