# Lithium-ion battery waste as a robust oxygen evolution reaction electrocatalyst for seawater splitting

## TL;DR

This paper shows that waste from lithium-ion batteries can be repurposed as an efficient catalyst for splitting seawater to produce clean hydrogen energy.

## Contribution

The novel contribution is using battery waste as a low-cost, high-performance electrocatalyst for oxygen evolution in seawater splitting.

## Key findings

- Battery waste leached with sulfuric acid showed the best oxygen evolution reaction performance.
- The material achieved overpotentials close to benchmark RuO2 in both water and seawater splitting.
- The catalytic performance is attributed to cobalt-based compounds and a porous carbon structure.

## Abstract

Electrocatalytic seawater splitting seems to be the most promising and urgent demand strategy for clean hydrogen energy production. Utilizing low-cost electrocatalysts is pivotal in the hydrogen economy, as seawater splitting can be made highly efficient and more economical. To meet these expectations, we proposed a novel utilization for the black carbon mass left over from hydrometallurgical metal recovery as an efficient and stable electrocatalyst for oxygen evolution reaction (OER) performed in alkaline media. The SEM-EDS, XPS, XRD, XRF, and Raman analyses revealed that the composition and structure of the post-leached battery powders depend on the hydrometallurgical waste recycling conditions, which in turn affect their OER electrocatalytic activity. In particular, the material leached with sulfuric acid (BAT 1) retained a higher content of cobalt-based compounds (mainly LiCoO2 and Co3O4) embedded within a porous carbon matrix and, resulting in the best catalytic performance among all samples. The enhanced performance of BAT 1 is attributed to the synergy of its cobalt-based phases and the well-developed porous carbon structure, which collectively result in a high electrochemically active surface area. The electrochemical tests proved that Li-ion battery waste has remarkable OER catalytic performance with an overpotential of 226 mV and 225 mV, reaching 10 mA cm− 2 in water splitting and in seawater splitting, respectively, which is only 14 mV and 95 mV higher than for benchmark RuO2 in water splitting and seawater splitting, respectively.

The online version contains supplementary material available at 10.1038/s41598-025-34856-w.