Spent Lithium-Ion Batteries Transformed into Powerful Catalysts That Destroy Toxic Air Pollutants

Every year, hundreds of millions of lithium-ion batteries reach the end of their working lives, and most of the valuable materials locked inside them are never recovered. At the same time, factories, paint shops and refineries continue to pump volatile organic compounds, or VOCs, into the air — hazardous chemicals such as benzene that are linked to cancer, smog formation and serious respiratory disease. A new study published in Catalysis Letters now connects these two problems with a single, elegant solution: researchers have shown that the manganese-rich cathode material harvested from spent batteries can be converted, in a matter of seconds, into highly active catalysts that destroy benzene at remarkably low temperatures. The finding, led by Xuan Wang and colleagues at Hebei University of Technology working with Cairong Gong of Tianjin University, points toward a circular-economy route for both battery waste and industrial air pollution control.

The material at the heart of the work is a lithium manganese oxide cathode with the formula Li1.27Mn1.73O4, a composition typical of spent lithium-ion batteries from the lithium-manganese-oxide family. Instead of dismantling the chemistry and rebuilding the catalyst from purified metal salts — the conventional, energy-hungry approach — the team treated the spent cathode powder itself as the precursor. After removing the residual lithium using a deep eutectic solvent system based on choline chloride and lactic acid, they were left with a manganese-rich oxide framework ready to be activated. This lithium-extraction step proved critical, because the removal of lithium ions from the host lattice destabilizes the crystal structure and opens the door to defect formation on a scale that ordinary synthesis routes rarely achieve.

The second ingredient in the recipe is the heating method. Rather than ramping up a muffle furnace over hours, the researchers employed flash Joule heating, a technique in which a large electrical current is passed directly through the sample, generating intense heat within the material itself in seconds. The team systematically varied the applied current, producing a series of catalysts labeled FMn-aA, where the current ranged up to 25 amperes. For comparison, they also prepared catalysts from the same battery-derived material using conventional muffle-furnace calcination, and from analytical-grade metal salts processed both ways. This four-way comparison allowed them to isolate the individual and combined effects of the precursor source and the heating regime.

The results were striking. The optimized catalyst, designated FMn-25A, achieved more than 90 percent conversion of benzene at only 208 degrees Celsius. In the catalytic oxidation of VOCs, the temperature at which 90 percent of the pollutant is converted — known as T90 — is a key benchmark, because lower operating temperatures translate directly into lower energy costs and reduced risk of unwanted byproduct formation. Manganese oxides are well known catalysts for this chemistry, but reaching such low light-off temperatures typically requires careful doping, composite formation or noble metal promotion. Here, the researchers obtained the performance simply by choosing a waste-derived precursor and heating it in the right way.

The reason for the enhanced activity lies in the defect chemistry of the material. Detailed characterization combining X-ray diffraction, electron microscopy, X-ray photoelectron spectroscopy, hydrogen temperature-programmed reduction, oxygen temperature-programmed desorption and electron paramagnetic resonance showed that flash Joule heating combined with lithium-ion removal generated an unusually high density of oxygen vacancies — atomic-scale holes in the oxide lattice where an oxygen atom is missing. These vacancies are not passive imperfections. They are chemically active sites that change the electronic environment of neighboring manganese atoms, making the lattice easier to reduce and reoxidize, and they create anchoring points where gas-phase oxygen can adsorb and be converted into reactive oxygen species.

To trace exactly how benzene is destroyed on these surfaces, the team turned to in-situ diffuse reflectance infrared Fourier transform spectroscopy, or DRIFTS. This technique monitors the chemical species present on a catalyst surface while the actual reaction is running. The spectra revealed that the abundant oxygen vacancies promoted the formation of active oxygen species, which then attacked the benzene ring and its partially oxidized intermediates, accelerating the entire oxidation cascade toward complete conversion to carbon dioxide and water. In essence, the vacancies act as continuous suppliers of the reactive oxygen that drives the chemistry, explaining why the defect-rich battery-derived catalysts outperformed their conventionally prepared counterparts, including the CMn-MS sample made from metal salts in a muffle furnace and the salt-derived catalyst heated by flash Joule heating.

