There are three main routes for solid-state battery electrolyte materials, which are polymers, oxides and sulfides. Each of the three products has advantages and disadvantages, and different companies choose different paths, but at present, no one can fully achieve the balance of technology and mass production costs.
1: European and American companies mainly use polymer routes
The advantage of the polymer is that its conductivity is similar to that of a liquid electrolyte. However, the shortcomings are also obvious, the mechanical strength is insufficient, and there is still the problem of lithium dendrite piercing. In other words, the internal conduction problem of polymer solid-state batteries still exists, and safety cannot be effectively guaranteed. At present, European and American companies mainly use the polymer route.
2: Japanese and Korean enterprises adopt the sulfide route
The sulfide has high conductivity, close to the liquid electrolyte, and the interface is relatively stable, with both strength and processing properties, and high interface compatibility. However, the air stability of sulfur is poor, and when it is exposed to the air, it is easy to react with water and oxygen in the air to produce hydrogen sulfide toxic gas. Therefore, the synthesis, storage, transportation and post-treatment of sulphide electrolytes need to rely heavily on inert gases or drying chambers. As a result, the preparation process is extremely complicated and the cost is high. In addition, the sulfide electrolyte itself is also expensive. At present, mainly Japanese and South Korean companies adopt the sulfide route.
3: Chinese enterprises are more likely to adopt the oxide route
Its advantages are high density, high mechanical strength, and it is not easy to puncture, so it can effectively improve safety. However, it is also its high density that causes the internal impedance to be too large, resulting in poor conductivity. "Its internal impedance is very large, and even affects the actual performance of internal charging and discharging, which is not as good as liquid products."
In all the current solid electrolyte technology routes, the polymer is not so prominent, short board, while the industry maturity is higher.
Long board, due to the high flexibility of polymer electrolyte material, easy processing, the price is only slightly higher than the liquid; The production is compatible with the existing battery process, the equipment cost is not different, and the mass production cost is low. In terms of performance, the polymer material has good contact with the positive and negative electrode material interface, which is conducive to the extension of battery cycle life.