Abstract
Li/CFx is one of the highest-energy-density primary batteries; however, poor rate capability hinders its practical applications in high-power devices. Here we report a preparation of fluorinated graphene (GFx) with superior performance through a direct gas fluorination method. We find that the so-called “semi-ionic” C-F bond content in all C-F bonds presents a more critical impact on rate performance of the GFx in comparison with sp2 C content in the GFx, morphology, structure, and specific surface area of the materials. The rate capability remains excellent before the semi-ionic C-F bond proportion in the GFx decreases. Thus, by optimizing semi-ionic C-F content in our GFx, we obtain the optimal x of 0.8, with which the GF0.8 exhibits a very high energy density of 1,073 Wh kg−1 and an excellent power density of 21,460 W kg−1 at a high current density of 10 A g−1. More importantly, our approach opens a new avenue to obtain fluorinated carbon with high energy densities without compromising high power densities.
Highlights
Fluorinated carbon (CFx) possesses a very high theoretical energy density (2,180 Wh kg−1 when x equals 1 for fluorinated graphite) as a cathode material for primary lithium batteries, has been strongly desired in many civil and military applications that require a long service-life, wide range of operating temperatures, as well as high energy densities and reliability
Coating of highly conductive materials, such as carbon, polypyrrole, and polyaniline on the surface of carbon fluorides is helpful to improve the rate capability (Zhang Q. et al, 2010; Groult et al, 2011; Li et al, 2016); for example, a graphite fluoride coated with polyaniline delivered an energy density of about 1,200 Wh kg−1 with power density higher than 10,000 W kg−1 at current rate of 8C (Li et al, 2016)
It is well known that the fluorine content in fluorinated carbon significantly affects the electrochemical performance
Summary
Fluorinated carbon (CFx) possesses a very high theoretical energy density (2,180 Wh kg−1 when x equals 1 for fluorinated graphite) as a cathode material for primary lithium batteries, has been strongly desired in many civil and military applications that require a long service-life, wide range of operating temperatures, as well as high energy densities and reliability. With an optimal semi-ionic C-F bond ratio, our GFx showed extraordinary performance with a power density of 21,460 W kg−1 and an energy density of 1,073 Wh kg−1 when the x in GFx equals 0.8, superior to most of the previously reported fluorinated carbons (Mickelson et al, 1998; Lam and Yazami, 2006; Shulga et al, 2007; Yazami et al, 2007; Zhang W. et al, 2010; Fulvio et al, 2011; Groult et al, 2011; Guérin et al, 2012; Damien et al, 2013; Meduri et al, 2013; Sun et al, 2014; Zhao et al, 2014; Feng et al, 2016; Li et al, 2016; Wang et al, 2016). Discharge tests were performed at various currents with a cutoff voltage of 1.5 V by a LAND CT2001A battery test system at 25◦C
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
