Cobalt oxide, composite of cobalt oxide, and method for making the same

A method for making a composite of cobalt oxide comprising steps of:

• providing an aluminum nitrate solution;
• introducing a plurality of lithium cobalt oxide particles into the aluminum nitrate solution;
• mixing the plurality of lithium cobalt oxide particles with the aluminum nitrate solution to form a mixture;
• adding a phosphate solution into the mixture to react with the aluminum nitrate solution and form an aluminum phosphate layer on surfaces of the plurality of lithium cobalt oxide particles;
• heat treating the plurality of lithium cobalt oxide particles with the aluminum phosphate layer formed on the surfaces thereof to form a lithium cobalt oxide composite;
• and
• obtaining cobalt (IV) oxide with all lithium ions being deintercalated from lithium cobalt oxide by electrochemical lithium deintercalation in the lithium cobalt oxide composite at a voltage of Vx, wherein 4.5V<Vx≦5V.

A method for making a composite of cobalt oxide comprising steps of:

• providing an aluminum nitrate solution;
• introducing a plurality of lithium cobalt oxide particles into the aluminum nitrate solution;
• mixing the plurality of lithium cobalt oxide particles with the aluminum nitrate solution to form a mixture;
• adding a phosphate solution into the mixture to react with the aluminum nitrate solution and form an aluminum phosphate layer on surfaces of the plurality of lithium cobalt oxide particles;
• heat treating the plurality of lithium cobalt oxide particles with the aluminum phosphate layer formed on the surfaces thereof to form a lithium cobalt oxide composite;
• and
• obtaining CoO2 by electrochemical lithium deintercalation in the lithium cobalt oxide composite at a voltage of Vx, wherein 4.5V<Vx≦5V.