Lithium ion batteries have been on the mainstream of electricity storage for a while, providing power for applications ranging from mobile phones to electric/hybrid cars. Still, lithium ion batteries need further development that would further increase their capacity and lifetime.
The Tokyo University of Agriculture and Technology just developed electrode materials for lithium ion batteries. The electrodes of a rechargeable battery are made out of carbon. By using an ultracentrifugal processing technology developed by K&W, a venture firm spun off from the university, the scientists added lithium iron phosphate (LiFePO4) to the anode and tin oxide (SnO2) inside the negative electrode (cathode).
At first, they used SnO2 for the negative electrode – a material which increases its volume due to charging and discharging, also giving the battery short charge/discharge life. In conjunction with that, the scientists used lithium cobalt oxide (LiCoO2) for the anode, a material which showed no degradation of capacity even after 800 charge/discharge cycles. “The ratio of tin oxide and carbon is important,” said Katsuhiko Naoi, professor at the graduate school of the Tokyo University of Agriculture and Technology. “When this ratio was within a certain range, no sign of degradation such as cracking was seen on tin oxide.
The research was funded by Nippon Chemi-Con Corp, which have also developed a Li-ion capacitor made by using the ultracentrifugal technology in which they used carbon nano-fibers and lithium titanate (Li4Ti5O12).