Progress in research on new hybrid capacitors of Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences

[ China Instrument Network Instrument Development ] Hybrid capacitor technology "internal crossover" of secondary batteries and supercapacitors, combining high energy density, high power density and long life. Currently, lithium ion hybrid capacitors have been commercialized. However, insufficient and uneven distribution of lithium resources will limit the large-scale application and sustainable development of lithium-based energy storage devices. Sodium-potassium is rich in resources, widely distributed, and low in price. Similar to the physical and chemical properties of lithium, sodium-potassium ion energy storage devices are expected to become potential substitutes for lithium-based energy storage systems. In recent years, key materials and related technologies have developed rapidly.

Figure 1 Double carbon sodium ion hybrid capacitor

Figure 2 Double carbon potassium ion hybrid capacitor

Figure 3 candle gray negative double carbon potassium ion hybrid capacitor

Yan Xingbin, a researcher at the Clean Energy Chemistry and Materials Laboratory of the Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, has been working on new carbon materials and energy storage devices, and has developed a series of new dual-carbon high-performance metal ion hybrid capacitors.

The researchers used a thermo-solid phase sintering to prepare a three-dimensional network carbon material, and obtained a key preparation technology for network carbon materials. Further, a porous three-dimensional network carbon material (positive material) with excellent capacitance characteristics was prepared by chemical activation technology. By utilizing the characteristics of stable electrochemical properties, excellent electrical conductivity and good compatibility with electrolytes, the double-carbon system electrode materials have optimized the quality and kinetic matching characteristics of the positive and negative active materials, and finally constructed a high energy density and power density. A double carbon sodium ion hybrid capacitor with excellent cycle stability (as shown in Figure 1), and the results are published in Adv. Energy Mater. 2018, 8, 1702409.

Recently, researchers have used carbon sodium as a template to synthesize carbon nanosheet anode materials by chemical vapor deposition (CVD) technology. The carbon nanosheets have good conductivity, rich defects, large interlayer spacing, and rich oxygen, which are beneficial to ions. Storage and transfer. As a negative electrode material, the carbon nanosheet exhibits excellent potassium ion storage characteristics and lays a foundation for constructing a high performance potassium ion hybrid capacitor. Therefore, the researchers constructed a potassium-ion hybrid capacitor using a carbon nanosheet anode material and a high-capacity nitrogen-doped three-dimensional carbon cathode material (as shown in Figure 2). Through material design and device optimization, the hybrid capacitor has excellent performance, high energy density (149 Wh kg-1) and high power density (21 kW kg-1), as well as good cycle stability (80% cycle of 5000 cycles) rate). The results are published online at Adv. Energy Mater. 2019, 1803894.

At the same time, the researchers also used the most commonly used candles as raw materials, prepared onion carbon anode materials by simple combustion method, and assembled high-performance double-carbon potassium-ion hybrid capacitors (as shown in Figure 3). J. Mater. Chem. A, 2019, http://dx.doi.org/10.1039/C9TA01653H.

The above work was funded by the National Natural Science Foundation of China, the Lanzhou Institute of Technology's “First Three-Five” Strategic Planning Key Cultivation Project, and the Chinese Academy of Sciences Clean Energy Innovation Research Institute Cooperation Fund Project.

(Original title: Progress in the research of new hybrid capacitors of Lanzhou Institute of Chemical Technology)