Lithium battery is a battery that uses lithium metal or lithium alloy as the negative electrode material and non-aqueous electrolyte solution. Due to the very active chemical properties of lithium metal, the processing, storage and use of lithium metal have very high environmental requirements. Therefore, lithium batteries have not been used for a long time. With the development of science and technology, lithium batteries have now become one of the mainstream rechargeable batteries.

• Classification by positive electrode material: Common ones include lithium cobalt oxide (LiCoO₂) batteries, lithium manganese oxide (LiMn₂O₄) batteries, lithium iron phosphate (LiFePO₄) batteries, ternary materials (nickel cobalt manganese oxide NCM or nickel cobalt aluminum oxide NCA) batteries, etc. Lithium batteries with different positive electrode materials have their own advantages and disadvantages in performance, and their application scenarios are also different. For example, lithium cobalt oxide batteries have high energy density and are mostly used in small electronic devices such as mobile phones and laptops; lithium iron phosphate batteries have good safety and long cycle life, and are often used in electric vehicles and energy storage systems.
• Classification by electrolyte form: It can be divided into liquid lithium-ion batteries (LIB) and polymer lithium-ion batteries (PLB). Liquid lithium-ion batteries use liquid electrolytes, have higher energy density and better charge and discharge performance; polymer lithium-ion batteries use solid or gel electrolytes, have higher safety, lighter weight and more flexible shape design, and are often used in some fields that have special requirements for battery shape, such as wearable devices.