3-D ordered bimodal porous carbon/nickel oxide hybrid electrodes for supercapacitors

• 3D-ordered bimodal porous carbons were fabricated as electrode materials.
• The electrodes were prepared with nickel oxide nanoparticles of 2–4 nm.
• EDLC and pseudocapacitive redox reaction were applied to the electrodes.
• The electrodes showed superior capacitance, rate capabilities, and cycle stability.

3D-ordered bimodal porous carbons (3D-OBPCs) were fabricated, containing well-ordered macropores and a large amount of sub-/nanometer pores (micropores) with narrow pore size distribution. Nickel oxide (NiO) nanoparticles of 2–4 nm were introduced on the 3D-OBPCs. The 3D-OBPC/NiO nanoparticle hybrid exhibited better electrochemical performance than that of 3D-ordered macroporous carbon/NiO nanoparticle hybrid, because of the synergistic effects from the electric double-layer capacitance of a large amount of micropores, enhanced wettability due to oxygen heteroatoms introduced from the activation process, and pseudocapacitive redox reactions of NiO nanoparticles.