Search

Coal-based 3D hierarchical porous carbon aerogels (3D HPCAs) has been successfully fabricated from a freeze-drying method and with subsequent of calcination process, using coal oxide as carbon precursors, and PVA as both cross-linking agent and sacrifice template. The 3D HPCAs, using as electrode materials for supercapacitors, display outstanding electrochemical performance. The optimal sample (HPCAs-0.4-800) presents a high specific capacitance of 260 F g−1 at 1 A g−1, and exhibits considerable rate capability with the retention of 81% at 10 A g−1. Notably, HPCAs-0.4-800 shows an excellent cycling stability with 105% of the capacitance retention after 50000 cycles at 10 A g−1, attributing to its unique hierarchical porosity, high surface area up to 1303 m2 g−1, and improved conductivity. This work offers a promising route to synthesize coal-based porous carbon aerogels electrode materials for supercapacitors. [ABSTRACT FROM AUTHOR]

Elm seed-like nickel sulfide nanosheets grown on the surface of coal-based carbon fibers are reasonably constructed and prepared by a multistep transformation approach. The silica/coal-based carbon fibers are obtained via electrospinning a water/N,N-dimethylformamide two-phase solution of oxidized coal, polyvinyl alcohol and tetraethyl orthosilicate, followed by carbonization. The elm seed-like nickel silicate nanosheets formed by many small nickel silicate nanosheets are deposited on the surface of the coal-based carbon fibers, and then transformed into nickel sulfide with a similar morphology by chemical conversion. Benefiting from the large specific surface area and unique novel structure of the obtained sample, the obtained binder-free electrode exhibits a high specific capacitance of 635.1 F g−1 at 1 A g−1 and delivers a good capacitance retention of 96.4% over 5000 cycles, which are much higher than those of the reference sample without tetraethyl orthosilicate (298.5 F g−1 and 87.7%, respectively). This design idea offers a new strategy for the synthesis of elm seed-like nickel sulfide nanosheet/coal-based carbon fiber composites as flexible electrode materials. [ABSTRACT FROM AUTHOR]

Vanadium nitride is highly desirable for their good electrochemical performance and wide work potential window, but they are cramped practical applications in supercapacitors due to poor cycling stability. Herein a combined strategy is exploited to fabricate coralloid-like nanostructure vanadium nitride/carbon (VN/C) via a facile hydrothermal method. The structural characterization displayed that nano-VN was uniformly distributed in the carbon scaffold materials to improve the electrode behavior. Those composites exhibited a wide voltage window of −1.1 to 0 V with a specific capacitance of 385 F g−1 at 1 A g−1, and exceptional cycling stability (88.9% retention after 10000 cycles). The two-electrode system based on VN/C electrodes obtains a high energy density of 24.2 Wh kg−1 at a power density of 1050 W kg−1. The device also shows perfect cycling stability with 93.3% capacitance retention after 10000 cycles. The coralloid-like VN/C electrode materials can be used in practical applications of the high-performance energy storage device. A facile method is designed to obtain coralloid-like vanadium nitride/carbon nanocomposites for high-performance and long-life supercapacitors. Image 1 • A facile hydrothermal method was used to fabricate coralloid-like nanostructure vanadium nitride/carbon nanocomposites. • The coralloid-like VN/C nanocomposites exhibit a high specific capacitance of 385 F g−1 at 1 A g−1. • The electrode exhibits extraordinary cycling stability with 88.9% capacitance retention after 10000 cycles. [ABSTRACT FROM AUTHOR]