Battery cathode, a lithium ion battery using the same and processes for preparation thereof

A process for preparing a cathode comprising a current collector and a cathode material coated on and/or filled in the current collector, said cathode material comprising a cathode active substance, a conductive additive and an adhesive, the process comprises coating a slurry comprising the cathode active substance, the conductive additive and the adhesive on the current collector and/or filling the slurry in the current collector, drying and optionally rolling the resulted current collector, wherein the process further comprises forming a layer of lithium cobaltate on a surface of the cathode active substance, the procedure for forming the layer of lithium cobaltate on the surface of the cathode active substance comprises the following steps:

• (1) contacting and reacting a cobalt salt and a cathode active substance with a precipitant of the cobalt salt by stirring at a reaction temperature of 10-90° C.;
• (2) separating the reaction product obtained in step (1) into solid and liquid, washing and drying the resulted solid to prepare the cathode active substance coated with cobalt compound;
• (3) uniformly mixing the cathode active substance coated with cobalt compound obtained in step (2) with a slurry which comprises non-soluble organic solvent and a lithium carbonate and/or lithium hydroxide in a mole ratio of Co:Li=1:0.8-1.2 to prepare a mixture, and then drying the mixture to remove the solvent comprised therein, wherein lithium comes from lithium carbonate and/or lithium hydroxide, and cobalt comes from the cobalt compound formed in step (2);
• (4) calcining the mixture formed in step (3) at 450-900° C. for 4-20 hours to prepare the cathode active substance coated with lithium cobaltate on the surface thereof, and the content of lithium cobaltate is 0.1-15wt % based on a weight of the cathode active substance.