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UCSD - University of California - San Diego

07/01/2026 | Press release | Distributed by Public on 07/01/2026 08:04

Spent EV Batteries Get Second Life as Higher-Performance Battery Material

Published Date

July 01, 2026

Article Content

Key Takeaways

  • UC San Diego engineers developed an environmentally-friendly method to upcycle material from spent batteries into higher-performing parts.
  • 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.
  • 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 of 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 LFP. This makes the two materials compatible for mixing.

The spent LFP cathode undergoes upcycling. Left to right: a jar of zirconia balls is being prepared, to which a powder mixture (consisting of spent LFP and salts) will be added; the mixture is placed in a ball miller, where the zirconia balls bump against the powder to ground and mix it into finer particles; the processed powder is isolated; and finally, the LFP and salt powder mixture is placed in a furnace.

To make this transformation happen, the powder mixture - containing spent LFP and the salts - is first mechanically ground and mixed into finer particles. This mixing also distributes the ingredients evenly and brings them into close contact.

The powder is then isolated and heated. "This is where the exciting chemistry happens," Chen said. As the powder is heated, the salts first react to form LMP. Because LMP and LFP share nearly identical crystalline structures, they can combine more uniformly than the original ingredients could. As heating continues, manganese atoms gradually spread throughout the material and replace some of the iron atoms. This rearrangement of atoms transforms the mixture into a single, uniform LMFP structure.

A thin carbon coating also forms around each particle during this stage. This coating improves electrical conductivity and protects the material during repeated charge-discharge cycles.

The result is an upcycled battery material that stores more energy than the original LFP while preserving its durability and safety.

Researchers showed that their upcycling method works on different types of spent LFP batteries from different manufacturers. It can also be scaled to kilogram quantities. Moreover, the upcycled material performs reliably in both laboratory coin cell batteries and larger pouch cells similar to those used in commercial electric vehicles and energy storage systems.

Next steps include further optimizing the process efficiency and yield to improve industrial viability. Researchers will also explore how to better control the morphology and composition during upcycling to further increase the performance of the LMFP product.

Full study: "Generating Isomorphous Intermediates Overcomes Synthesis Barriers for Scalable Direct Upcycling of LiFePO4 Battery Cathodes"

This work was mainly supported by a faculty discretionary fund to Zheng Chen.

Disclosures: Zheng Chen and Wei Li are listed as inventors on a patent application related to the direct upcycling of sLFP to LMFP, filed through the UC San Diego Office of Innovation and Commercialization.

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