Due to the chemical reaction characteristics inside the battery, the loss of the battery will be relatively large when discharging in the state of less than 20% of the remaining electric energy or charging in the state of more than 80% of the capacity. Therefore, keeping the power of lithium-ion batteries between 20%~80% helps to reduce battery losses and maintain the high power capacity of the battery for a long time.

Also, never keep your phone charged for a long time, especially for laptops. Regular charging and discharging can help the battery maintain better working condition. Charging and discharging once a month can effectively extend the battery life.