Chinese scientists recently discovered a new method in the conversion of organic waste matter into a porous carbon material, used to produce high-tech electronics.
Organic waste, or green waste is biodegradable and comes from either a plant or animal. Organic waste usually battered by other organisms over time and referred to as wet waste. Most of the time, it’s made up of vegetable and fruit debris, paper, bones and human waste which quickly disintegrate.
In China, phoenix trees produce an abundance of fallen leaves in autumn. Phoenix tree leaves generally burned in the colder season, make the country’s air pollution problem.
Researchers used a multi-step process to convert tree leaves into a form that incorporate into electrodes as active materials. The dried leaves produced a powder composed of small carbon microspheres. The microspheres treated with a solution of potassium hydroxide and heated at temperatures between 4500 to 8000 C.
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The chemical treatment damages the surface of the carbon microspheres at high temperatures. The product, black carbon powder, has high surface area due to the presence of many tiny pores that chemically etched on the surface of the microspheres. The high surface area gives the final product its extraordinary electrical properties.
Researchers charge a series of standard electrochemical tests on the porous microspheres to measure their potential for use in electronic devices. The current-voltage curves indicate that the substance could make an excellent capacitor.
The extended research show that the materials are supercapacitors, with a capacitance of 367 Farads/gram, which are three times higher than the values seen in some graphene supercapacitors.
Graphene supercapacitor is a widely used electrical component that stores, energy by holding a charge on two conductors, separate each other by an insulator. However, supercapacitor stores 10-100 times as much energy as an ordinary capacitor, also deliver charges much faster than a typical rechargeable battery.
For these reasons, the supercapacitive materials hold great promise for a wide variety of energy storage needs, particularly in computer technology and hybrid or electric vehicles.
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The research is mainly looking for ways to convert waste biomass into porous carbon materials for energy storage technology. In addition to tree leaves, researchers successfully converted potato waste, corn straw, pine wood, rice straw and other agricultural wastes into carbon electrode materials.
Also, the researchers plan to improve the electrochemical properties of porous carbon materials by optimizing the preparation process and allowing for doping or modification of the raw materials.
The properties of the porous carbon microspheres made from phoenix tree leaves, which are higher than other carbon powders obtained from other bio-waste materials. The porous structure eases contact between electrolyte ions and the surface of the carbon spheres, also enhancing ion transfer and diffusion on the carbon surface.
More information: [AIP]