Credit: Energy Storage Materials (2025). DOI: 10.1016/j.ensm.2025.104646

A research team affiliated with UNIST has unveiled an innovative recycling technology capable of recovering more than 95% of nickel and cobalt from waste batteries with a purity exceeding 99%. This advanced method addresses the limitations of conventional wet recycling processes, which often involve complex chemical procedures and generate large volumes of harmful wastewater. The new approach promises a more sustainable, high-efficiency solution that could transform the battery recycling industry.

Professor Kwiyong Kim and his research team from the Department of Civil, Urban, and Earth Environmental Engineering successfully demonstrated the selective electrochemical separation process utilizing a multifunctional special solvent. This breakthrough, published in Energy Storage Materials, enables efficient recovery of nickel and cobalt from spent batteries through a single, environmentally friendly step.

Waste batteries are often called “urban mines” due to their abundance of critical metals, such as nickel, cobalt, and manganese. However, the coexistence of multiple metals makes their separation challenging. Conventional methods rely on strong acids, like sulfuric acid and chemical extractants, which produce hazardous wastewater and involve multi-stage, energy-intensive processes.

The new electrochemical process minimizes chemical usage and wastewater production while enhancing both purity and recovery efficiency. By applying a controlled voltage to a liquid mixture containing crushed battery material, metal ions are selectively deposited as solid metals. This technique leverages the different voltages at which each metal ion reduces, enabling precise separation.

Specifically, the team overcame the common challenge of simultaneous co-deposition of nickel and cobalt—usually occurring at similar voltages—by employing a specialized co-solvent. Ethylene glycol in the solvent preferentially binds with nickel ions, while chloride ions stabilize cobalt as tetrachlorocobaltate complexes. This differential coordination shifts the reduction voltages, allowing nickel to be deposited at –0.45 V and cobalt at –0.9 V, effectively separating the two metals.

An added advantage of this process is the natural formation of chlorine by-products, which selectively dissolve cobalt impurities. This in-situ self-purification enhances the purity of recovered nickel without the need for additional refining steps. The chlorine-containing solution can be safely vented, as it forms inert ions, and the solvent’s hydrochloric acid content can be regenerated and reused, minimizing environmental impact.

When applied to real NCM (Nickel-Cobalt-Manganese) battery leachates, the process achieved recovery rates exceeding 95%, with separation purity surpassing 99.9% for both nickel and cobalt. Notably, the special solvent maintained performance over at least four reuse cycles, further reducing waste.

Professor Kim stated, “By overcoming the long-standing trade-off between purity and recovery rate in electrochemical separation, our method offers a sustainable and cost-effective solution. It minimizes chemical use and wastewater, contributing to a more sustainable battery recycling ecosystem.”

More information: Seongmin Choi et al, Highly selective and near-complete electrochemical recovery of cobalt and nickel from spent batteries through multifunctional deep eutectic solvent, Energy Storage Materials (2025). DOI: 10.1016/j.ensm.2025.104646

Citation: Recycling technology achieves 99% purity of nickel and cobalt extracted from waste batteries (2025, November 10) retrieved 10 November 2025 from https://techxplore.com/news/2025-11-recycling-technology-purity-nickel-cobalt.html

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