Recently, the research team of the Institute of Electrical Engineering of the Chinese Academy of Sciences Ma Yanwei has made progress in the quantitative preparation of graphene and high-performance graphene-based supercapacitors. He proposed using carbon dioxide as a raw material and adopting self-propagating high-temperature synthesis to successfully achieve both high conductivity and high conductivity. The specific surface area of ​​graphene powder is fast, green, and low cost. The relevant research results have been published in the international journal Advanced Materials (2017, 1604690) and applied for national invention patents and PCT patents.
Graphene is a new type of material that has received great attention from various countries in recent years, but the large-scale industrialization of high-quality graphene has always been a worldwide problem. At present, the technical route for large-scale preparation of graphene powders is mainly based on the exfoliated graphite exfoliation method and graphite oxide reduction method, but the former generally obtains a multi-graphite sheet with a low specific surface area, and the latter produces graphene due to residual oxygen functionalities. The group and structural defects lead to low conductivity, which severely restricts the potential application of graphene.
In response to the above problems, the team successfully used carbon dioxide as a raw material, metal magnesium powder as a reducing agent, and nano magnesium oxide as a template agent to successfully prepare graphenes rich in mesoporous structure through self-propagating combustion of magnesium powder in a carbon dioxide atmosphere. Figure 1 shows. At present, the graphene has a high conductivity of 13,000 S/m and a specific surface area of ​​709 m2/g. It has excellent overall performance and exhibits superior electrochemical performance in ionic liquid electrolytes. The electrode-based material has a specific capacitance of 244 F/g, an energy density of 136 Wh/kg, a power density of up to 1000 kW/kg, and a capacity retention rate of more than 90% after 1 million cycles, as shown in Fig. 2. The reaction process of the graphene preparation method is time-consuming, environment-friendly, low-cost, and easy to industrialize and promote, and will effectively promote the practical application of graphene in the energy storage field of super capacitors.
The study was carried out in collaboration with Li Jiangtao's research team of the Institute of Physics and Chemistry of the Chinese Academy of Sciences and Li Jianqi's research team of the Institute of Physics of the Chinese Academy of Sciences. It was also funded by the National Natural Science Foundation of China.
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