New molten salt repair process recycles high-performance electric vehicle batteries
Researchers from Huazhong University of Science and Technology have developed a molten salt technique that restores the structure and performance of spent lithium-ion battery cathodes with high nickel content. This approach repairs degraded materials found in waste batteries, allowing them to be reused in new batteries. Unlike standard recycling, which recovers metals but destroys the atomic structure, this method regenerates the original crystal order and capacity.
The team studied LiNi0.8Co0.1Mn0.1O2 (NCM811), a cathode material used for its high energy density in electric vehicles. Over time, the NCM811 loses lithium and accumulates defects that reduce its charging capacity. The new process uses a ternary molten salt mixture of lithium hydroxide, lithium nitrate and lithium salicylate. When this mixture is heated, it becomes a liquid and lithium ions can enter the damaged cathode material, reorganizing the atoms back to their original structure.
Microscopic analyzes showed that the regenerated material achieved a uniform monocrystalline structure. The unwanted rock salt layer on the surface was eliminated. The recycled cathode delivered an initial discharge capacity of 196 mAh/g and retained 76 percent of that capacity after 200 cycles, outperforming many existing recycling methods.
“This process effectively heals the internal and surface damage of the cathode material,” says Fangshu He. “It not only replaces the lost lithium, but also restores the ordered layered structure that is essential for long battery life.”
The molten salt technique works at relatively low temperatures and avoids acids or toxic solvents, making it energy efficient and environmentally friendly. The researchers suggest that this could enable a closed loop of battery recycling, where used batteries are converted directly into high-quality materials for new cells.
The current results are based on laboratory research. The team plans to optimize the method for industrial use and evaluate its full environmental impact. This approach could help reduce both the costs and carbon footprint of battery recycling.
Research report:Regeneration of molten salt of single crystalline LiNi0.8Co0.1Mn0.1O2 from end-of-life cathodes
