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The development of the battery‐type electrode for the hybrid supercapacitor is very challenging owing to poor cycle stability. To overcome this problem, heterostructures would be an excellent alternative attributed to the synergetic effect of different materials physical properties, including electrical conductivity, mechanical flexibility, and so forth. Furthermore, heterostructures also offer significant redox reactions on account of more active sites, enhanced charge transfers kinetics via extra electron carriers, and ion diffusion rates, along with improved cyclic stability. Herein, we prepared heterostructures of Co3O4 nanospheres and WO3−x nanorods via a single‐step wet chemical method at a reaction time of 1 h (CoW1) and 6 h (CoW2). The electrochemical investigations reveal improved specific capacitance of CoW1 (157 F g−1) than CoW2 (188 F g−1) at 0.3 A g−1. Furthermore, an aqueous hybrid supercapacitor (AHS) shows the specific capacitance of 38 F g−1 at 1 A g−1. Notably, it exhibits a remarkable specific capacity retention of 93% up to 10 000 cycles at 100 mV s−1. Thus, CoW2 have great potential of electrode materials for the next‐generation energy storage devices. [ABSTRACT FROM AUTHOR]

Owing to the remarkable adjustability of layers, layered double hydroxides (LDHs) can adopt superior conductivity and a charge-storage capacity. However, controlled tuning of layers spacing in LDHs is a major challenge, and they can suffer from stacking issues, structural degradation, and issues with interstitial ion insertion. Herein an effective strategy of exchanging interlayer ions within laminates was efficiently realized. Despite the layered spatial structure and morphological perturbation, the exchange of carbonate ions (CO32−) by sulfate anions (SO42−) into the interlayers of the NiFe-LDHs nanostructure revealed an expansion of the layer spacing and rapid ion intercalation. A three-fold enhancement of the specific capacitance in NiFe-LDHs with sulfate anions (NFS), i.e. 527 F g−1, was achieved over NiFe-LDHs with carbonate anions (NFC), i.e., 171 F g−1, at 0.5 A g−1 in 6 M KOH aqueous electrolyte. Further, the aqueous hybrid supercapacitor (AQHS) of NFS-LDHs nanoplates displayed a high specific capacitance of 30 F g−1 at 0.5 A g−1, with a high energy density of 11 W h kg−1 and a power density of 5500 W kg−1. It eventually exhibited a tremendous capacitance retention of 83% at 3 A g−1 with a coulombic efficiency of 82% at up to 10 000 cycles. Thus the expansion of the layer spacing resulted in enhanced ionic intercalation, and improved conductivity and redox activity, underscoring the potential of NFS-based LDHs for advancing the performance of aqueous hybrid supercapacitors. [ABSTRACT FROM AUTHOR]

Electrode materials engineering at the nanoscale is essential to improve the electrochemical performance for next‐generation energy storage devices. Herein, a novel approach of sodium substitution in the tungsten oxide matrix is highligting the enhancement of the pseudocapacitor performance of the electrode in an aqueous asymmetric supercapacitor. The sodium‐substituted tungsten trioxide (NWO) and pristine tungsten oxide (PWO) nanoflowers prepared by a single‐step hydrothermal process has presented. The tetragonal crystal structure and nanoflower morphology has maintained even after Na substitution. The electrochemical properties of PWO and NWO have investigated with three‐electrode setups in 1 M H2SO4 aqueous electrolyte. The specific capacitance of PWO and NWO exhibits 104 F g−1 and 476 F g−1 at 1 A g−1, respectively. Furthermore, an aqueous asymmetric supercapacitor (AAS) of NWO demonstrates a specific capacitance of 41 F g−1, an energy density of 13 W h kg−1, and a power density of 3750 W kg−1. An excellent stability of AAS has achieved with 100 % capacitance retention from 1000 to 5000 cycles. The sodium substitution significantly enhanced the pseudocapacitive behavior, attributed to enhanced electroactive sites, conductivity, surface area, and chemical stability. It shows the potential of NWO nanoflowers as a promising candidate for next‐generation supercapacitor devices. [ABSTRACT FROM AUTHOR]