Mobile phone batteries generally use lithium cobalt oxide batteries. When the battery is discharged, its working principle is similar to that of the primary battery. Through redox reaction, chemical energy is converted into electric energy to drive mobile phones. In the graphite electrode with metallic lithium adsorbed on the negative electrode, zero-valent lithium loses 1 electron and undergoes oxidation reaction to become+1 valence lithium ion, which enters the solution and moves to the positive electrode through the lithium ion exchange membrane. The cobalt peroxide electrode of the positive electrode gains 1 electron lost by the negative electrode, and captures lithium ions from the negative electrode for reduction reaction to become lithium cobaltate.