Confinement effect of natural hollow fibers enhances flexible supercapacitor electrode performance

In Situ, Nitrogen-Doped Porous Carbon Derived from Mixed Biomass as Ultra-High-Performance Supercapacitor

How to address the destruction of the porous structure caused by elemental doping in biochar derived from biomass is still challenging. In this work, the in-situ nitrogen-doped porous carbons (ABPCs) were synthesized for supercapacitor electrode applications through pre-carbonization and activation processes using nitrogen-rich pigskin and broccoli. Detailed characterization of ABPCs revealed that the best simple ABPC-4 exhibited a super high specific surface area (3030.2-3147.0 m2 g-1) and plentiful nitrogen (1.35-2.38 wt%) and oxygen content (10.08-15.35 wt%), which provided more active sites and improved the conductivity and electrochemical activity of the material. Remarkably, ABPC-4 showed an outstanding specific capacitance of 473.03 F g-1 at 1 A g-1. After 10,000 cycles, its capacitance retention decreased by only 4.92% at a current density of 10 A g-1 in 6 M KOH. The assembled symmetric supercapacitor ABPC-4//ABPC-4 achieved a power density of 161.85 W kg-1 at the maximum energy density of 17.51 Wh kg-1 and maintained an energy density of 6.71 Wh kg-1 when the power density increased to 3221.13 W kg-1. This study provides a mixed doping approach to achieve multi-element doping, offering a promising way to apply supercapacitors using mixed biomass.

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.

Morphological Structure and Basic Characteristics of Miscanthus floridulus Fibers

Miscanthus floridulus fibers obtained from the seed floss of M. floridulus (a perinneal plant of Gramineae native to Africa and Asia and widely distributed in tropical and subtropical regions) have potential application value in textile and other fields. At present, the biological characteristics and ecological benefits of Miscanthus floridus have been extensively studied by researchers, but there have been no literature on M. floridus fibers. In order to make reasonable use of M. floridus fibers, their morphological structure, physical properties, chemical composition, thermal insulation properties, and surface absorption properties were explored in detail in this study. The results showed that the M. floridus fiber is fine and short and has a hollow structure with a density of 0.67 g cm^-3. Chemical analyses revealed that the main constituents of the fiber are cellulose (66.98%), hemicelluloses (13.86%), lignin (6.97%), pectin (1.99%), and wax (4.38%). The fill power and warmth retention performance of the fiber are similar to those of wool. In particular, the M. floridus fiber surface has hydrophobic and lipophilic properties with a static contact angle of 123.7° for water droplets in equilibrium. Therefore, the M. floridus fiber has a promising application prospect in bulk textile thermal insulation and oil-water separation fields.

Utilization of waste wool felt architecture to synthesize self-supporting electrode materials for efficient energy storage

Conversion of waste wool felt into electrode material for supercapacitor.

Classification of Spatially Confined Reactions and the Electrochemical Applications of Molybdenum-Based Nanocomposites

As a popular material synthesis method, spatially confined reactions have been gradually recognised for their excellent performance in the field of current materials synthesis. In recent years, molybdenum-based catalysts have gradually gained recognition due to high natural reserves of Mo, its low cost, and many other advantages, and they have wide applications in the area of functional materials, especially in topical areas such as batteries and electrocatalysts. In this context, spatially confined reactions have become widely to obtain various types of molybdenum-based electrode materials and electrocatalysts which result in an excellent morphology, structure, and performance. In this review, the concept of a spatially confined reaction system and the electrochemical application (electrode materials and electrocatalyst) of molybdenum-based materials synthesised in this way are comprehensively discussed. The current problems and future development and application of molybdenum-based materials are also discussed in this review.

In situ growth of luminescent perovskite fibers in natural hollow templates

Natural hollow fibers were used as templates to in situ produce thin Cs4PbX6 nanosheets on the inner walls, forming luminescent fibers that integrated the advantages of the large length of fibers and the emission tunability of perovskites, and exhibited great robustness as well for multiple applications like warning signs, anti-counterfeiting and fashion.

Toward fiber-, paper-, and foam-based flexible solid-state supercapacitors: electrode materials and device designs

Flexible solid-state supercapacitors possess promising safety performance and intrinsic fast charging-discharging properties, enabling them to accomplish the requirements of lightweight and multifunctional wearable electronics that have recently become fairly popular. Because electrode materials are the core component of flexible solid-state supercapacitors, we exhaustively review the recent investigations involving electrode materials that have used carbons, metal oxides, and conductive polymers. The principles and methods of optimizing and fabricating electrodes for use in flexible supercapacitors are discussed through a comprehensive analysis of the literature. In addition, we focused on three types of flexible solid-state supercapacitors (fiber-, paper-, and porous foam-based structures) to satisfy the requirements of flexible electronic devices. Further, we summarize the practical applications of flexible solid-state supercapacitors, including energy conversion/collection devices and energy storage/detection devices. Finally, we provide the developmental direction for flexible solid-state supercapacitors in the future.