Ultrafast microwave synthesis of rambutan-like CMK-3/carbon nanotubes nanocomposites for high-performance supercapacitor electrode materials

Abstract

ordered mesoporous carbon materials show great potential for electric double-layer supercapacitors because of their high specific surface area, designable pore structure, and tunable morphology. However, low graphitic crystallinity nature and poor contact between particles lead to their high inherent resistance, which limits the supercapacitance performance. Herein, we report on a hierarchically rambutan-morphological design of carbon composites with ordered mesoporous carbon as the core and carbon nanotubes as the shell, which significantly improve the electric contact between mesoporous carbon particles and promote the electrochemical performance. By an ultrafast microwave process in a household microwave heater under ambient condition, carbon nanotubes grow out from the pores of ordered mesoporous carbon and are dispersed on its surface like the whiskers of rambutan. As-synthesized ordered mesoporous carbon CMK-3/carbon nanotubes nanocomposites show significantly enhanced specific capacitance (315.6 F•g −1 at 1 A•g −1 , as compared with 172.1 F•g −1 of CMK-3), high rate capability (214.6 F•g −1 at 50 A•g −1), and cycling durability (10,000 cycles, 99.32%). the structural design and microwave synthesis enable a facile preparation of the hybrid ordered mesoporous carbon CMK-3/carbon nanotubes nanocomposites, and show potential for easy and lowcost production of high performance electric double-layer supercapacitors materials. In recent years, conflicts between energy-consuming and global ecology have urged researchers to develop new energy conversion and storage technologies with efficient, environmental-friendly, and sustainable features 1,2. Supercapacitors (also known as Electrochemical capacitors) nowadays increasingly attract the attention of researchers and have been considered as promising devices for future energy storage applications, with the advantages of high power rating compared with batteries, large energy density compared with dielectric capacitors, and excellent charge-discharge stability 3-10. Based on the energy storage mechanism, it can be divided into pseudocapacitors (typically produced with electro-active materials, such as transition metal oxides and conducting polymers), and electric double-layer supercapacitors (EDLCs, with non-redox materials, such as active carbon, porous carbon, etc.). For EDLCs, energy storage is achieved by electrostatic interaction of electron charge in the electrode and adsorbed ions in a Helmholtz double layer at the interface between electrode/electrolyte. Owing to the non-Faradaic process of charging/discharging, carbon-based EDLCs endow high reversibility and stability in aqueous electrolyte 11. However, due to poor electric contact between active material particles and inefficient ion diffusion in the pore structures, relatively low energy density and poor rate performance hinder EDLCs practical applications and further development 12,13. To deal with these challenges, various materials were developed to improve the EDLCs performance, and carbon-based nanost...

Microwave as a Tool for Synthesis of Carbon-Based Electrodes for Energy Storage

“…For improving cycling stability, ordered mesoporous carbon has been combined with CNTs to produce core−shell structured composites. 96 The ordered mesoporous carbon not only acted as the MW absorbing component but also supplied the metal nanoparticles to catalyze the CNT growth. Because of the porous nanoarchitecture (specific surface area, 801 m 2 /g; pore volume, 1.16 cm 2 /g) and synergistic contributions, the composite exhibited superior electrochemical performance, including a cycling stability of 99.32% after 10000 cycles using 1 M H 2 SO 4 aqueous electrolyte solution.…”

“…Besides graphene, other carbon materials like CNTs have also been MW-treated for application in SC electrodes. For improving cycling stability, ordered mesoporous carbon has been combined with CNTs to produce core–shell structured composites . The ordered mesoporous carbon not only acted as the MW absorbing component but also supplied the metal nanoparticles to catalyze the CNT growth.…”

Carbon nanomaterials and their composites for supercapacitors

“…The CNN@N‐PC has a high specific capacitance (244 F/g at 1 A/g), good multiplier performance, and good capacitance retention (92.5% after 5000 cycles) when used as a supercapacitor electrode, indicating potential applications in high‐performance supercapacitors. Yan et al 72 prepared a hierarchical rambutan carbon composite with ordered mesoporous carbon as the core and CNTs as the shell. The synthesized ordered mesoporous carbon CMK‐3/CNTs composites have high specific capacitance (315.6 F/g at 1 A/g), rate performance (214.6 F/g at 50 A/g), and cycle durability (10,000 cycles, 99.32%).…”

Ultrafast materials synthesis and manufacturing techniques for emerging energy and environmental applications

“…The precise control of materials synthesis with ultrafast synthesis techniques, both temporally (ps, fs) and spatially (nm, atomic), can be further improved. 222–226 The majority of reported ultrafast syntheses have synthesis times in the range of microseconds to a few minutes, 227–233 as shown in Fig. 16 and Table 2.…”