Hybrid electrochemical capacitors (HECs), which combine a battery-type negative electrode with a capacitive positive electrode, have recently attracted huge scientific and industrial interest since they can provide high energy densities at high power.
The architecture and design of hybrid supercapacitors showed that suitable composition of materials used can yield good performance of the supercapacitors. As a high-performing energy storage device, hybrid supercapacitors have been applied in various sectors with automotive and consumer electronic products taking the bigger share.
The integrating systems comprising of batteries and supercapacitors termed as hybrid devices with one shadowing the limitation of the other. Battery electrode contributes to the energy storage advantage while the supercapacitor electrode contributes to the power density advantage.
Design and fabrication of Zn ion hybrid capacitors devices. With the increasing demands for high-performance energy storage devices, aqueous zinc-ion hybrid capacitors (ZICs) attract lots of attention due to the integration of high-energy-density zinc-ion batteries (ZIBs) and high-power-density supercapacitors (SCs).
3. The development of capacitor-type electrode materials for Zn-based hybrid capacitors Normally, EDLC and pseudocapacitive materials are regarded as capacitor-type electrodes of ZICs, such as activated carbon (AC), porous carbon (PC), nanostructured carbon, MXenes, transition metal oxides and conducting polymers.
Compared to symmetric capacitors, hybrid capacitors have a large potential window and a high specific capacitance . In general, hybrid capacitors employ three types of electrodes: composite electrodes, battery-type electrodes, and asymmetric electrodes. The types of hybrid electrodes are summarized in Fig. 7.