rGO‐Wrapped Hexagonal WO3Nanorod as Advanced Electrode Material for Asymmetric Electrochemical Supercapacitors

The multiple oxidation states of redox‐active materials enable them to store high‐energy better than the commonly used carbon‐based electrode materials. Accounting for these advantages, designing asymmetric supercapacitors by coupling redox‐active materials as positive electrodes with carbon‐based negative electrodes becomes a very attractive strategy. Herein, reduced graphene oxide‐wrapped hexagonal WO3nanorod (rGO‐WO3NR) by simple hydrothermal synthesis method is synthesized. Because of improved reaction kinetics resulting from the close contact between rGO and WO3NRs, rGO‐WO3NR demonstrates superior electrochemical properties than pure WO3. Motivated by the very high areal capacitance (2.5 F cm−3at the applied current of 30 mA cm−2), an asymmetric SC device by combining rGO‐WO3NR with activated carbon is assembled. The as‐assembled rGO‐WO3NR//activated carbon asymmetric supercapacitor device demonstrates outstanding electrochemical performance in an operating voltage window of 1.2 V, admirable cycling stability of ≈95% (even after 14 000 cycles), with an energy density of 24.1 Wh Kg−1at a power density of 1532.6 W Kg−1. These demonstrate the combination of redox‐active materials with high energy density can importantly boost the energy storage capacity of a supercapacitor. rGO‐wrapped hexagonal WO3nanorod (rGO‐WO3NR) is synthesized by a simple hydrothermal method. The rGO‐WO3NR//activated carbon asymmetric supercapacitor device demonstrates outstanding electrochemical performance: admirable cycling stability of ≈95% (even after 14 000 cycles), with the energy density of 27.1 Wh kg−1at a power density of 1532.66 W kg−1.