Abstract:
Double helical DNA structure is one of the most beautiful and fascinating nanoarchitecture nature has produced. Mimicking nature's design by the tailored synthesis of semiconductor nanomaterials such as WO sub(3) into a DNA-like double helical superstructure could impart special properties, such as enhanced stability, electrical conductivity, information storage, signal processing, and catalysis, owing to the synergistic interaction across helices. However, double helical WO sub(3) synthesis is extremely challenging and has never been reported earlier. This investigation presents the first-ever report on a facile synthesis route for designing a DNA-like double helical WO sub(3-x)/C microfiber superstructure via self-assembly of in situ carbon fiber-encapsulated WO sub(3-x) nanorods. This innovative design strategy is completely template-free and does not require predesigned helical templates or hydro/solvothermal treatment. Detailed spectroscopic material characterization and electrochemical studies confirmed that the double helical structure with carbon fiber-WO sub(3-x) heterostructures enabled effective induction and distribution of oxygen vacancies along with W sup(5+)/W sup(6+) redox surface states. Furthermore, faster electrode-electrolyte interfacial kinetics, improved electrical conductivity, and cycling stability has been observed in the carbon fiber-WO sub(3-x) heterostructures which resulted in a high area specific capacitance of 401 mF cm sup(-2) at 2 mA cm sup(-2) with excellent capacitance retention of greater than 94 percent for more than 5000 cycles. Additionally, the carbon fiber-WO sub(3-x) heterostructures demonstrated promising performance when fabricated in a solid-state asymmetric supercapacitor device with the power density of 498 W kg sup(-1) at an energy density of 15.4 W h kg sup(-1). Therefore, the rare DNA-like double helical WO sub(3-x)/C superstructure synthesized in this study could open new doorways toward in situ, facile fabrication of double helical superstructures for energy and environmental applications.
