Schematic illustration of TiC/CNTs@Ti free-standing cathodes used in zinc ion capacitor with high capacity and long-term stability.
The development of aqueous zinc-ion capacitors (ZICs) is an effective approach to improve the safety and environmental friendliness of energy storage devices. In this paper, TiC/CNTs core-shell array structures (TCT) were synthesized on titanium substrate through in-situ simple chemical vapor deposition and carbon reduction and used as self-supporting cathodes for aqueous ZICs. As expected, as-prepared TCT electrode exhibited excellent electrochemical performance in aqueous electrolytes, demonstrating a high specific capacitance of 275.13 F g−1 at a current density of 1.0 A g−1 and maintaining 90.5 % of its initial capacity after 10000 charge-discharge cycles. The assembled Zn//TCT ZIC displays excellent rate capability, delivering an excellent specific capacitance of 298.2 F g−1 at 0.5 A g−1 and 193.5 F g−1 at a high current density of 10 A g−1. Zn//TCT device can provide an ultra-high energy density of 24.8 Wh kg−1 at a power of 6984.1 W kg−1. DFT calculations further demonstrate that a large number of electrons are transferred at the TiC/CNT interface and stable TIC−C bonds can be formed. This work provides a new strategy for rationally designing transition metal carbide electrodes and constructing ZICs with high energy and power densities.Zum Volltext