Mesoporous hollow carbon spheres boosted, integrated high performance aqueous Zn-Ion energy storage

Since low cost, environment-friendly, safe, superior rate capability and long cycling life, rechargeable Zn-ion hybrid supercapacitors have received increasing attention for aqueous energy storage systems. However, the application of Zn-ion hybrid supercapacitors is seriously challenging. The dendritic growth of Zn on the anodes always leads to capacity attenuation or even short-circuit device and the absence of excellent cathode materials constrain further development. Herein, a novel rechargeable aqueous Zn-ion hybrid supercapacitors with mesoporous hollow carbon spheres as the cathode and mesoporous hollow carbon spheres coating Zn foil as the anode is reported. The excellent nanostructure of mesoporous hollow carbon spheres not only provide better double layer performance but also depress and regulate the growth of dendrites/protrusions for Zn anodes. The new Zn-ion hybrid supercapacitor exhibits a high power density of 13.7 kW kg-1 at 36.8 Wh kg-1 and a high energy density of 129.3 Wh kg-1 at 266.4 W kg-1, excellent cycle stability of 100% after 1000 cycles at 0.1 A g−1 and 96% after 10000 cycles at 1 A g−1. More importantly, with a high mass loading of 20 mg cm−2, Zn-ion hybrid supercapacitors also achieve high gravimetric capacitances and ultrahigh areal capacitance.