Ultrathin supercapacitor electrodes with high volumetric capacitance and stability using direct covalent-bonding between pseudocapacitive nanoparticles and conducting materials

Hybrid supercapacitor electrodes for electrochemical energy storage devices were prepared from covalent-bonding LbL-assembled (CNT/OA-Fe3O4 or OA-MnO NP)n multilayers. The resulting (CNT/OA-Fe3O4 NP)n and (CNT/OA-MnO NP)n electrodes exhibited the high volumetric capacitances of 248±15 F cm−3 (128±7 F g−1) and 305±10 F cm−3 (183±5 F g−1) at 5 mV s−1, respectively and the excellent operation stability due to a facile electrolyte access, a dense adsorption of pseudocapacitive TMO NPs, and high surface area for fast electrochemical reactions.418