Effect of nano-size LiCoO2 cathode powders on Li-ion cells

• Published in: Journal of power sources Vol. 146; no. 1-2; pp. 27 - 32
• Main Authors: KAWAMURA, Tetsuya, MAKIDERA, Masami, OKADA, Shigeto, KOGA, Kazumichi, MIURA, Norio, YAMAKI, Jun-Ichi
• Format: Conference Proceeding Journal Article
• Language: English
• Published: Lausanne Elsevier Sequoia 26.08.2005
• Subjects: Applied sciences; Direct energy conversion and energy accumulation; Electrical engineering. Electrical power engineering; Electrical power engineering; Electrochemical conversion: primary and secondary batteries, fuel cells; Exact sciences and technology; Lithium battery; Scanning electron microscopy; Nano-sized LiCoO2; Cathode; Lithium Cobalt Oxides; Excess lithium method; Secondary cell; Nanostructure; Electrode material; Li-ion cells; X ray diffractometry; Lithium ion
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2005.03.012

Lithium ion batteries are widely used in many portable devices; however, their power density is not sufficient for use in electric vehicles. One of the most effective methods to improve the power density is the use of very fine cathode particles. We investigated a new excess lithium method of preparing nano-sized LiCoO2 powders. To begin with, lithium acetate and cobalt acetate are mixed by the molar ratio 9, 13 or 21 to 1, uniformly. The mixture is then calcined at 600 deg C for 6 h. Finally, obtained powders are washed with a large amount of water to remove impurity and then dried. Using this method, we obtained nano-sized spherical LiCoO2 particles with a diameter of about 25 nm or needlelike LiCoO2 particles with a diameter of about 5 nm and a length of about 60 nm. The discharge capacity of a Li/5 p.m LiCoO2 cell is 51 mAh g-1, but when the nano-sized LiCoO2 was used, the capacity increased to about 100 mAh g-1 at the same cycling condition.