RESUMEN
With the contemplations of ecological and environmental issues related to energy harvesting, piezoelectric nanogenerators (PNGs) may be an accessible, sustainable, and abundant elective wellspring of energy in the future. The PNGs' power output, however, is dependent on the mechanical energy input, which will be intermittent if the mechanical energy is not continuous. This is a fatal flaw for electronics that need continuous power. Here, a self-charging flexible supercapacitor (PSCFS) is successfully realized that can harvest sporadic mechanical energy, convert it to electrical energy, and simultaneously store power. Initially, chemically processed multimetallic oxide, namely, copper cobalt nickel oxide (CuCoNiO4) is amalgamated within the poly(vinylidene fluoride) (PVDF) framework in different wt % to realize high-performance PNGs. The combination of CuCoNiO4 as filler creates a notable electroactive phase inside the PVDF matrix, and the composite realized by combining 1 wt % CuCoNiO4 with PVDF, coined as PNCU 1, exhibits the highest electroactive phase (>86%). Under periodic hammering (â¼100 kPa), PNGs fabricated with this optimized composite film deliver an instantaneous voltage of â¼67.9 V and a current of â¼4.15 µA. Furthermore, PNG 1 is ingeniously integrated into a supercapacitor to construct PSCFS, using PNCU 1 as a separator and CuCoNiO4 nanowires on carbon cloth (CC) as the positive and negative electrodes. The self-charging behavior of the rectifier-free storage device was established under bending deformation. The PSCFS device exhibits â¼845 mV from its initial open-circuit potential â¼35 mV in â¼220 s under periodic bending of 180° at a frequency of 1 Hz. The PSCFS can power up various portable electronic appliances such as calculators, watches, and LEDs. This work offers a high-performance, self-powered device that can be used to replace bulky batteries in everyday electronic devices by harnessing mechanical energy, converting mechanical energy from its environment into electrical energy.
RESUMEN
Enhanced electrochemical performance of supercapacitors can be achieved through optimal hybridization of electroactive nanomaterials, as it effectively increases the overall surface area and ensures greater electrolyte-electrode interaction. This work reports the realization of a manganese tungstate and amorphous carbon nanotube (MnWO4-aCNT) hybrid and its utilization as the electrodes for a solid-state asymmetric supercapacitor. Large-scale synthesis of aCNTs was carried out via an economical solid-state reaction at low temperature and the walls of these nanotubes were decorated with MnWO4 nanorods via a surfactant-free in situ hydrothermal process. The as-fabricated electrode based on this hybrid over nickel foam delivered a high specific capacitance of 542.18 F g-1 at a scan rate of 2 mV s-1, which is much superior to the values of the structural units separately. This MnWO4-aCNT based electrode showed a high-rate capacity with â¼100% capacitance retention and a coulombic efficiency of â¼100% even after operation for 15 000 cycles. A solid-state asymmetric supercapacitor based on this hybrid attained an energy density of 5.6 W h kg-1 and a power density as high as 893.6 W kg-1. Significantly enhanced electrochemical behaviour registered from the hybrid sample is accounted for by its enhanced surface area and thereby greater number of redox reaction sites along with the positive synergetic effect of the building blocks. This study unlocks further exploration possibilities with other types of aCNT-based hybrid materials for the development of highly stable, non-toxic and cost-effective sustainable energy storage systems.
RESUMEN
Numerous reports have been made in the literature on the usability of a halide perovskite, namely methyl ammonium lead iodide (CH3NH3PbI3), as a light harvesting material. Suitable optimization in material composition and synthesis has led to an improvement in device performance. However, the susceptibility of CH3NH3PbI3 towards atmospheric water is an alarming issue which hinders its long-term application in day-to-day life. Herein, low temperature synthesized V2O5 nanorods are incorporated into the CH3NH3PbI3 matrix to facilitate carrier dynamics by interface engineering. The optimized hybrid sample exhibits a much improved and stable photo-response behaviour than the pristine building blocks. Additionally, the modified perovskite shows improved hydrophobicity in the form of small-scale surface undulations due to the incorporation of V2O5 nanorods into it. This way, we have solved two problems with one single action, firstly by improving the device performance and secondly by stabilizing the sample against ambient water species.
RESUMEN
Amorphous carbon nanotubes (a-CNTs) have been synthesized by a simple low-temperature process and have been grafted with chemically synthesized nickel oxide microflowers with different concentrations. The phase and morphology of the as-prepared pure and hybrid samples were characterized by X-ray diffraction and field emission scanning and transmission electron microscopes. Thermal properties of the samples were estimated by using thermal gravimetric and differential thermal analysis. The optical properties of the sample were characterized by UV-vis spectroscopic, Raman spectroscopic, and Fourier-transformed infrared spectroscopic analysis. The electrochemical performance of all hybrid samples has been done in detail for different scan rates as well as from charge-discharge analysis. It has been seen that because of the nickel oxide grafting, the electrochemical performance of pure a-CNTs gets enhanced significantly. The value of the specific capacitance of the hybrid comes out to be around 120 F/g for the best sample, which is almost 12 times higher compared to that of the pure a-CNTs. The result has been explained in terms of change in effective surface area as well as change in conductivity of the hybrid samples.
