Scientists have discovered new raw materials for direct carbon fuel cells

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www.most.gov.cn April 17, 2009 In the UK alone, over 100,000 tons of medium-density fiberboard (MDF) are discarded by the furniture industry each year; however, this discarded fiberboard now finds new uses. According to a recent report in the journal New Scientist, waste fiberboard can be converted into electrical energy without burning. This micro-energy generation technology can help factories reduce their reliance on electricity sourced from external sources, and it also makes the emissions generated during the production process easier to store. 　　 With the rapid growth of the building materials industry over the past 30 years, tens of thousands of medium-density fiberboard panels have flooded the market. This type of fiberboard is inexpensive, flexible, and does not break like wood, which makes it one of the highly popular materials in the furniture manufacturing industry. 　　 John Owen from the University of St Andrews in the UK and his team say that medium-density fiberboard can supply electricity to direct carbon fuel cells (DCFCs) with minimal modification. Direct carbon fuel cells are a type of efficient and clean fuel cell technology; their principle is that carbon and oxygen can generate electrical energy through electrochemical reactions without the need for vaporization or reforming, achieving an efficiency of up to 80%, with a fuel utilization rate of around 100%. 　　 Since direct carbon fuel cells do not waste excess heat, their efficiency can reach twice that of internal combustion engines. To date, various direct carbon fuel cells using molten carbonates, molten hydroxides, and solid oxides as electrolytes have been developed. Although direct carbon fuel cells also release carbon dioxide, the gas is emitted in a clean manner, without being mixed with nitrogen and other pollutants as in the case of emissions from burning carbon-containing fuels. This **reduces the difficulty of carbon capture and prevents air pollution caused by exhaust gases, which is of great significance for pollutant control and energy conservation. 　　 Owen and his research team first treated the medium-density fiberboard chips in a high-temperature nitrogen environment at 500°C to remove water vapor and other volatile gases. Owen said that this cost-effective process makes medium-density fiberboard more compact, lighter, and easier to transport to the desired locations. Subsequently, the researchers dried the treated fiberboard to produce a powder, which was mixed with lithium and potassium carbonate to serve as an electrolyte for fuel cells. At temperatures between 500°C and 800°C, these mixtures facilitate the combination of carbon in medium-density fiberboard with oxygen injected into the battery, producing carbon dioxide and ionizing electrons to generate the desired current. 　　 The resulting battery can deliver 100 milliwatts of power per square centimeter at a current density of 200 milliamps per square centimeter, which means that a square battery with sides of 10 centimeters can generate a voltage of 2 volts at a current of 20 amperes. This is similar to other types of direct carbon fuel cells and can be applied in large-scale power plants. 　　 Although Kars Hemmers from Delft University of Technology in the Netherlands agrees with this research, in the future the main role of direct carbon fuel cells may be to produce hydrogen through the chemical decomposition of natural gas, and to utilize the remaining carbon after supplying energy to other types of fuel cells. However, small-scale energy generation using waste materials such as medium-density fiberboard still has room for development in the market. 　　 At the same time, Cas Hemos also hopes to see more data on medium-density fiberboard. He believes that the research team has only shown that there is an extremely large amount of fiberboard available; researchers still need to quantify the actual figures further in order to support the implementation of this study. 　　 (Science and Technology Daily)