The study also underscores a broader lesson about how synthesis conditions shape catalytic materials. Conventional furnace calcination proceeds slowly and at relatively moderate temperatures, allowing the oxide lattice to relax into well-ordered, defect-poor configurations. Flash Joule heating, by contrast, delivers an extreme thermal shock followed by rapid cooling, freezing in a metastable, defect-rich structure. When applied to a lithium-depleted battery cathode — a lattice already destabilized by the extraction of lithium ions — this thermal shock produces exactly the kind of oxygen-deficient, highly reducible surface that low-temperature oxidation catalysis demands. The finding aligns with a growing body of literature on rapid Joule heating for catalyst preparation, which has shown that ultrafast thermal processing can create single-atom sites, defective graphenes and nanostructured electrocatalysts that are difficult or impossible to obtain through conventional routes.

The environmental logic of the approach is twofold. On the waste side, recycling strategies for spent lithium-ion batteries have so far concentrated on recovering lithium, cobalt and nickel from high-value ternary cathodes, while manganese-based cathodes have attracted less commercial attention and often end up in lower-value applications or landfill. Converting this material directly into environmental catalysts gives it a productive second life without demanding the purity levels required for new battery manufacturing. Earlier work by the same research group and others has already demonstrated that spent battery materials can serve as precursors for ammonia-selective catalytic reduction catalysts and for catalysts that simultaneously remove nitrogen oxides and VOCs. The present study extends that concept to lithium manganese oxide chemistry and, crucially, combines it with ultrafast electrified heating rather than energy-intensive furnace treatment.

On the pollution side, catalytic oxidation is one of the most effective technologies for destroying VOC emissions, but its industrial adoption has been constrained by the high temperatures — often above 300 degrees Celsius — that conventional catalysts require to achieve complete conversion. Every hundred degrees saved is a meaningful cut in operating energy and cost, particularly for dilute emission streams from painting, printing, petrochemical and smelting operations, sectors that are significant VOC sources and the focus of tightening regulation. A catalyst that reaches 90 percent benzene conversion at 208 degrees Celsius, made from waste rather than fresh chemicals and activated without prolonged furnace heating, addresses the economic and sustainability dimensions of the problem simultaneously. The authors describe the work as a sustainable strategy for green industrial VOC abatement, and the research was supported by China’s National Science and Technology Major Project on regional environmental improvement in the Beijing-Tianjin-Hebei area.

Significant steps remain before the concept reaches industrial deployment. Real emission streams contain water vapor, sulfur compounds and mixtures of VOCs that can poison or deactivate catalysts, and the long-term stability of a defect-rich structure under continuous operation must be demonstrated. Scaling flash Joule heating from laboratory powder samples to the throughput of a working air-cleaning unit is another engineering challenge, although the process is inherently fast and electrically driven, which favors energy efficiency and compatibility with renewable power. Nevertheless, the study offers a compelling proof of principle: the defective, highly reactive materials that catalyst designers usually struggle to engineer can emerge naturally — and almost instantly — from the wreckage of yesterday’s batteries. In turning one environmental liability into the cure for another, the work captures the kind of cross-cutting chemistry that may define the next generation of sustainable pollution control.

Subject of Research: Flash Joule heating fabrication of defect-rich manganese oxide catalysts from spent lithium-ion battery cathodes for low-temperature VOC oxidation

Article Title: Flash Joule Heating–Driven Fabrication of Defect-Rich Catalysts Derived from Spent Li1.27Mn1.73O4 Batteries for Low-Temperature VOCs Oxidation

Article References: Wang, X., Zheng, Y., Guo, H. Y., Duan, X. H., Gong, C., & Xue, G. (2026). Flash Joule Heating–Driven Fabrication of Defect-Rich Catalysts Derived from Spent Li1.27Mn1.73O4 Batteries for Low-Temperature VOCs Oxidation. Catalysis Letters, 156(10), Article 283. https://doi.org/10.1007/s10562-026-05527-w

Image Credits: AI Generated

DOI: 10.1007/s10562-026-05527-w

Keywords: flash Joule heating, oxygen vacancies, spent lithium-ion batteries, benzene catalytic oxidation, manganese oxides, volatile organic compounds, low-temperature catalysis, lithium-ion removal, deep eutectic solvents, DRIFTS, catalyst recycling, VOC abatement