Due to its advantages of high energy density, long cycle life, low self-discharge rate, and no memory effect, lithium-ion batteries stand out from many energy storage technologies and become the most important part of the electrochemical energy storage field at present. In recent years, the application scenarios of lithium-ion batteries have expanded rapidly, from portable electronic products to electric vehicles, home energy storage, industrial energy storage, etc., lithium-ion batteries have penetrated into all aspects of society, which also puts higher requirements on the safety and energy density of lithium-ion batteries.
Traditional lithium-ion batteries mainly rely on organic liquid electrolyte to conduct lithium ions, and the flammable and volatile characteristics of the electrolyte lead to thermal runaway, fire, explosion and other safety risks in the case of overheating, short circuit, overcharge, and mechanical damage. New energy vehicle safety accidents occur from time to time, and ensuring the safe operation of new energy vehicles is the primary task of the current development of the industry. In recent years, through the innovation of battery system structure, the safety of power battery operation has been improved to a certain extent. Facing the future, the development of battery structure innovation to material system innovation is an inevitable trend of power batteries.
Therefore, the development of high safety and high energy density energy storage technology to make up for the shortage of liquid lithium-ion batteries is an important development direction of lithium-ion batteries in the future.
The use of solid electrolytes to replace liquid electrolytes and the development of all-solid-state lithium batteries can solve the energy density bottleneck and safety risks faced by the current liquid ion batteries, and become the most potential next-generation lithium-ion battery follow-up technology. As shown in Figure 1, the structure and working principle of the all-solid lithium battery is similar to that of the liquid lithium ion battery, but the solid electrolyte has high thermal stability and chemical stability, and will not leak, burn or explode, thereby reducing the risk of thermal runaway and improving the intrinsic safety of the battery. At the same time, the solid electrolyte has a high Young's modulus, which can effectively inhibit the growth of lithium dendrites, and is expected to realize the application of metal lithium anode, which greatly improves the energy density of the battery. In addition, the packaging of all-solid-state batteries is easier. The use of bipolar stacking technology in solid-state batteries can reduce the use of inactive materials such as pole ears and leads, and the battery module does not require a cooling system, which is expected to further improve the volume and mass energy density of the system.