The Role of UV-Vis and ICP-OES Spectroscopy in Lithium-Ion Battery Recycling Methods

Significance of the Topic

The rapid expansion of electric vehicles and energy storage systems has driven a surge in lithium-ion battery (LIB) production. Effective recycling of spent LIBs is critical to secure supply of strategic metals, reduce environmental impact and foster sustainable materials management.

Objectives and Study Overview

This study evaluates a one-step hydrometallurgical recycling process that employs contact-electro-catalytic (CEC) technology to leach Li, Co, Ni and Mn from cathode materials in a single integrated step. UV-Vis spectroscopy and inductively coupled plasma optical emission spectroscopy (ICP-OES) are applied to monitor radical activity, metal dissolution and product purity throughout the workflow.

Methodology

Spent NCM cathode sheets were disassembled, cut into 4×4 cm pieces and subjected to ultrasonic-assisted leaching in 40 mL of 1 M malic acid (or citric acid) with 80 mg SiO₂ catalyst at 80 °C for 6 hours. Radical generation and metal-ion release were tracked in real time by UV-Vis spectroscopy at absorption peaks 390 nm (Ni²⁺), 508 nm (Co²⁺) and 660 nm (Mn²⁺). Radical scavenger tests confirmed the roles of superoxide and hydroxyl radicals. Metal concentrations in leachates were quantified by ICP-OES, calibrated with certified standards.

Instrumentation Used

• Agilent Cary 3500 Multicell Peltier UV-Vis spectrophotometer with Multizone capability
• Agilent Cary UV Workstation software
• Agilent 5800 Vertical Dual View (VDV) ICP-OES for elemental quantification
• Ultrasonic bath (40 kHz, 300 W) with temperature control

Main Results and Discussion

• Optimal conditions (80 mg SiO₂, 1 M malic acid, 80 °C, 6 h, 10 g/L solid-liquid ratio) yielded high leaching efficiencies: Li 99.6%, Co 99.4%, Ni 98.3%, Mn 97.4%.
• UV-Vis monitoring provided insights into radical-driven leaching kinetics, enabling fine-tuning of catalyst dosage, acid concentration and reaction time.
• ICP-OES confirmed low impurity levels (Al, Ca, Mg, Na < 0.03 wt%) and verified the regenerated NCM622 composition (Li:Co:Ni:Mn molar ratio ~10.1:2.1:6:2).

Benefits and Practical Applications

The one-step CEC approach streamlines conventional multistage processes, reducing energy consumption and environmental hazards. Real-time UV-Vis analysis enhances process control, while ICP-OES ensures battery-grade material purity. This method supports scalable, cost-effective recycling to recover critical metals for new LIB production.

Future Trends and Potential Applications

• Integration with continuous flow and automated process control systems.
• Development of alternative green leaching agents and recyclable catalysts.
• Application of AI-driven data analysis to optimize reaction parameters.
• Extension of CEC-assisted recycling to diverse battery chemistries beyond NCM.

Conclusion

The combination of UV-Vis spectroscopy and ICP-OES enables precise, real-time monitoring and quantification in a one-step CEC hydrometallurgical recycling process. This eco-friendly method achieves high recovery rates and battery-grade purity for Li, Co, Ni and Mn from spent cathode materials, advancing sustainable LIB recycling.

References

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2. Jin S et al. A Comprehensive Review on the Recycling of Spent Lithium-Ion Batteries: Urgent Status and Technology Advances. Journal of Cleaner Production, 2022;340:130535.
3. Li H et al. One-Step Green Hydrometallurgical Recycling of Spent Lithium-Ion Batteries' Cathode. Journal of Hazardous Materials, 2025;484:136769.
4. Li H et al. A Contact-Electro-Catalytic Cathode Recycling Method for Spent Lithium-Ion Batteries. Nature Energy, 2023;8:1137-1144.
5. Agilent Technologies. A Practical Guide to Elemental Analysis of Lithium-Ion Battery Materials Using ICP-OES. 2023; Publication 5994-5489EN.