Three-dimensional kenaf stem-derived macroporous carbon/reduced graphene oxide/polyaniline integrated electrode for supercapacitors

Nanostructured Conducting Polymers and Their Applications in Energy Storage Devices

Due to the energy requirements for various human activities, and the need for a substantial change in the energy matrix, it is important to research and design new materials that allow the availability of appropriate technologies. In this sense, together with proposals that advocate a reduction in the conversion, storage, and feeding of clean energies, such as fuel cells and electrochemical capacitors energy consumption, there is an approach that is based on the development of better applications for and batteries. An alternative to commonly used inorganic materials is conducting polymers (CP). Strategies based on the formation of composite materials and nanostructures allow outstanding performances in electrochemical energy storage devices such as those mentioned. Particularly, the nanostructuring of CP stands out because, in the last two decades, there has been an important evolution in the design of various types of nanostructures, with a strong focus on their synergistic combination with other types of materials. This bibliographic compilation reviews state of the art in this area, with a special focus on how nanostructured CP would contribute to the search for new materials for the development of energy storage devices, based mainly on the morphology they present and on their versatility to be combined with other materials, which allows notable improvements in aspects such as reduction in ionic diffusion trajectories and electronic transport, optimization of spaces for ion penetration, a greater number of electrochemically active sites and better stability in charge/discharge cycles.

Smart-Fabric-Based Supercapacitor with Long-Term Durability and Waterproof Properties toward Wearable Applications

The rapid development of wearable electronics and smart textiles has dramatically motivated the generation of flexible textile-based supercapacitors (SCs). However, the rapid evaporation of water moisture in gel electrolyte substantially limits the working durability and performance enhancements of the flexible devices. Therefore, a high-performance multifunctional textile-based SC with long-term durability is highly desired. Herein, a poly(vinyl alcohol) (PVA)/polyacrylamide (PAM) composite gel electrolyte was developed to fabricate multifunctional device with water-retaining and water-proofing properties based on multidimensional hierarchical fabric. And the assembled SC based on composite gel exhibited a superior water-retaining property and long-term working durability (93.29% retention rate after operation for 15 days), whereas the performance of SC based on pure PVA gel declined sharply and only 43.2% capacitance remained. In addition, the assembled SC exhibited enhanced specific capacitance of 707.9 mF/cm² and high energy density of 62.92 μWh/cm² and maintained a good stability of 80.8% even after 10 000 cyclic tests. After water repellency treatment, the integrated device immersed in water could still work normally. What's more, the assembled devices could be charged by a portable hand generator, which could be potentially applied for field rescue and military applications. We foresee that this strategy would be a potential route to prepare high-performance multifunctional textile-based SCs for wearable electronic systems and smart textile applications.

Novel three-dimensional polyaniline nanothorns vertically grown on buckypaper as high-performance supercapacitor electrode

Combining polyaniline (PANI) with different dimensional carbon materials is an effective way to solve the disadvantages of poor rate performance and cycling stability induced by the structure destruction of conductive polymer materials over long-term charge/discharge cycles. In this work, novel three-dimensional (3D) conical PANI nanothorns are synthesized on a buckypaper substrate via a controlled electropolymerization process. Benefiting from the synergistic effect of the vertical growth of PANI nanothorns and the excellent mechanical elasticity of multi-wall carbon nanotubes, it can effectively alleviate the volume change during the charging and discharging process of the electrode material and ensure the rapid transmission of electrons. The morphology and structure of the composite have been characterized by scanning electron microscopy, x-ray diffraction, and Fourier transform infrared spectroscopy. The results show that the electrode exhibits a high specific capacitance of 742 F g^-1 at 1 A g^-1 in 1 M of H₂SO₄ electrolyte and a capacitance retention of 76% after 2000 cycles. The novel 3D PANI nanothorn/buckypaper composite has significant potential as practical for use as electrode materials of supercapacitors due to its easy synthesis, low cost, and high specific capacitance.