A lithium-ion battery is a type of battery that uses lithium metal or lithium alloy as the negative electrode material and a non-aqueous electrolyte solution. In 1912, Gilbert Lewis first proposed and studied lithium metal batteries. In the 1970s, M.S. Whittingham proposed and began researching lithium-ion batteries. Due to the highly reactive chemical properties of lithium metal, the processing, storage, and use of lithium metal require very strict environmental controls. Therefore, lithium-ion batteries were not used for a long time. With the development of science and technology, lithium-ion batteries have become mainstream.
Lithium-ion batteries can be divided into two main categories: lithium metal batteries and lithium-ion batteries. Lithium-ion batteries do not contain metallic lithium and are rechargeable. The fifth-generation rechargeable battery, the lithium metal battery, was developed in 1996. Its safety, specific capacity, self-discharge rate, and performance ratio are all superior to lithium-ion batteries. Due to its high technical requirements, currently only a few companies in a few countries produce this type of lithium metal battery.
Lithium-ion batteries have the following advantages:
High energy density: Depending on the electrode material, its mass can reach 150~200Wh/kg (540~720kJ/kg). Its volume can reach 250~530Wh/L (0.9~1.9kJ/cm3). [2]
High open-circuit voltage: varies with electrode material, reaching up to 3.3~4.2V.
High output power: up to 300~1500W/kg (@20 seconds), depending on the electrode material. [1] (Source not specified)
No memory effect: Lithium iron phosphate batteries have no memory effect, and the batteries can be charged and discharged at any time without empty charging, making them convenient to use and maintain.
Low self-discharge: <5%~10%/month. The built-in monitoring circuitry of the smart lithium-ion battery is even more effective than the self-discharge current.
Wide operating temperature range: -20℃ to 60℃ for normal operation.
Fast charge and discharge
Therefore, lithium-ion batteries are widely used in consumer electronics, special products, and other fields. A lithium-ion battery is a rechargeable battery whose working principle is the movement of lithium ions between positive and negative electrodes. Lithium-ion batteries use intercalated lithium compounds as electrode materials. Currently, lithium cobalt oxide (LiCoO2), lithium manganese oxide (LiMn2O4), lithium nickel oxide (LiNiO2), and lithium iron phosphate (LiFePO4) are commonly used negative electrode materials for lithium-ion batteries. At the same time, lithium-ion batteries also have the following disadvantages: (1) Intolerant of over-discharge: Under over-discharge conditions (discharge voltage less than 3.0V), excessively intercalated lithium ions will be fixed in the lattice and cannot be released again, resulting in a shortened lifespan, and deep discharge is more likely to damage the battery. Therefore, using extremely low charge will damage the battery, but as long as the battery is charged at high voltage multiple times, it is possible to reactivate the battery's maximum charging capacity. (2) Intolerable overcharging: During overcharging, a large number of lithium ions are stripped from the electrodes, and the lithium ions are not replenished in time, resulting in long-term collapse of the lattice, thereby irreversibly reducing the storage of electrical energy. Therefore, lithium-ion batteries must be used frequently to prevent them from remaining fully charged and constantly plugged into the charger connector. The flow of stored electrons must be kept normal to maintain the battery's long-term health. (3) Aging is unbearable with heat. Unlike other rechargeable batteries, lithium-ion batteries will inevitably experience a slow, natural decline in capacity with cyclic use, or even without use. This is related to usage (unless it's a vicious cycle of excessive inflation leading to lattice layer loss, a process more appropriately called aging loss) and temperature. A possible mechanism is the gradual increase in internal resistance, so high-current electronic products are more prone to thermal degradation, and external temperature should also be prevented.
