Chinese scientists have developed a new solid-state battery at just 4% of the cost of traditional EV batteries. Most EV batteries are made of lithium-iron phosphate or ternary lithium, both containing liquid electrolytes. Liquids have a lower energy storage density than solids. Despite advancements in liquid battery technology, their bulkiness, weight and potential fire risk prevent their usage in lightweight EVs. But researchers at the University of Science and Technology of China (USTC) in Anhui province have been able to develop all-solid-state batteries – using solid electrolytes for conduction – that also come at a fraction of the cost, holding out great promise for commercial applications of the technology. Solid-state batteries have numerous advantages over the conventional kind, such as doubling the energy density, faster charging, and unlimited charging temperatures. As they are non-flammable, non-corrosive and leakproof, these next-generation batteries also represent a much safer option for the electric vehicle and energy storage industries.
However, large-scale application has been held back by high production costs. Solid electrolytes require expensive metals like lanthanum and cobalt, and the manufacturing process requires a high degree of precision and dedicated production lines. To address this challenge, a USTC team led by Professor Ma Cheng developed a new solid electrolyte, called lithium zirconium oxychloride. Its performance was found to be comparable to that of advanced sulphide and chloride solid electrolytes but at only 4% of the cost, according to research published in the journal Nature Communications last month. A commercially viable solid-state lithium battery electrolyte must show high ionic conductivity, good “deformability” or capacity for shock absorption, and cost under USD50 per kg. None of the existing electrolytes can meet all these criteria. Ceramic electrolytes generally lack deformability, while sulphides and chlorides are expensive, all costing over USD200 per kg.
However, the lithium zirconium oxychloride electrolyte developed by Ma and his team achieved room-temperature ionic conductivity that was more than double the standard required for real-life applications. Meanwhile, its excellent deformability allowed the material to maintain its shape under high pressure, meeting application requirements. “The team provided two synthesis routes, one with a raw material cost of only USD11.6 per kg and the other less than USD7 per kg. In application tests, a battery using lithium zirconium oxychloride took only 12 minutes to charge and maintained stable cycles over 2,000 times at room temperature,” USTC said in a statement. Both the academic community and industrial producers have speeded up their pursuit of this next generation technology. However, China’s EV companies have so far opted for semi-solid batteries, given the high material and manufacturing costs of the all-solid variety. Toyota is also pushing solid-state batteries, which will undoubtedly intensify competition in the EV battery field with China, whose lithium-ion battery exports last year accounted for nearly 70% of global shipments, the South China Morning Post reports.
