Range anxiety is one of the core pain points facing the development of electric vehicles, and all solid state batteries are regarded by the industry as the "seed players" to solve this pain point. According to reports, the first high-capacity all solid state battery production line in China has recently been completed and is currently undergoing small-scale testing and production. It is planned to gradually carry out mass production from 2027 to 2030. What are the differences between solid-state batteries and lithium-ion batteries? Can we really solve the "range anxiety" of electric vehicles? What challenges do we need to overcome to achieve large-scale promotion and application in the future? Around these hot topics, the reporter interviewed experts in the field of batteries. First question: What are the differences between lithium-ion batteries and lithium-ion batteries? The biggest difference between all solid state batteries and traditional lithium-ion batteries is the replacement of the electrolyte and the optimization of the entire positive and negative electrode materials. ”Shen Shulei, Dean of the Carbon Neutrality Technology Innovation Research Institute at Wenzhou University, said. Assistant Professor Xiang Yuxuan from the School of Engineering at Xihu University told reporters that all solid state batteries use non flammable solid electrolytes instead of traditional liquid organic electrolytes. Currently, there are three main technical routes: sulfide electrolytes, oxide electrolytes, and polymer electrolytes. Xiang Yuxuan said that the main structures of traditional lithium-ion batteries include graphite negative electrode, lithium iron phosphate positive electrode (or ternary positive electrode), porous polymer separator between positive and negative electrodes, and liquid organic electrolyte. During the process of battery charging and discharging, lithium ions migrate back and forth between the positive and negative electrodes with the help of liquid organic electrolyte. In contrast, all solid state batteries use solid-state electrolyte membranes instead of porous polymer separators and organic electrolytes. During the process of battery charging and discharging, lithium ions between the positive and negative electrodes can be transported through special ion channels in the solid electrolyte. ”Xiang Yuxuan said that all solid state batteries not only avoid problems such as leakage, corrosion, and combustion of liquid organic electrolytes, but also allow the use of higher capacity positive and negative electrode materials, which theoretically has the potential to significantly improve the safety and energy density of batteries. Question 2: How to improve the endurance of electric vehicles? Range anxiety is a pain point in the new energy vehicle industry, and its fundamental reason is that the energy density of lithium-ion batteries is relatively low, making it difficult to provide sufficient electrical energy due to limited battery pack volume and quality. ”Speak to Yuxuan. Explain to Yuxuan that the energy density of lithium-ion batteries is mainly limited by the low specific capacity of the positive and negative electrode materials. Due to the stability and safety of solid-state electrolytes, all solid state batteries can use positive and negative electrode materials with higher theoretical specific capacity, which will directly lead to a significant increase in battery energy density. Moreover, the safety advantage of all solid state batteries allows them to partially reduce the safety structure of traditional batteries during system integration, resulting in a more compact overall structure. If all solid state batteries are applied to electric vehicles, they can store more electricity with the same battery pack size and quality, greatly improving the range of electric vehicles. In theory, electric vehicles can have a range of over 1000 kilometers. ”Xiang Yuxuan believes that although the large-scale production of all solid state batteries still faces technological and cost challenges, in the long run, all solid state batteries are expected to become one of the key breakthroughs in solving the "range anxiety" of electric vehicles. Question 3: How far is it from large-scale promotion and application? At present, the research and development of all solid state batteries is still in its early stages, and their core material is solid electrolytes, which makes them significantly different from the existing manufacturing processes of lithium-ion batteries. ”Xiang Yuxuan told reporters that in order to achieve large-scale promotion and application of all solid state batteries, multiple key technical challenges still need to be solved. Xu Shulei also believes that if all solid state batteries want to balance high energy density and long-term cycling, and achieve large-scale applications, they will face multiple challenges. Xiang Yuxuan analyzed that the core materials such as high-performance solid-state electrolytes in all solid state batteries have high raw material and process costs. For example, the preparation and use of key materials are sensitive to air and require special equipment and strict environmental control. This requires further breakthroughs in large-scale and low-cost synthesis and preparation technologies, so the mature development of the all solid state battery industry chain still needs time. At the same time, a solid solid interface is formed between the positive and negative active materials and the solid electrolyte in all solid state batteries, and the volume change of the active material during charging and discharging will pose a great challenge to the stability of this "rigid" interface contact. For example, when all solid state batteries use silicon carbon negative electrodes, there will be significant volume expansion, resulting in impedance between interfaces. Under experimental conditions, high pressure is required to achieve normal operation of the battery. This requires researchers to conduct in-depth mechanistic studies on the electrochemical and mechanical properties of solid-state electrolytes, in order to break through the problem of solid solid interface stability as soon as possible. ”Xiang Yuxuan said that to overcome the key technical challenges mentioned above, it is necessary to achieve collaborative innovation breakthroughs in multiple fields such as materials and equipment, ultimately promoting the production and application of all solid state batteries towards scale. (New Society)