Squid inks-derived nanocarbons with unique “shell@pearls” structure for high performance supercapacitors

Abstract Porous carbons derived from biomass are one current hotspot in exploring advanced electrode materials for supercapacitors. In this work, based on nanoparticles from squid inks, an N-doping porous carbons with a unique “shell@pearls” structure has been fabricated through a direct carbonization/activation procedure. Remarkably, a fantastic structural evolution from core-shell, yolk-shell to the porous matrix embedded with small spheres (like pears in shell) has been observed. The as-obtained products exhibit a hierarchical porosity comprised of micro-, meso- and macropores, as well with a large surface area (1957 m 2  g −1 ) and N-doping (2.09%). As the electrode materials for supercapacitors, the “shell@pearls”bio-carbons show the very high capacitance of 329 F g −1 at 0.5 A g −1 and 265 F g −1 at 30 A g −1 and also a superior retention of 99.5% after 10000 cycles at 5 A g −1 .