A second life for lithium-ion batteries could propel future space missions
The use of lithium-ion batteries has doubled globally in the past four years, contributing to the growing amount of hazardous battery waste. This increase underlines the urgent need for more effective recycling solutions. Scientists from several Polish research institutions, including the Bydgoszcz University of Science and Technology (PBS), the Institute of Basic Technological Research of the Polish Academy of Sciences, the Institute of Physical Chemistry of PAS in Warsaw, and the University of Science and Technology of Wroclaw, have introduced a promising approach in the journal ‘ChemElectroChem’.
The research focused on carbon materials extracted from the electrodes of spent lithium-ion batteries (LIBs). The team used an acid leaching process to recover valuable metals from these electrodes. Depending on the experimental conditions, the extracted carbon materials retained traces of metals such as cobalt, which is often used in catalysis. The aim was to repurpose these materials for use in catalytic processes, with particular emphasis on the production of hydrogen peroxide.
“Hydrogen peroxide is one of the fundamental chemical molecules, essential for many industries. Large-scale production of this substance typically requires high pressures and temperatures, expensive catalysts and various toxic electrolytes. Our focus was on developing a more environmentally friendly production method. hydrogen peroxide: specifically an electrochemical approach using catalysts derived from spent lithium-ion batteries,” explains Dr. Eng. Magdalena Warczak (PBS), project leader and lead author.
The team’s electrochemical tests showed that carbon nanostructures and cobalt extracted from the batteries showed catalytic properties for the oxygen reduction reaction. However, these properties were affected by the composition and structure of the sample, which were determined by the types of etching baths used to clean the extracted electrodes.
“For potential future applications, the crucial finding is that, based on data collected from experiments with a rotating electrode, we were able to determine the number of electrons involved in the reduction of a single oxygen molecule. The electrochemical reduction of oxygen can occur with four or two electrons. In the case of four electrons, water is produced, but with two electrons we obtain the desired hydrogen peroxide. In all the samples we tested, we observed the reduction of two electrons,” explains Dr. Warczak out.
To ensure accuracy, the measurements were repeated with battery powders suspended between two immiscible liquids, eliminating any influence of the glassy carbon electrode. The oxygen reduction reaction occurred spontaneously at the interface of these liquids, with the organic liquid containing decamethylferrocene, an electron donor. These experiments confirmed that all samples catalyzed the production of hydrogen peroxide, with concentrations measured by a scanning electrochemical microscope showing levels one to two orders of magnitude higher than those in systems without battery waste.
“Lithium-ion batteries are generally viewed as only a secondary source of carbon materials, mainly graphite, and metals such as lithium, cobalt or nickel. Meanwhile, our group’s findings clearly demonstrate that battery waste can catalyze the reduction of oxygen to hydrogen peroxide. and in the future this could lead to its use in the production of this important chemical compound,” concludes Dr. Warczak.
Hydrogen peroxide, commonly found in pharmacies at a concentration of 3% for disinfecting wounds, has a range of industrial applications. Solutions with concentrations of up to 15% are used in household cleaning products and cosmetics, while concentrations of around 30% are vital in industries such as chemical manufacturing, pulp and paper, textiles, electronics and food processing. Hydrogen peroxide also serves as an oxidizer for fuels, including rocket fuels. In the 1940s it was first used in early rockets that could reach space. Recently, hydrogen peroxide in concentrations of more than 98% powered a suborbital rocket built by the Lukasiewicz Institute of Aviation in Warsaw.
Research on the production of hydrogen peroxide from spent lithium-ion batteries, initially funded by a SONATA grant from the Polish National Science Center, will continue with a focus on improving the efficiency of electrochemical reactions for industrial use. The team also plans to investigate four-electron reduction for potential applications in fuel cells.
Research report:Insights into the high catalytic activity of Li-ion battery waste towards oxygen reduction to hydrogen peroxide
