A cup of tea can recharge you after a long, tiring day. Tea might also be just what spent batteries need to rejuvenate. In a new study, researchers have used natural compounds that they extract from tea leaves to regenerate lithium-ion battery electrode materials.
The study, published in the journal Advanced Materials, could be a cheaper, more energy-efficient, and environmentally friendly way to recycle batteries compared with traditional recycling methods.
Rechargeable lithium-ion batteries in which the cathode is made of lithium iron phosphate are commonly used in power tools and industrial equipment. They are also increasingly becoming the technology of choice for electric vehicles, because they use materials that are far cheaper and more easily available than other battery chemistries that use cobalt and nickel.
As the use of these batteries grows in EVs and other large-scale applications, the future will bring a stockpile of discarded batteries that the world has to contend with. Recycling the valuable materials in these batteries would reduce the environmental impact of disposing batteries in landfills as well as digging up new battery metals.
But current battery recycling relies on metallurgical techniques. This typically involves chopping up battery materials and heating them to high temperatures, burning energy. The techniques also usually break down the materials into individual elements. So metallurgical methods don’t make economic sense for lithium iron phosphate cathodes, which don’t contain valuable elements.
Researchers in China found a way to directly regenerate the entire lithium iron phosphate cathode. They did that using tea compounds called polyphenols, which are antioxidants famous for their health benefits. Polyphenols are rich in hydroxyl groups. These groups donate electrons to the oxidized, degraded iron and converts it back to its original form. The interplay between the electron donors and the lithium salt also restores the crystal lattice of the lithium compound.
The team also addressed the cathode performance due to the damaged or missing carbon layers that typically coat lithium iron phosphate particles. These conductive carbon layers are critical for electron transport. The researchers added an aluminum source during the polyphenol treatment process. The aluminum phosphate reacts with lithium iron phosphate to form conductive patches wherever the carbon layer is fractured.
In the end, the treatment fully restores the composition and structure of the material, giving a cathode that’s almost as good as new.
Source: Yuanyuan Liu et al, Direct Recycling of Degraded LiFePO4 Cathode Material via Natural Electron Donors Healing and Targeted Surface Reconstruction, Advanced Materials, 2025.
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