Kinetic Well-matched Full-carbon Sodium-ion Capacitor
Sodium-ion capacitors (SICs), as the new-generation electrochemical energy-storage systems, have combined the advantages of high energy/power densities, meeting a urgent demand for versatile electronic equipments and grid energy-storage stations. Nevertheless, the electrochemical performance of SICs is seriously restricted by the kinetic mismatching of battery-type anode versus capacitor-type cathode. In this work, 3D carbon (NHPC) with N-doping delivers a high reversible specific capacity of 197 mAh g-1 at 2 A g-1, which is dominated by strong pseudocapacitive storage mechanism, serving as a prominent role for harmonizing the quick physical adsorption/desorption process. Moreover, through further activation of NHPC, the nitrogen-doped hierarchical porous activated carbon (NHPAC) displays a large specific surface area of 1478 m2 g-1 with abundant meso/macropores, bringing about the fast adsorption/desorption of the anion on the surface. Fundamentally, benefiting from the similar material system of anode/cathode, the full-carbon SIC device achieves a great energy density of 115 Wh kg-1 at 200 W kg-1 as well as marvelous long-term cyclability in the potential range of 0-4.0 V. This rational strategy of kinetic matching might open up a potential avenue for the advanced SICs.
- This article is part of the themed collection: 2019 Journal of Materials Chemistry A HOT Papers