Synthesis of ZIF-L-Derived Hollow Carbons for Zinc-Ion Capacitors

Hollow carbon nanomaterials have received great attention due to their unique morphology-dependent characters. Herein, a controlled thermal treatment approach was developed to prepare leaf-like hollow carbon materials with a porous shell and multiple faradaic reactive sites. Thanks to the hollow structure and rich dopants of the carbon materials, enhanced electrolyte adsorption/desorption and transport have been achieved when used as cathode materials for aqueous zinc-ion capacitors (ZICs), which are an emerging type of high-power energy storage devices owing to the high safety, low cost, and excellent electrochemical properties. Compared to solid carbon cathodes, the electrochemical performance is significantly boosted for hollow carbon cathodes. The optimum assembled ZICs delivered a high capacity of 144.2 mA h g–1, a high energy density of 94 W h kg–1, and good cycling performance up to 2500 cycles with 82.4% capacity retention at 2 A g–1.