The colorful leaves are tapped by the science "magic wand" and turn into a positive capacitor. The reporter learned from Nankai University on the 5th that Professor Zhou Zhen of the School of Materials Science and Engineering of the school used the ordinary leaves from the campus as raw materials to prepare highly efficient cathode materials, which greatly improved the overall performance of the sodium ion capacitor. This achievement was published in the latest issue of Advanced Functional Materials and was also funded by the National Key R&D Program.
According to reports, due to taking into account the high energy density of the battery and the high power density of the supercapacitor, the sodium ion capacitor has attracted much attention as a new type of energy storage device. However, the energy storage capacity of the existing sodium ion capacitor cathode material is far less than that of the negative electrode. To make both have the same storage capacity, it is necessary to make a large, heavy positive electrode, which greatly limits the sodium ion capacitor in the Wide application of energy storage. Zhou Zhen said that the existing sodium ion capacitors mostly use commercial activated carbon as a positive electrode. Their team is unique in its approach. Using pear leaves as raw materials, it has successfully prepared biomass carbon materials with high specific surface area as adsorption positive electrodes. Compared with commercial activated carbon, this biomass carbon material prepared from leaves exhibited rapid absorption and desorption characteristics of anions and outstanding cycle stability, which greatly increased the storage capacity and charging and discharging speed of the capacitors.
In addition, the research group also introduced carbon nanotubes through electrospinning technology, and designed and prepared nanorods in which titanium dioxide and carbon nanotubes are uniformly dispersed in carbon materials as an embedded negative electrode. The research team assembled the sodium ion capacitors by rational matching of the above two materials. The device exhibits high energy density, excellent power density, and long cycle stability. It effectively solves the problems such as the mismatch of the positive and negative electrode electrochemical reaction kinetics existing in existing capacitors, and successfully drives the mini fan experiment. It is further proved that the sodium ion capacitor has a high voltage output. This achievement provides a new idea for the subsequent research and development of sodium ion capacitors, and also provides the possibility for further practical application. (Reporter Sun Yusong)
