Development of lithium ion battery and recent technology trends

Lithium ion battery has been widely used for cellular phones, notebook pers onal computers and camcorders. Development and technology trend of lithium ion battery are reviewed. The o rigin of lithium ion battery was the research on secondary battery using an electroconductive polymer, polyacetylene, as the negative electrode. Then the focus was shifted from polyacetylene to carbonaceous materials which al so have pi electrons. They were combined with a lithium ion-containing meta l oxide, LiCoO2, as the positive electrode. Capacity of the lithium ion battery has been increased every year and prese nt capacity is twice as much as the initial value. This improvement of capacity has been achieved by improvement of carbonaceo us materials.