Major element of Li-ion cell positive is LiCoO2，negative is mainly C. When charged,
Positive reaction is: LiCoO2 → Li1-xCoO2 + xLi+ + xe-
Negative reaction is: C + xLi+ + xe- → CLix
Total reaction is: LiCoO2 + C → Li1-xCoO2 + CLix
The reaction is reversible as discharged.