Supercapacitors are becoming a key, practical storage technology that can be used for energy-efficient transportation as well as for renewable energy sources such as grid buffers. These devices have the advantages of traditional capacitors, can quickly transfer high-density currents to meet the needs, but also has the advantages of batteries, can store a lot of power.
Characteristics of Manganese Dioxide-Carbon Nanotube-Sponge electrode: (a) Three-dimensional macroporous layered manganese dioxide-carbon nanotube-sponge electrode under perspective; (b) Manganese dioxide uniformly deposited on carbon nanotubes Sponge structure; (c) High-magnification of porous manganese dioxide nanoparticles on carbon nanotube sponges. The inset shows the morphology of single manganese dioxide flower-like particles.
Supercapacitors provide a low-cost alternative energy source that replaces rechargeable batteries for various devices such as power tools, mobile electronics, and electric vehicles. Some car manufacturers are exploring the concept of combining supercapacitors with lithium-ion batteries as the next generation of energy storage systems for hybrid cars. Although the energy density of a capacitor is much lower than that of a battery, its power density is much higher, which allows them to generate explosive power, which helps a new generation of cars to have the same or better speed when accelerating than traditional ones. Gasoline engine vehicles can significantly reduce fuel consumption.
Researchers have now made new high-performance sponge supercapacitors using a simple and scalable approach. Their research has been reported in the recently published Nano Letters, entitled "High-Performance Nanostructured Supercapacitors on a Sponge". The research team is based in Azerbaijan. King Abdullah University of Science and Technology (KAUST), in Saudi Arabia, is headed by Husam N. • Husam N. Alshareef, they showed that this three-dimensional electrode may have a huge advantage over traditional hybrid electrode materials.
"We show that the supercapacitor electrode is made using a macroporous structure that can increase the speed and specific capacitance of the supercapacitor," Alcheriev said. “We have been using sponges because they offer novel and exciting properties that are different from paper and fabrics: First, sponges have more uniform pore sizes. Second, cellulose or polyester fibers. ) Connect to each other, in fact no knots are required. This way, it is much easier to apply nanomaterials continuously because no knots need to pass through.)
This sponge-based supercapacitor, designed and manufactured by the research team of King Abdullah University of Technology, uses a simple and scalable method. Their manufacturing process consists of four simple steps: First, a commercially available sponge is cleaned with water and acetone; then, after drying, cut into small ribbons; these ribbons are coated with carbon nanotube ink; finally, the researchers use Electrolytic deposition deposits manganese dioxide nanoparticles onto a sponge coated with carbon nanotubes.
“Because of the mechanical flexibility of the carbon nanotubes and the strong van der Waals interaction between the macroporous sponge cellulose and the carbon nanotubes, the carbon nanotubes are easily coated onto the sponge skeleton, making this The insulating sponge is highly conductive and requires only a simple dipping and drying process,” explains Alcherev.
When studying carbon nanotube-coated sponges, the researchers found that it still maintained the stratified macroporous nature, in which the pores of intricate clusters remained open and could flow through the electrolyte. This carbon nanotubes form a thin layer that wraps around the sponge skeleton.
"When we tested mechanical toughness, we also folded, twisted, and repeatedly stretched the carbon nanotube sponge skeleton," Alcheriev said. "After all mechanical tests, the sponge will always return to its original shape without any permanent deformation."
The team also tested the electrochemical performance of their sponge supercapacitors. "This large-pore sponge, together with porous electrolytically deposited manganese dioxide (MnO2) nanoparticles, forms a dual porous electrode structure with good electrical conductivity that allows the electrolyte to fully enter the manganese dioxide, which greatly improves The performance of manganese dioxide-carbon nanotube-sponge supercapacitors," Alcheriev said. “We have found that our sponge supercapacitors have high unit capacitance, fast charge and discharge rates, good cycle stability, and good energy and power density, making it a promising electrode for the future. Energy storage system."
This may be an interesting aspect of small mobile electronic devices. The sponge made of supercapacitors proved to be far lighter than rigid metal or other flexible substrates, but with the same area: a sponge area of 2 square centimeters, a thickness of 1 millimeter, and weight Only about 10 milligrams.
