Spent EV Batteries Get Second Life as Higher-Performance Battery Material
story<br>Jacobs School of Engineering<br>Environment
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Spent EV Batteries Get Second Life as Higher-Performance Battery Material
UC San Diego engineers have developed a method to upcycle material from spent lithium iron phosphate (LFP) batteries into a higher-performing component. Their method starts with an end-of-life LFP battery pack (left), from which the cathode is isolated as a powder (center) and transformed into a more energy-dense cathode, called lithium manganese iron phosphate (LMFP). Photos by David Baillot/UC San Diego Jacobs School of Engineering
Story by:
Liezel Labios
llabios@ucsd.edu
Published Date
July 01, 2026
Story by:
Liezel Labios
llabios@ucsd.edu
Topics covered:
Battery Recycling
LFP Batteries
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Key Takeaways
UC San Diego engineers developed an environmentally-friendly method to upcycle material from spent batteries into higher-performing parts.<br>Their method transforms the cathode from LFP batteries — a type of lithium-ion battery used in EVs and energy grids — into one that stores more energy.<br>The upcycling method worked on various types of spent LFP batteries from different manufacturers.
A new approach to battery recycling could turn today’s electric vehicle waste into the building blocks of tomorrow’s higher-performing batteries.
Engineers at the University of California San Diego have developed an environmentally-friendly method to upcycle cathodes from used lithium iron phosphate (LFP) batteries into a more powerful battery material known as lithium manganese iron phosphate (LMFP), which can store more energy than LFP. Instead of breaking down old batteries into raw chemicals and rebuilding them from scratch, the process transforms the existing battery material into a higher-value product.
The findings were published in Joule.
LFP batteries are widely used in electric vehicles and grid-scale energy storage systems because they are safe and long-lasting. They are also less costly than other lithium-ion batteries because they are not made with expensive metals like cobalt or nickel. They now account for nearly half of the global lithium-ion battery market. But as more of these batteries reach the end of their life, efficiently recycling them has become a growing challenge.
Current recycling methods typically use high heat or harsh chemicals to recover battery ingredients. “These processes are not environmentally friendly,” said study first author Wei Li, a postdoctoral researcher in the lab of Zheng Chen, professor in the Aiiso Yufeng Li Family Department of Chemical and Nano Engineering at the UC San Diego Jacobs School of Engineering and senior author of the study. They consume a lot of energy, Li explained, as well as produce large amounts of waste and emissions.
Chen’s lab had previously developed an eco-friendly method to restore spent LFP back into fresh LFP. But that approach just preserved the original chemistry. “After regeneration, it was still LFP,” Li said.
Their new method goes a step further by upgrading it into a higher-performance material: LMFP. “This could offer a more valuable end use for spent batteries,” Chen said.
L-R: Postdoctoral researchers Jiao Lin and Wei Li hold jars containing powders of the upcycled product (LMFP) and spent LFP, respectively.
How spent cathode material is recovered from an end-of-life LFP battery. Left to right: the battery pack's contents are unrolled, cut into smaller sheets, soaked in water, and stirred.
The process begins by opening used battery packs and unrolling their internal structure, known as a “jelly roll” because of its tightly wound layers. Once unrolled and cut into sheets, the material is soaked in water, where gentle mechanical agitation helps separate the cathode coating from the aluminum foil that supports it. “The aluminum foil can also be recycled separately,” Li said.
What remains is a black, sludge-like material containing the spent LFP cathode material. After the water is removed, the material is dried and ground into a black powder.
The researchers then add lithium, manganese and phosphate salts. These provide the ingredients needed to transform LFP into LMFP. But there is one hiccup: the salts have a different crystalline structure from LFP, so they cannot naturally mix together. “Their structures are incompatible,” Li said. “If mixed directly, the atomic distribution of the end product will not be uniform and will have worse electrochemical performance.”
The team’s strategy was to create an intermediate material called lithium manganese phosphate (LMP). Unlike the original salts, LMP has a crystalline structure that closely matches...