As the world embraces electric vehicles and portable electronics, the mountain of spent Li ion batteries is growing fast. By 2030, an estimated two million tons of these batteries will reach the end of life each year. Now, a research team led by Prof. Yu Ding at Nanjing University and collaborators has developed a liquid metal method that separates battery electrode materials at room temperature in just 30 minutes, with no heating, no acid leaching, and clean hydrogen as a byproduct. The study is published in National Science Review .
Recycling spent Li ion batteries efficiently is essential, but the process has a stubborn bottleneck: separating the valuable cathode materials from the aluminum foil current collector that holds them in place. Current approaches tackle this problem with brute force. Pyrometallurgy uses high-temperature smelting at over 1000 degrees Celsius, consuming massive amounts of energy. Hydrometallurgy relies on strong acids or alkalis, generating hazardous wastewater. Both methods risk damaging the very materials they aim to recover.
The team, together with collaborators at the University of Shanghai for Science and Technology, Tongji University, and Shanghai Jiao Tong University, has found a gentler solution: liquid metals. Their study (DOI: 10.1093/nsr/nwag142) presents a heating and leaching free strategy for electrode separation. Mingjin Cui, Zhicheng Tian (Nanjing University), Yongqing Gong (Tongji University), and Bo Xu (University of Shanghai for Science and Technology) are co-first authors, with Prof. Yu Ding, Prof. Ping He, and Prof. Menghao Yang as corresponding authors.
The approach uses liquid metals that remain liquid at room temperature. When this alloy contacts aluminum foil, it rapidly wets the surface, breaks through the protective oxide layer, and infiltrates along aluminum grain boundaries, the weak interfaces between microscopic crystal grains. This process dissolves the aluminum from within, causing the foil to disintegrate while leaving the cathode coating intact and undamaged.
The separation takes about 30 minutes at room temperature and requires neither heating nor chemical leaching. “What surprised us most is the universality of this method. It works equally well across all four major cathode chemistries used in commercial batteries,” said Prof. Ding.
Testing confirmed separation efficiencies of approximately 99.4 percent for nickel cobalt manganese oxide (NCM), lithium cobalt oxide (LCO), lithium iron phosphate (LFP), and lithium manganese oxide (LMO). Crucially, the dissolution of valuable transition metals — nickel, cobalt, manganese, and iron, into the liquid metal was negligible, preserving the chemical integrity of the cathode materials.
After separation, the liquid metal can be regenerated simply by adding water. The dissolved aluminum reacts with water to form aluminum oxide, while the refreshed liquid metals are ready for reuse. This regeneration step also produces clean hydrogen gas as a valuable byproduct, with no harmful emissions. Separation efficiency remained above 99.3 percent after multiple regeneration cycles.
“The beauty of this system is that it is truly closed loop. The liquid metal is recycled, the cathode materials are recovered for regeneration, and even the byproduct, hydrogen, has significant economic value as a clean energy carrier,” said Prof. Ding.
The regenerated cathode materials showed excellent electrochemical performance after a straightforward relithiation treatment. Regenerated NCM delivered a reversible capacity of 172 milliampere hours per gram at low current rates, with 96.5 percent capacity retention over 100 charge discharge cycles. LCO, LFP, and LMO cathodes achieved 148, 144, and 138 milliampere hours per gram, respectively.
A techno-economic analysis demonstrated compelling advantages over established industrial methods. The liquid metal method consumes only 3.33 megajoules of energy per kilogram of battery cells processed, less than two-thirds of pyrometallurgy (5.27 MJ/kg) and roughly one seventh of hydrometallurgy (22.18 MJ/kg). Greenhouse gas emissions, water consumption, and total processing costs were also substantially lower. Revenue from recovered materials reached 8.70 dollars per kilogram, the highest among all methods compared.
Gallium (component of liquid metals) is roughly as abundant in the Earth's crust as copper and zinc, so there is strong potential for large-scale supply at lower costs in the future. The researchers note that this method transforms a difficult recycling bottleneck into a simple, room-temperature process.
The researchers believe their liquid metal strategy could offer a scalable, energy efficient, and environmentally friendly pathway for recycling the growing volume of spent batteries worldwide, supporting the transition toward a circular economy for critical battery materials.
M. Cui, Z. Tian, Y. Gong, B. Xu, et al., Heating and leaching-free separation of electrodes by liquid metals for regeneration of spent Li ion batteries, Natl Sci Rev (2026). DOI: 10.1093/nsr/nwag142
National Science Review
Experimental study