Engineering Kinetics-Favorable Carbon Sheets with an Intrinsic Network for a Superior Supercapacitor Containing a Dual Cross-linked Hydrogel Electrolyte

Abstract

Despite the physicochemical advantages of two-dimensional (2D) carbons for supercapacitors, the inappropriate texture within 2D carbon materials suppresses the charge storage capability. Reported here are heteroatom-rich carbon sheets with the overall network engineered by molecular structure modulation and subsequent chemical activation of a three-dimensional (3D) cross-linked polymer. The 3D-to-2D reconstruction mechanism is unveiled. The architecture with a large active surface, fully interpenetrating and conductive network, and rich surface heteroatoms relieves well the ionic diffusion restriction within thick sheets and reduces the overall resistance, exhibiting fast transport kinetics and excellent stability. Indeed, high gravimetric capacitance (281.1 F g–1 at 0.5 A g–1), ultrahigh retention rate (92.5% at 100 A g–1), and impressive cyclability (89.7% retention after 20 000 cycles) are achieved by this material. It also possesses a high areal capacitance of 3.56 F cm–2 at 0.5 A g–1 under a high loading of 25 mg cm–2. When coupled with the developed dual cross-linked hydrogel electrolyte (Al-alginate/poly­(acrylamide)/sodium sulfate), a quasi-solid-state supercapacitor delivers an energy density of 28.3 Wh kg–1 at 250.1 W kg–1, which is significantly higher than those of some reported aqueous carbon-based symmetric devices. Moreover, the device displays excellent durability over 10 000 charge/discharge cycles. The proposed cross-linked polymer strategy provides an efficient platform for constructing dynamics-favorable carbon architectures and attractive hydrogel electrolytes toward improved energy supply devices.

Silica-Assisted Controlled Engineering of Nitrogen-Doped Carbon Cages with Bulges for High-Performance Supercapacitors

“…In particular, the capacitance of CCB-70 is higher than many other carbonaceous electrode materials reported by previous research studies, such as hierarchical porous carbon (360 F g −1 at 1 A g −1 ), 42 nanoporous carbons with highly tunable porosity (320 F g −1 at 0.5 A g −1 ), 43 nitride coated with a thin carbon shell (160 F g −1 at 0.25 A g −1 ), 44 MOF-derived carbon (236 F g −1 at 0.5 A g −1 ), 45 N-doped carbon aerogels (300 F g −1 at 0.5 A g −1 ), 46 ZIF-8/polyvinylpyrrolidone-derived porous carbon (160 F g −1 at 0.1 A g −1 ), 47 macroporous carbon sponge (350 F g −1 at 0.5 A g −1 ), 48 and carbon sheets with an intrinsic network (281 F g −1 at 0.5 A g −1 ). 49 The outstanding performance of CCB may be that the unique structure and bulge surface of carbon nanocages increase the contact area between ions and electrolytes.…”

Nitrogen-Doped Porous Carbon Derived from Cellulose Microfibers of Rice Straw for High-Performance Electrodes of Supercapacitors

“…The absorption peak at 1141 cm −1 can be ascribed to C−O bonds, 29,30 indicating that the carbon materials contain oxygenic functional groups.…”

“…The weak peaks ascribed to C–H stretching in the range of 2800–3000 cm –1 reveal that the carbonization resulted in great losses of organic components. The absorption peak at 1141 cm –1 can be ascribed to C–O bonds, , indicating that the carbon materials contain oxygenic functional groups.…”

Highly active N, S Co-Doped Ultramicroporous Carbon for High-Performance Supercapacitor Electrodes

“…Carbon materials, including activated carbon, carbon nanotubes and carbon aerogels, are mainly applied as EDLC electrodes due to their high specific surface area and designable pore structure [10][11][12][13]. For microporous carbons, the <1 nm pores have a relationship with an anomalous increase in electrochemical performance [14,15].…”