Lithium batteries were first used in pacemakers. The advantages of lithium battery, such as extremely low self-discharge rate and gentle discharge voltage, make the pacemaker implanted in human body run for a long time without charging. Lithium batteries generally have a nominal voltage higher than 3.0 volts, which is more suitable for integrated circuit power supply. Manganese dioxide batteries are widely used in calculators, digital cameras and watches.

When the battery is overcharged to a voltage higher than 4.2V, it will start to produce side effects. The greater the overcharge pressure, the higher the risk. When the cell voltage of lithium battery is higher than 4.2V, the number of lithium atoms remaining in the cathode material is less than half, and the battery often collapses at this time, resulting in the loss of permanent capacity of the battery. If charging is continued, the subsequent lithium metal will accumulate on the surface of the negative electrode material, because the storage battery of the negative electrode is already full of lithium atoms.