# Efficient Non‐Invasive Rejuvenation of Spent Lithium Iron Phosphate Batteries Through Controlled Overdischarge

## TL;DR

A new non-invasive method called controlled overdischarge helps revive old lithium iron phosphate batteries, making them last longer and reducing environmental impact.

## Contribution

The COD protocol introduces a scalable and sustainable way to rejuvenate spent LFP batteries by targeting SEI and reducing defects.

## Key findings

- The COD protocol recovers 9.56% of lost battery capacity and extends lifespan by over 200 cycles.
- The method reduces greenhouse gas emissions to 168 g kg−1 and energy consumption to 3 MJ kg−1 of feedstock.
- COD suppresses copper dissolution and reduces Li/Fe antisite defects in spent LFP batteries.

## Abstract

Recycling lithium iron phosphate (LFP) batteries presents critical economic and environmental challenges because of their low metal value and high energy intensity of conventional metallurgical processes. While direct recycling methods offer a pathway for lithium replenishment, they are often hindered by stringent impurity controls and complex operating conditions that limit scalability. Here, we introduce a controlled overdischarge (COD) protocol as a non‐invasive strategy to rejuvenate spent LFP (S‐LFP) batteries. COD selectively decomposes the solid‐electrolyte interphase, releasing trapped Li+ and reducing Li/Fe antisite defects while simultaneously suppressing copper dissolution. The COD protocol recovers 9.56% of lost capacity and extends lifespan by over 200 cycles. Furthermore, compared to metallurgical recycling, this method markedly lowers greenhouse gas emissions to 168 g kg−1 and energy consumption to 3 MJ kg−1 of feedstock. These findings highlight COD as a sustainable and scalable alternative for S‐LFP battery recycling.

This strategy rejuvenates spent lithium iron phosphate battery by non‐invasively targeting Li+ trapped within the solid‐electrolyte interphase (SEI). This method mitigates copper dissolution and reduces Li/Fe antisite defects, achieving 9.56% capacity recovery and 214 cycles lifespan extension. The process requires only 3 MJ kg−1 of energy and emitting 168 g kg−1 of greenhouse gases per feedstock.