Energy & Environmental Science: new progress in the research of safety high power super capacitor of Lanzhou Institute of Chemical Technology

As an important energy storage device, super capacitor is limited in its application because of its low energy density The effective strategy to improve the energy density of supercapacitor is to use organic electrolyte with wide voltage window However, conventional organic electrolytes have high cost, low conductivity and potential safety hazards Comparatively speaking, water electrolyte has the characteristics of safety, low cost and easy operation However, the narrow voltage window of water electrolyte results in low energy density of water super capacitor Recently, researchers have developed a kind of high concentration "water in salt" aqueous electrolyte with large stable voltage window However, this kind of electrolyte has some problems such as high viscosity, low conductivity and not suitable for low temperature, which greatly limits the performance of the supercapacitor prepared with this kind of electrolyte To sum up, the design of new electrolyte system and the preparation of safe, wide voltage window, high conductivity and wide application temperature range electrolyte will help to improve the performance of super capacitor Recently, Yan Xingbin, a research team from clean energy chemistry and Materials Laboratory of Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, developed a method for preparing mixed electrolyte By adding acetonitrile to the typical "water in salt" (WIS; 21 m LiTFSI / H 2O) electrolyte, the "acetonitrile / water in salt" (Awis) mixed electrolyte was prepared Compared with wis electrolyte, Awis mixed electrolyte has low viscosity, high conductivity and wide application temperature range At the same time, Awis mixed electrolyte maintains the characteristics of wide voltage window, non combustible and easy to operate Using the AWIS mixed electrolyte, the researchers assembled a safe, wide window, high power supercapacitor Figure 1 Physical and chemical properties of Awis electrolyte (source: Energy & Environmental Science) Figure 2 Electrochemical properties of super capacitor (source: Energy & Environmental Science) This work provides a strategy to prepare a new electrolyte by mixing salt with water / organic solvent, The electrolyte based on this strategy is expected to be used to construct high-performance energy storage devices, such as super capacitors, metal ion hybrid capacitors and metal ion batteries The research work was recently published online in energy & Environmental Science (DOI: 10.1039 / c8ee01040d) The above work has been supported by NSFC, the key cultivation project of the "13th five year" strategic plan of the Chinese Academy of Sciences and the Western light of the Chinese Academy of Sciences