Facile Synthesis of Graphite-Reduced Graphite Oxide Core–Sheath Fiber via Direct Exfoliation of Carbon Fiber for Supercapacitor Application

Abstract

A graphite-reduced graphite oxide (rGO) core−sheath structured fiber was synthesized through chemical exfoliation of graphitic carbon fiber. The graphitic carbon fiber was oxidized to form a graphite− graphite oxide core−sheath fiber and followed by thermal exfoliation to form a graphite−rGO core−sheath fiber. The core−sheath fiber with a three-dimensionally (3D) structured rGO sheath possesses a high surface area and pore size around 5.5 nm. A two-electrode supercapacitor constructed with this core−sheath fiber-based paper exhibited a high specific capacitance (140 F g −1 at a current density of 1 A g −1), high power density of 45 kW/kg, and good cycling stability (10% capacity loss after 3000 cycles). The surface area normalized capacitance reached as high as 59.4 μF cm −2 , indicating the effective use of surface area. The low equivalent series resistance value of 0.45 ohm in the Nyquist plot indicates an extremely small resistance between the graphite core and rGO sheet sheath. The hierarchical three-dimensional structure enables one to maximize the advantages of both graphite and rGO sheets. The 3D-structured rGO sheets sheath with regular pore structure is favorable for ion diffusion due to its interconnected porous system, while the graphite core provides an electron transport pathway with high conductivity.

CN foam loaded with few-layer graphene nanosheets for high-performance supercapacitor electrodes

“…6b shows the CV curves of the CN-RGO-60 electrode with different scan rates (5-80 mV/s). [58][59][60] The areal capacitance of the CN-RGO/nickel foam electrodes decrease with the increase of scanning rates. 56 This result clearly indicates pseudocapacitance from the Faradaic processes contributes to the charge storage.…”

A Fiber Supercapacitor with High Energy Density Based on Hollow Graphene/Conducting Polymer Fiber Electrode

“…CV curves of the fiber supercapacitors based on HPFs and HCFs with the increasing scan rates from 5 to 100 mV s −1 are shown in Figure S5a,c (Supporting Information), respectively. A rectangular shape profile was shared for both HPF and HCF, indicating a typical behavior of electrochemical double layer capacitor . Compared with the HPF, the CV curves for the HCF can better retain a rectangular shape even at a high scan rate of 100 mV s −1 , which revealed a more rapid charge transport and higher rate performance.…”

“…A rectangular shape profi le was shared for both HPF and HCF, indicating a typical behavior of electrochemical double layer capacitor. [ 21 ] Compared with the HPF, the CV curves for the HCF can better retain a rectangular shape even at a high scan rate of 100 mV s −1 , which revealed a more rapid charge transport and higher rate performance. Note that although the CV curves based on the HPF were slightly deformed with the increasing scan rates due to a relatively low electrical conductivity, a higher capacitive behavior was observed in comparison with the previous reports from the RGO.…”

Advances and prospects of fiber supercapacitors

“…To improve their electrochemical performances, 3D graphene (3D-G) network (GF@3D-G) was developed on the GF fibers ( Figure 5a) using electrochemical method and this 3D framework can partially overcome the problem of restacking and aggregation of graphene sheets [51]. It was reported that this GF had better electric conductivity of 10 S cm -1 .…”