A High-Performance Sodium-Ion Hybrid Capacitor Constructed by Metal-Organic Framework-Derived Anode and Cathode Materials

Sodium-ion hybrid capacitors (SIHCs) can potentially combine the virtues of high-energy density of batteries and high-power output as well as long cycle life of capacitors in one device. The key point of constructing a high-performance SIHC is to couple appropriate anode and cathode materials, which can well match in capacity and kinetics behavior simultaneously. In this work, a novel SIHC, coupling a titanium dioxide/carbon nanocomposite (TiO2/C) anode with a 3D nanoporous carbon cathode, which are both prepared from metal-organic frameworks (MOFs, MIL-125 (Ti) and ZIF-8, respectively), is designed and fabricated. The robust architecture and extrinsic pseudocapacitance of TiO2/C nanocomposite contribute to the excellent cyclic stability and rate capability in half-cell. Hierarchical 3D nanoporous carbon displays superior capacity and rate performance. Benefiting from the merits of structures and performances of anode and cathode materials, the as-built SIHC achieves a high energy density of 142.7 W h kg(-1) and a high power output of 25 kW kg(-1) within 1-4 V, as well as an outstanding life span of 10 000 cycles with over 90% of the capacity retention. The results make it competitive in high energy and power-required electricity storage applications.