Fluorinated graphite nanosheets for ultrahigh-capacity lithium primary batteries

• Published in: Rare metals Vol. 40; no. 7; pp. 1708 - 1718
• Main Authors: Yang, Xiao-Xia, Zhang, Guan-Jun, Bai, Bao-Sheng, Li, Yu, Li, Yi-Xiao, Yang, Yong, Jian, Xian, Wang, Xi-Wen
• Format: Journal Article
• Language: English
• Published: Beijing Nonferrous Metals Society of China 01.07.2021; Springer Nature B.V
• Subjects: Active control; Biomaterials; Carbon; Chemistry and Materials Science; Discharge; Electrolytes; Energy; Fluorination; Fluorine; Flux density; Functional groups; Graphite; Lithium; Materials Engineering; Materials Science; Metallic Materials; Nanoscale Science and Technology; Nanosheets; Original Article; Physical Chemistry; Primary batteries; Graphite nanosheets; Soft pack battery; Electrolyte; Carbon fluoride; Primary battery
• ISSN: 1001-0521; 1867-7185
• DOI: 10.1007/s12598-020-01692-y

Traditional fluorinated carbon (CF x ) batteries are greatly limited in their applications mostly because of inferior rate performances, initial voltage delay and low fluorine-to-carbon ratio below one. This work innovatively applies graphite nanosheets (NSs) as carbon source and optimizes the fluorination process at temperature range of 250–400 °C to prepare CF x NSs. Specifically, the edge defects and –CF 2 , –CF 3 perfluorinated functional group active sites are introduced into NSs in the form of covalent/semi-covalent/semi-ionic bonds by adjusting the temperature which also breaks the limit of fluorocarbon ratio to achieve ultra-thin microstructure with high performances. In the battery assembly process, a series of discharge electrolytes are introduced to improve the quality and realize the ultrahigh specific capacity. The optimized CF x -400 °C NSs deliver an excellent specific capacity of 921 mAh·g −1 at a current density of 10 mA·g −1 with a high energy density value of 2210 Wh·kg −1 . Moreover, the new electrolytes are selected which not only serve as electrolytes but also can be loaded on CF x surface for various discharge reactions without affecting the actual battery function. Thus, the lightweight tabs and current collectors are selected to control the loading of active material and injection coefficient. The presented battery design strategy provides a new strategy to achieve an ultrahigh specific energy density of 1116 Wh·kg −1 . Graphical abstract