Can all-solid-state batteries replace lithium iron phosphate (LiFePO4) batteries?

　　The first to appear as an alternative to lithium iron phosphate batteries was all-solid-state batteries. By using a solid rather than a liquid as the electrolyte between the anode and cathode of the battery, the all-solid battery exhibits sufficient heat resistance and resistance to external shocks. For this reason, some people even think that all-solid-state batteries will change the rules of the game.

　　The energy density of existing lithium-ion batteries is 255Wh/kg. On the other hand, the all-solid-state battery theoretically has a high energy density of up to 495Wh/kg, which has attracted much attention, and many companies including Toyota have been conducting research and development. Some companies have a target of 1000 WH/kg.

　　The Korea Institute of Industrial Technology also announced that it has developed an all-solid-state battery manufacturing technology with an energy density of approximately 445 Wh/L in 2019, which can greatly reduce the size of the battery pack while eliminating the risk of explosion and fire.

　　Samsung SDI researched sulfide-based solid electrolyte materials and began to develop large-scale solid batteries, while LG Chem focused on the research of lithium polymer batteries and curved lithium-ion batteries based on gel polymer materials.

　　In December 2020, the American Quantumscape invested by Volkswagen also announced the results of an all-solid-state battery that can be charged to 80% in 15 minutes.

　　Toyota said that it will showcase a model equipped with an all-solid-state battery at the Tokyo Motor Show in 2020, but it still has many technical problems to be solved, so it has not yet been mass-produced.

　　At the same time, SES (Solid Energy Systems), which is famous in the United States for developing all-solid-state batteries, launched lithium metal batteries through an online event "The 1st SES Battery World" on November 4, 2021. The Apollo 107Ah battery contains a solvent salt electrolyte, which is a mixed lithium metal between existing lithium-ion batteries and all-solid-state batteries. SES explained that this is the world's first release of lithium metal batteries exceeding 100Ah.

　　At present, there is no all-solid-state battery that meets energy density, safety and performance because of high capacity but poor performance. For this reason, the reality is that many companies are developing hybrid forms rather than complete all-solids. General Motors, Hyundai-Kia, Geely, LG, SK and SAIC are investing in SES. Obviously, battery technology is facing a new turning point.

　　Lithium-ion battery (LIB) has become the main energy storage solution in modern social life. Among them, lithium iron phosphate battery is a perfect replacement for lead-acid batteries, and it is the first choice for grid-connected peak shaving, off-grid energy storage, photovoltaic energy storage, UPS, data center and other industries.