(Invited) Transforming Metal-Containing Secondary Resources into Functional Materials for Electrochemical Energy Applications
Authors: Dominguez-Benetton Xochitl 
Published: February 2024

Transforming metal-containing waste into functional materials for electrochemical energy applications presents an innovative and sustainable solution to address the growing issue of waste management and resource conservation. By utilizing end-of-life products, off-specification materials, waste materials, and spent materials as secondary resources, this approach can effectively reduce environmental impacts and promote the development of clean energy technologies.
Gas-diffusion electrocrystallization (GDEx) is a novel electrochemical technology that can be used as a step to selectively recover and convert valuable metals from metal-containing waste streams into functional materials for electrochemical energy applications. By leveraging the electrochemical reduction of gases, such as O2 or CO2, for the in-situ production of oxidizing (H2O2) or reducing agents (H2 and CO)—which may also result in the formation of other chemical species, e.g., alkali (OH–) in aqueous media, GDEx facilitates the precipitation of soluble metal precursors. This process results in the formation of metal nanoparticles with controlled compositions, crystal structures, sizes, morphologies, and compositions, tailored for specific electrochemical applications.
In this talk, the principles of the GDEx process will be explained and examples will be provided of its applicability in the direct transformation of metals contained in secondary resources for the production of functional materials for electrochemical applications. Specifically, the production of electrocatalysts for methanol oxidation from the recycling of automotive catalysts leachates will be conveyed, as well as the production of active battery materials for Li-ion batteries, and the recovery of lithium from geothermal brines.
Gas Diffusion Electrocrystallization (GDEx) is a novel and sustainable approach to transform waste materials into functional materials for electrochemical energy applications. This innovative method enables the recovery and synthesis of valuable metal nanoparticles (NPs) from waste streams, such as end-of-life products and industrial leachates, for use in electrocatalysis, energy storage, and fuel cells.
GDEx will be conveyed as a sustainable and scalable technology for the recovery of critical metals, contributing to a circular economy and reducing the environmental impact of mining and refining activities. The opportunity for producing materials with enhanced performance will be portrayed, together with the portent of a customizable and flexible solution which can be integrated with existing recycling chains.
Acknowledgement
This research has received funding from the European Union’s Horizon 2020 and Horizon Europe research and innovation programmes under grant agreements 958302 (PEACOC Project), 101069685 (Rhinoceros Project), 101069644 (LICORNE Project), 101058163 (CRM-Geothermal Project), and 101091715 (FIREFLY Project).
References
Prato M.R.A., Van Vught V., Chayambuka K., Pozo G., Eggermont S., Fransaer J., Dominguez-Benetton X. (2020) Synthesis of material libraries using gas diffusion electrodes. J. Mater. Chem. A, 8:11674-11686. DOI:
10.1039/D0TA00633E.
Martinez Mora O., Pozo G., Leon-Fernandez L.F., Fransaer J., Dominguez-Benetton X. (2023) Synthesis of platinum group metal nanoparticles assisted by CO2 reduction and H2 cogeneration at gas-diffusion electrodes. RSC Sustain., 2023, Accepted Manuscript. DOI: 10.1039/D3SU00046J