Investigation of Capacitive, Electrical, and Mechanical Properties of Graphene Fibers Embedded with Internally Decorated Micropores
摘要
Achieving graphene fibers (GFs) with higher mechanical, electrical and electrochemical properties will resolve the critical challenge for their application in flexible and wearable energy devices. In this report, we synthesized GFs having microsized pores. The uniqueness of these pores is that they are not vacant (like conventional porous materials). Rather, these pores are impregnated with highly conductive nanosized powder. We refer to the GFs having internally decorated pores as 3DG-GFs. These 3DG-GFs demonstrate higher electrical and capacitive properties as compared to conventional GFs with vacant pores. More importantly, despite having internally decorated pores the 3DG-GFs preserve their mechanical strength. Secondly, we optimize the performance of 3DG-GFs by controlling the wet-spinning parameters (e.g., spinneret diameter: 0.35 mm, 0.7 mm, 1 mm and 1.6 mm). It was observed that the distribution and the density of the decorated pores in 3DG-GFs significantly depend upon the spinneret diameter used during wet spinning. These 3DG-GFs were investigated for fiber-based supercapacitors (FSCs) applications. The optimized 3DG-GF resulted in the volumetric capacitance of 135.95 Fcm−3 at the current density of 0.3 Acm−3. The corresponding energy and power densities were calculated to be 6.3 mWhcm−3 and 120.5 mWcm−3, respectively. In terms of electrical and mechanical properties, the 3DG-GF demonstrated the conductivity of 9.1(103) Sm−1, mechanical strength of 42 MPa and strain elongation of 18%. Thirdly, we highlight that heating the 3DG-GF electrodes between 180 and 900 °C has adverse effects on the electrical, mechanical and capacitive properties because the high temperature physically damages the hierarchical structures of decorated pores.