Recently, the research team led by Professor Jinhui Li from the School of Environment, Tsinghua University has proposed a groundbreaking galvanic leaching strategy to address the high entropy increase and low energy efficiency challenges in recycling spent lithium-ion batteries (LIBs). The findings of this research were published in the journal Nature Communications.
LIBs recycling: High Entropy Dilemma
As a cornerstone of clean energy transition, lithium-ion batteries have consumed 70% of global cobalt resources, while millions of tons of spent batteries pose severe environmental risks annually. Conventional metallurgical recycling relies on mechanical crushing and multi-step chemical leaching, leading to surging entropy: structural disorder from shredding, irreversible energy loss from acid/base consumption, and cross-contamination reducing product purity.
Galvanic Effect: The Key to Self-Dismantling Batteries
To tackle these challenges, the team proposed an innovative hydrometallurgical recycling strategy based on the "minimum entropy increase principle," offering a novel approach for the efficient and sustainable recycling of spent lithium-ion batteries. In this strategy, the research team discovered that a micro-galvanic cell system can be formed between the sLIB cathode material (such as LiNi?.?Co?.?Mn?.?O?) and the aluminum foil current collector inside the battery. Through this design, the aluminum foil acts as a zero-valent metal reductant, capable of directionally transferring electrons solely for the reductive decomposition of the waste cathode material, without generating hazardous hydrogen gas or releasing organofluorine pollutants. This method enables the spent lithium-ion battery to "self-disassemble," significantly reducing the entropy increase during the recycling process without destroying the battery's original structure.
Experimental results show that, compared to traditional methods, this technology achieves a lithium recovery rate exceeding 99% and a transition metal recovery rate over 90%, while increasing the electron reduction efficiency by approximately 25 times and the dissolution rate by about 30 times. Thermodynamic calculations indicate that the high potential difference of up to 3.84V (equivalent to about three dry cells) in this galvanic cell system is the key reason why electrons released from the dissolution of the aluminum foil are forced to migrate directionally, solely for the reduction of high-valent metals (Ni??/Co??/Mn??), without causing hydrogen evolution side reactions. The electron migration and charge accumulation effects generated by the galvanic cell system induce preferential dissolution inside the waste lithium-ion battery particles, gradually forming a cavity morphology. Notably, the fluorine-containing organic binders and conductive agents in the spent lithium-ion battery serve as electron transfer pathways and are not dissolved by electron or hydrogen ion attacks, ultimately forming an organic framework, which is fixed in the leaching residue. This, to a certain extent, reduces the difficulty of treating secondary wastewater.
Fig. 1: The design principle and recovery effect of self-assembly galvanic leaching system from spent lithium-ion batteries.
Prospects and Significance
1. The proposed short-path electrochemical leaching strategy eliminates the need for pre-crushing and additional reductants, reducing energy consumption by 11.36%-21.10% and carbon emissions by 5.08%-23.18%, offering a more environmentally friendly solution for lithium-ion battery recycling.
2. This method achieves an economic benefit of $26.52 per kilogram of battery cells, a 21.37%-49.24% improvement over traditional methods, while increasing the metal dissolution rate by over 30 times, laying the foundation for industrial-scale battery recycling applications.
3. By managing process entropy and achieving recovery rates of 99.01% for Li, 91.62% for Ni, 95.15% for Co, and 94.19% for Mn, this technology opens new pathways for low-entropy, high-efficiency recycling of high-value urban minerals like circuit boards and monitors, promoting clean production and a circular economy.
Jinhui Li was the corresponding author of the paper, postdoctoral fellow Jiadong Yu of the School of Environment was the first author of the paper, and Yanjun Liu, the 2023 undergraduate graduate of the School of Environment, was the co-author of the paper. All authors are affiliated with Tsinghua University. The research was supported by the National Natural Science Foundation of China and others.
Link to the paper: https://doi.org/10.1038/s41467-025-57857-9
