Self-Grown 1D/2D Ni(OH)2 nanofiber/nanosheet on corn stigma-derived carbon for high-performance hybrid supercapacitors

Enhancing the energy density of supercapacitors is of great scientific and technological importance, producing a larger energy density than traditional symmetrical carbon supercapacitors. Herein, a hybrid supercapacitor based on an activated corn stigma-derived carbon (PCC) electrode combined with a large-capacity faradic 1D nano-fiber/2D nanosheet Ni(OH)2 electrode is designed to fulfill this goal. Benefiting from the highly conductive, porous construction, and 3D open framework of PCC electrode couple with unique hierarchical 1D nanofiber/2D nanosheet Ni(OH)2, such 1D/2D Ni(OH)2/PCC electrode is capable of increasing accessible active sites, short-ening ion-diffusion path, and accelerating mass transfer. More importantly, DFT calculations unveil that 1D/2D Ni(OH)2/PCC composites own high electrical conductivity and OH- adsorption energy. Therefore, the specific capacity of the 1D/2D Ni(OH)2/PCC composite electrode reaches 655.9C g-1 at the current density of 1 A/g. Moreover, such hybrid 1D/2D Ni(OH)2/PCC||PCC supercapacitor show an outstanding energy density and power density of 38.6 Wh kg-1, and 1.03 kW kg-1, respectively. This work provides the possibility of fabricating hi-erarchical hydroxide/bio-carbon as a better electrode for high-energy-density electrochemical supercapacitors.