Efficient methods for recycling cathodes of spent lithium-ion batteries

• Author / Creator

  Zhang, Nianji

• The ever-growing market share of electrical transportation and energy storage stations has led to a demand surge for lithium-ion batteries (LIBs). Despite their popularity in global energy storage market, an efficient, sustainable and green method that can recycle spent LIBs is also in active exploration. Currently, recycling methods that destructively extract valuables from spent cells, pyro- and hydro-metallurgy, have demonstrated their feasibility at industrial scale, yet both approaches are criticized of generation of undesired environmental concerns. Both metallurgical methods aimed at extracting valuable metals only, however, suffer from the market trend shifting towards cobalt-poor and even cobalt-free chemistry. Recently guided by circular and green economy, alternative innovative strategies are emerging in order to achieve an “closed-loop” recycling of spent LIBs. What is interesting in these strategies is a complete recovery of the pristine structure and functionality of cathode materials in non-destructive methods. Despite the great promise and advantages of the direct recovery method in terms of simplicity, low energy consumption and low stress on the environment, it is still inadequate and ineffective to process obsolete cathodes, such as LiCoO2 and NCM111, to meet the current market. In view of this, another nondestructive method, upcycling, is developed, which aims at either recycling spent cathodes with increased functionality for new applications, or regenerating cathodes with increased performance. This thesis includes fundamental development of cathode recycling strategies, and focuses on developing efficient and effective upcycling method.
  This thesis starts with a literature review (Chapter 1) on necessary pretreatment process and recent advances in current four recycling methods, where their ascendancy, challenges, and perspectives are also discussed. Then, the focus of this thesis is extended to a research attempt on testing the feasibility of upcycling methods (Chapter 2). In this research, a 5% LiMn0.75Ni0.25O2 coating is manufactured on spent LiCoO2 cathode material through a modified hydrothermal treatment coupled with a short annealing. With this coating, the upcycled cathode shows a capacity of 160.23 mAh/g with a capacity retention of 91.2% after 100 cycles which are much improved comparing with pristine LiCoO2.
  

• Subjects / Keywords

  • Recycling
  • Upcycling
  • Spent lithium-ion batteries
  • Direct recycling

• Graduation date

  Spring 2022

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/r3-3rp1-0b95

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.