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

Area of Science:

• Materials Science
• Electrochemistry
• Sustainable Energy

Background:

• Electrocatalytic seawater splitting is crucial for sustainable hydrogen production.
• Developing cost-effective electrocatalysts is key to advancing the hydrogen economy.
• Black carbon waste from metal recovery presents a potential low-cost catalyst source.

Purpose of the Study:

• To investigate the potential of black carbon waste from hydrometallurgical metal recovery as an electrocatalyst for oxygen evolution reaction (OER).
• To analyze the effect of recycling conditions on the material's composition, structure, and OER activity.
• To evaluate the performance of the optimized catalyst in both water and seawater splitting.

Main Methods:

• Characterization of post-leached battery powders using SEM-EDS, XPS, XRD, XRF, and Raman spectroscopy.
• Electrochemical testing to assess OER catalytic activity, including overpotential measurements.
• Comparison of performance against benchmark ruthenium dioxide (RuO2).

Main Results:

• The material leached with sulfuric acid (BAT 1), rich in cobalt compounds (LiCoO2, Co3O4) within a porous carbon matrix, exhibited the best OER performance.
• BAT 1 achieved an overpotential of 226 mV for water splitting and 225 mV for seawater splitting at 10 mA cm⁻².
• Performance was comparable to benchmark RuO2, with only a slight increase in overpotential.

Conclusions:

• Black carbon waste from Li-ion battery recycling can be repurposed as an efficient and stable electrocatalyst for OER.
• The synergistic effect of cobalt-based phases and porous carbon structure enhances catalytic activity.
• This approach offers a sustainable and economical pathway for clean hydrogen production via seawater splitting.