Fluorinated N,P co-doped biomass carbon with high-rate performance as cathode material for lithium/fluorinated carbon battery

• Published in: Rare metals 2024-07, Vol.44 (1), p.110-120
• Main Authors: Yan, Ke, Zou, Yan, Bao, Liang-Xue, Xia, Qi, Meng, Ling-Yi, Lin, Hai-Chen, Chen, Hui-Xin, Yue, Hong-Jun
• Format: Article
• Language: English
• Subjects: Basal plane; Biomass; Carbon; Commercialization; Crystal defects; Density functional theory; Diffusion barriers; Discharge; Doping; Electrode materials; Fluorination; Functional groups; Lithium; Melamine; Phytic acid; Porous materials
• ISSN: 1001-0521; 1867-7185
• DOI: 10.1007/s12598-024-02894-4

Lithium/fluorinated carbon (Li/CFx) batteries are greatly limited in their applications mostly due to poor rate performances. In this study, N,P co-doped biomass carbon was synthesized using melamine and phytic acid as doping sources, and the resulting product was then utilized as a precursor for CFx. The resulting fluorinated biomass carbon has a high degree of fluorination, exceeding the specific capacity of commercial fluorinated graphite while also demonstrating exceptional performance at high discharge rates. During the fluorination process, N,P-containing functional groups were removed from the crystalline lattice in the basal plane. This facilitates the formation of a defect-rich carbon matrix, enhancing the F/C ratio by improving the fluorinated active sites and obtaining more highly active semi-ionic bonds. Additionally, the abundant defects and porous structure promote Li+ diffusion. Density functional theory calculations indicated that doping modification effectively reduces the energy barrier for Li+ migration, enhancing Li+ transport efficiency. The prepared CFx delivers material with a maximum specific capacity of 919 mAh·g−1, while maintaining a specific capacity of 702 mAh·g−1 at a high discharge current density of 20C (with a capacity retention rate of 76.4%). In this study, fluorinated N,P co-doped biomass carbon, exhibiting ultrahigh capacity and high-rate performance, was prepared for the first time, which can potentially advance the commercialization of CFx.