Microwave-assisted pyrolysis of biomass and electrode materials from spent lithium-ion batteries: Characteristics and product compositions

• Published in: Industrial crops and products 2024-12, Vol.222, p.119899, Article 119899
• Main Authors: He, Minyi, Wang, Tianyu, Weng, Tong, Dong, Yuqing, Zhao, Jun, Zhao, Sui, Ma, Wangjing
• Format: Article
• Language: English
• Subjects: Biomass; Microwave absorber; Microwave-assisted pyrolysis; Spent lithium-ion battery recycling
• ISSN: 0926-6690
• DOI: 10.1016/j.indcrop.2024.119899

The development of new energy has promoted the wide application of electric vehicles, but it has also led to a large number of spent lithium-ion batteries (LIBs). Microwave-assisted pyrolysis (MAP) of electrode materials from spent LIBs and biomass has been proven to be an effective method for recovering valuable metals. However, the microwave absorption of these electrode materials, the pyrolysis characteristics of biomass, and their product compositions have not been clearly identified. Herein, the feasibility of several electrode materials from spent LIBs (graphite, LiFePO4, and oxide cathodes) as microwave absorbers in MAP was evaluated by vector net analysis. Furthermore, the MAP characteristics of biomass (cellulose, hemicellulose, lignin, and peanut shell) and these electrode materials were investigated, and relevant mechanisms were proposed through product analysis. The results showed that all electrode materials exhibited medium or strong microwave absorption (tanδε > 0.02) at 2.45 GHz, indicating that they are suitable microwave absorbers for MAP. These spent electrode materials significantly increased the mass loss and yield of gaseous products in the MAP of the above biomass, promoting H2 production and CH4 decomposition. The oxide cathodes could facilitate the dehydration and aromatization of cellulose and hemicellulose, while LiFePO4 and graphite might increase the aromatic content in the liquid products due to their strong reducibility for biomass deoxygenation. Moreover, the characterizations of solid products revealed the phase transitions of spent electrode materials before and after MAP with biomass. This study could provide an experimental and theoretical basis for the application of spent electrode materials from lithium-ion batteries in the microwave-assisted pyrolysis of biomass. [Display omitted] •Electrode materials from spent LIBs applied in MAP of biomass was investigated.•Spent electrodes show medium or strong microwave absorption (tanδε > 0.02).•Spent electrodes promote mass loss and gas yield production in MAP of biomass.•Biomass could also be decent reducing agent for microwave-recovery of spent LIBs.