Direct regeneration of waste LiFePO4 cathode materials with a solid-phase method promoted by activated CNTs

Li Song; Cai Qi; Shuhan Wang; Xukun Zhu; Tong Zhang; Yachao Jin; Mingdao Zhang

doi:10.1016/j.wasman.2022.12.002

Direct regeneration of waste LiFePO₄ cathode materials with a solid-phase method promoted by activated CNTs

Waste Manag. 2023 Feb 15:157:141-148. doi: 10.1016/j.wasman.2022.12.002. Epub 2022 Dec 18.

Authors

Li Song¹, Cai Qi², Shuhan Wang², Xukun Zhu², Tong Zhang², Yachao Jin², Mingdao Zhang³

Affiliations

¹ Institute of Energy Supply Technology for High-end Equipment, Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, Jiangsu Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, School of Environmental Science and Engineering, Nanjing University of Information Science & Technology, Nanjing 210044, Jiangsu, PR China. Electronic address: songli@nuist.edu.cn.
² Institute of Energy Supply Technology for High-end Equipment, Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, Jiangsu Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, School of Environmental Science and Engineering, Nanjing University of Information Science & Technology, Nanjing 210044, Jiangsu, PR China.
³ Institute of Energy Supply Technology for High-end Equipment, Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, Jiangsu Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, School of Environmental Science and Engineering, Nanjing University of Information Science & Technology, Nanjing 210044, Jiangsu, PR China. Electronic address: matchlessjimmy@163.com.

PMID: 36538835
DOI: 10.1016/j.wasman.2022.12.002

Abstract

Annually increasing electric vehicles will undoubtedly end in tremendous amount of waste LiFePO₄ (LFP) batteries. In this work, a highly-efficient and easy-going solid-phase method is proposed for direct regeneration of the waste LFP cathode material (W-LFP). The W-LFP is successfully regenerated via heat treatment with the addition of Li₂CO₃, CNTs and glucose. After activation, the dispersibility of CNTs in water is improved, making it easier to mix well with other materials. Also, the hydroxyl and carboxyl groups on CNTs have a certain degree of reducibility, which is conducive to the reduction of Fe³⁺ to Fe²⁺. After subsequent heat treatment, the three-dimensional conductive network composed of CNTs greatly enhances the conductivity and the ionic diffusion coefficient of LFP, thereby improving its electrochemical performance. Meanwhile, the decay and regeneration mechanisms of LFP are investigated by characterization and electrochemical testing. The regenerated LFP achieves an excellent specific capacity of 155.47 mAh/g at 0.05 C, which is around 99% that of new LFP. Additionally, the costs of main consumption in the regeneration process only account for 33.7% the price of new LFP. This low-cost, high-value-added and solid-phase direct regeneration process is proved to have great economic and energy-saving potential, which is promising for recycling the waste LFP cathode materials.

Keywords: CNTs; Lithium-ion batteries; Recycling; Solid-phase method; Waste LiFePO(4) material.

MeSH terms

Electric Power Supplies*
Electrodes
Ions / chemistry
Lithium* / chemistry
Recycling
Waste Products

Substances

Lithium
Ions
Waste Products