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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 WO3 nanorod (rGO‐WO3 NR) by simple hydrothermal synthesis method is synthesized. Because of improved reaction kinetics resulting from the close contact between rGO and WO3 NRs, rGO‐WO3 NR demonstrates superior electrochemical properties than pure WO3. Motivated by the very high areal capacitance (2.5 F cm−3 at the applied current of 30 mA cm−2), an asymmetric SC device by combining rGO‐WO3 NR with activated carbon is assembled. The as‐assembled rGO‐WO3 NR//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−1 at 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. [ABSTRACT FROM AUTHOR]

• A novel ionic liquid-based polymer electrolyte (IL/PE) was prepared. • The IL/PE with dual redox additives exhibited high ionic conductivity (∼23.8 × 10−4 S cm−1) and a wide potential window (∼5.9 V). • A flexible symmetrical interdigitated planner device is fabricated using IL/PE and flower-like WS 2. • The flexible device delivered energy density of 47.86 µWh cm−2 at a power density of 3509 µW cm−2. Introducing redox-active species to enhance redox-activity at electrode–electrolyte interfaces, and designing the rational architecture of flexible supercapacitors comprising high-performance active materials and electrolytes with a wide potential window would be a key strategy to boost energy and power density. Herein, for the first time, we prepared an ionic liquid-based polymer electrolyte (IL/PE) by entrapping ionic liquid N-methyl-N-butyl pyrrolidinium bis (trifluoromethane sulfonyl) imide (P 14 TFSI)) in a polymer electrolyte Poly (diallyl dimethylammonium bis (trifluoromethane sulfonyl) imide (PDADMATFSI)) and blended with dual redox-additives (potassium iodide, KI and diphenylamine, DPA). The IL/PE with dual redox additives, demonstrates spectacular flexibility, high ionic conductivity (∼23.8 × 10−4 S cm−1), and stability in a wide potential window (∼5.9 V). A symmetrical interdigitated planner device is fabricated using dual redox-active IL/PE and flower-like WS 2 electrode material. Benefiting from the synergistic effect of dual redox-active additive, the highest energy density of 47.86 µWh cm−2 at a power density of 3509 µW cm−2, and a high working potential (3 V) with excellent cycling stability upto 20,000 cycles has been achieved. [ABSTRACT FROM AUTHOR]

As an attractive family of anode material for lithium‐ion battery (LIB), transition metal dichalcogenides (TMDs) with high energy density has been emerging very fast. Among various TMDs, tungsten disulphide (WS2) with its intrinsically layered structure is a promising alternative anode candidate because of its high theoretical capacity. However, WS2 usually suffers from poor cycling stability due to its large volume change during lithiation and delithiation process. Herein, we have synthesized carbon free nanostructured plate like WS2 (NP‐WS2) by an easy one pot hydrothermal synthesis process. Without introducing any conducting carbonaceous materials, the P‐WS2 showing extraordinary lithium storage properties. At a C‐rate of C/8, the observed initial lithiation and delithiation capacities are 682.0 and 555.7 mAh g−1, respectively. During the cycling stability test at a rate of C/4, even after 200 cycles P‐ WS2 delivered high delithiation capacity of 380 mAh g−1. Even without incorporation of conducting carbonaceous materials, NP‐WS2 demonstrated extraordinary lithium storage performance which indicates its potential as an alternative high capacity anode material for lithium‐ion battery. [ABSTRACT FROM AUTHOR]