Pitch-based porous aerogel composed of carbon onion nanospheres for electric double layer capacitors

• Published in: Carbon (New York) 2018-10, Vol.137, p.304-312
• Main Authors: Liu, Kun-lin, Jiao, Miao-lun, Chang, Pan-pan, Wang, Cheng-yang, Chen, Ming-ming
• Format: Article
• Language: English
• Subjects: Aerogels; Batteries; Capacitance; Carbon; Catalysis; Chemical composition; Deionization; Design optimization; Electric double layer; Electrical resistivity; Electrodes; Energy storage; Flux density; Hydrogen storage; Hydrogen-based energy; Morphology; Nanospheres; Organic chemistry; Pore size distribution; Porosity; Sol-gel processes; Structural hierarchy; Supercapacitors
• ISSN: 0008-6223; 1873-3891
• DOI: 10.1016/j.carbon.2018.05.038

The morphology, pore structure and chemical composition of materials are key to supercapacitor performances. To design reasonable morphology and optimize pore size distribution of materials, we employ a combination of sol-gel method and chemical activation with an aid of freeze drying to prepare a three dimensional hierarchical porous pitch-based aerogel (3DHPPA). The aerogel owns hierarchical porous structure ranging from 0 to 100 nm, high specific surface area of 2220 m2 g−1 and is made up of carbon onion-like nanospheres of 20–40 nm with enough electric conductivity (103.2 S m−1). In view of the unique architecture, the supercapacitor assembled from 3DHPPA with the area density of 8.9 mg cm−2 exhibits high specific capacitance of 157 F g−1 at 50 mA g−1, excellent rate performance (95 F g−1 at 10 A g−1), considerable energy density of 24.2 Wh kg−1 at 6.75 kW kg−1 (voltage range of 2.7 V) and outstanding cycling life with 81.5% capacitance retention at 2 A g−1 after 8000 cycles in 1 M TEABF4/PC electrolyte. Furthermore, the formation mechanism of the 3DHPCA is elucidated in this work. The simple, feasible and low-cost strategy makes 3DHPPA applicable in other fields of energy storage, hydrogen storage, capacitive deionization and catalysis. [Display omitted]