Eco‐Friendly Synthesis of 3D Disordered Carbon Materials for High‐Performance Dual Carbon Na‐Ion Capacitors
Alba Fombona‐Pascual, Noel Díez, Antonio B. Fuertes, Marta Sevilla
Abstract
Abstract An eco‐friendly and sustainable salt‐templating approach was proposed for the production of anode materials with a 3D sponge‐like structure for sodium‐ion capacitors using gluconic acid as carbon precursor and sodium carbonate as water‐removable template. The optimized carbon material combined porous thin walls that provided short diffusional paths, a highly disordered microstructure with dilated interlayer spacing, and a large oxygen content, all of which facilitated Na ion transport and provided plenty of active sites for Na adsorption. This material provided a capacity of 314 mAh g −1 at 0.1 A g −1 and 130 mAh g −1 at 10 A g −1 . When combined with a 3D highly porous carbon cathode ( S BET ≈2300 m 2 g −1 ) synthesized from the same precursor, the Na‐ion capacitor showed high specific energy/power, that is 110 Wh kg −1 at low power and still 71 Wh kg −1 at approximately 26 kW kg −1 , and a good capacity retention of 70 % over 10000 cycles.