Controllable assembly of hybrid electrodes by electrophoretic deposition for high-performance battery-supercapacitor hybrid devices

Hybrid electrodes, which are made of a physical (electrical double layer) storage component and a chemical (battery-type) material has shown great potential in battery-supercapacitor hybrid (BSH) devices. Here, we present an approach, which is based on electrophoretic deposition (EPD) as a means of assembling a binder-free, high-performance BSH device. Ketjenblack (KB) used as the physical storage material while NiCo2O4 (NCO) as the chemical storage compound were dispersed in the presence of Ni2+. The latter assisted to positively charge the surface of both materials and thus resulted in similar deposition rate by EPD on nickel foam (NF). This enabled to nicely control the NCO to KB ratio in the hybrid electrode and optimize its performance. In this binder-free hybrid electrode, the KB chains served as fast electron path providing high conductivity for the NCO electroactive material. More importantly, the KB chains could remain in contact with NCO coping with the mechanical stress during the electrochemic...