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Research

During my time at Buena Vista University, I embarked on a comprehensive, semester-long independent research study focused on Lithium-Ion Batteries. This rigorous academic endeavor allowed me to delve deeply into the complexities and innovations associated with these critical energy storage devices. The culmination of this research is presented in the paper summarized below, which explores novel methodologies and insights into the recycling of Lithium-Ion Batteries.

A Small-Scale Analysis of Recycling Lithium-Ion Batteries​

Abstract​

As humanity progresses into the 21st century, our reliance on electronic devices has led to the near depletion of the earth's limited lithium supply. Previous attempts to recycle Lithium-Ion batteries were conducted on a large industrial scale with expensive equipment and materials. This study evaluates the feasibility of recycling Lithium-Ion batteries using a single-step hydrothermal relithiation process with consumer-grade materials and cost-effective equipment. The results indicate that small-scale Lithium-Ion battery recycling is achievable with cheaper materials and equipment, suggesting future recycling operations could be more cost-effective for consumers and reduce the overall production cost of Lithium-Ion batteries by utilizing recycled components.

Introduction​

Lithium has been used by humanity for centuries, notably in psychiatry, but its role expanded significantly with the development of the first Lithium-Ion battery by Stanley Whittingham in 1974. Lithium-Ion batteries began to dominate the consumer market in the mid-2000s following the 1996 Battery Act, which restricted mercury and lead battery usage. Despite the popularity of Lithium-Ion batteries, significant recycling efforts did not begin until the early 2010s, focusing on hydrothermal, pyrometallurgical, and direct recycling methods.

Recycling Methods​

  • Pyrometallurgical Recycling: Uses high temperatures to extract materials from Lithium-Ion batteries, which is effective but costly due to high energy consumption.
  • Direct Recycling: Shreds batteries into their base components, creating a "black mass" that is further processed to recover usable materials, though impurities can reduce effectiveness.
  • Hydrothermal Recycling: Uses high temperatures and metal-specific leaching methods, producing liquid waste and traditionally being more expensive.

Experimental Section​

Battery Construction​

Coin cell batteries (CR2032) were chosen for their common use in consumer electronics. The anode was made from a mixture of graphite and PTFE binder, while the cathode was composed of Lithium Manganese Oxide, graphite, and PTFE. These materials were applied to stainless steel mesh, dried, and assembled into batteries using a hand crimper and watch press.

Battery Charging and Testing​

Batteries were charged using a USB coin cell charger and drained in consumer-grade tea lamps. This process was repeated until the batteries could no longer hold a charge, after which the internal materials were set aside for recovery and relithation.

Battery Deconstruction and Relithation​

Batteries were carefully deconstructed, and the internal components were treated in a 2M lithium hydroxide and hydrogen peroxide solution inside a PTFE-lined autoclave at 100°C for 60 minutes. The recovered materials were washed, dried, and reused to create new coin cell batteries, continuing the cycle until the materials were fully spent.

Results and Discussion​

A total of 25 batteries were tested, with the charge capacity measured after each rejuvenation cycle. Data showed a gradual decrease in recovery efficiency, with a notable plateau in the middle cycles, indicating consistent recovery performance. A recovery efficiency drop greater than 60% was considered the threshold beyond which batteries were no longer viable for consumer use. The modified hydrothermal relithation method proved successful and cost-effective for small-scale Lithium-Ion battery recycling.

Conclusion​

The study demonstrates that small-scale hydrothermal relithation for Lithium-Ion batteries is feasible with lower costs using common equipment and reagents. This method could potentially make recycling operations more accessible and reduce production costs by reusing recycled components.

Acknowledgments​

Thanks to Dr. Lisa Mellmann, Dr. Brittney Dinkel, Dr. Melanie Hauser, and the Stine Endowment Committee for their support and guidance.

References​

  • Chen, X., Li, J., Kang, D., Zhou, T., & Ma, H. (2019). A novel closed-loop process for the simultaneous recovery of valuable metals and iron from a mixed type of spent lithium-ion batteries. Green Chemistry, 21(23), 6342–6352.
  • Li, L., Ge, J., Wu, F., Chen, R., Chen, S., & Wu, B. (2010). Recovery of cobalt and lithium from spent lithium ion batteries using organic citric acid as leachant. Journal of Hazardous Materials, 176(1-3), 288–293.
  • Maharaj, F. D., Wu, W., Zhou, Y., Schwanz, L. T., & Marshak, M. P. (2019). Exploring real-world applications of electrochemistry by constructing a rechargeable lithium-ion battery. Journal of Chemical Education, 96(12), 3014–3017.
  • Martineau, R. (2022, February 14). Contaminant identification refines recycling for lithium-ion batteries. NREL.gov.
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  • Whittingham, M. S. (1974). Electrointercalation in transition-metal disulphides. Journal of the Chemical Society, Chemical Communications, (9), 328.
  • Zhou, M., Li, B., Li, J., & Xu, Z. (2021). Pyrometallurgical technology in the recycling of a spent lithium ion battery: Evolution and the Challenge. ACS ES&T Engineering, 1(10), 1369–1382.