Unique elastic N-doped carbon nanofibrous microspheres with hierarchical porosity derived from renewable chitin for high rate supercapacitors

Chitin derived from discarded seafood waste (crab and shrimp shell) is a naturally abundant resource, but its difficult dissolubility limits the processing and applications. Herein, we prepared nanofibrous microspheres by using chitin solution dissolved in NaOH/urea aqueous solvent at low temperature, and subsequently fabricated the novel elastic nitrogen-doped carbon microspheres by pyrolyzing the chitin microspheres. Interestingly, the carbon microspheres were consisted of robust cross-linked nanofibers and displayed interconnected nanofibrous framework architecture, named as CNFF. The CNFF microspheres showed unique elasticity, excellent compression behaviors, and the morphology recovered completely over 5 cyclic compression at strain 75%. Moreover, the carbon microspheres exhibited an outstanding rate capability with a capacitance retention of ~50% when increase the scan rate from 5 mV/s to 10,000 mV/s as well as good cycling stability for supercapacitor applications, as a result of their hierarchical porosity, stable 3D interconnected mesh structure and ultrahigh specific surface area (over 1000 m2/g). Particularly, in the organic electrolyte, the highest deliverable energy density reached up to 58.7 Wh/kg. This work opened up a completely new and green avenue for constructing high performance carbon-based material with elasticity from biomass waste, showing promising application in the energy storage field.