Free-standing fluorine and nitrogen co-doped graphene paper as a high-performance electrode for flexible sodium-ion batteries

• Published in: Carbon (New York) Vol. 116; pp. 338 - 346
• Main Authors: An, Haoran, Li, Yu, Gao, Yi, Cao, Chen, Han, Junkai, Feng, Yiyu, Feng, Wei
• Format: Journal Article
• Language: English
• Published: New York Elsevier Ltd 01.05.2017; Elsevier BV
• Subjects: Anodes; Battery cycles; Bicycles; Chemical bonds; Chemical synthesis; Defects; Doping; Electrical resistivity; Electrochemical analysis; Electrodes; Electron transport; Fluorine; Graphene; Interlayers; Nitrogen; Rechargeable batteries; Sodium-ion batteries; Tensile strength; Wearable technology
• ISSN: 0008-6223; 1873-3891
• DOI: 10.1016/j.carbon.2017.01.101

Free-standing fluorine and nitrogen co-doped graphene paper (FNGP) electrodes were synthesized by a solvothermal process as potential anodes for flexible sodium-ion batteries (SIBs). F and N co-doping in the graphene frameworks simultaneously increases structural defects, provides active sites, and enlarges the graphene interlayer distance; these properties are favourable for improving Na+ storage capabilities. In particular, the semi-ionic CF bonds in FNGP, prepared at a solvothermal temperature of 120 °C, enhance electrical conductivity and hence facilitate electron transport in the electrode. Therefore, this FNGP anode delivers a reversible capacity of 203 mAh g−1 (114.9 mAh cm−3) at 50 mA g−1 after 100 cycles and exhibits superb long-cycling stability with a reversible capacity of 56.3 mAh g−1 at 1 A g−1 after 5000 cycles. In addition, the excellent tensile strength (43.5 ± 1.8 MPa) and maintained electrochemical performance of the FNGP anode in the bent state demonstrate the promise of this electrode for applications in flexible, wearable and rolled-up devices. [Display omitted]