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Shanxi Coal Chemical has made a series of progress in energy storage carbon materials and devices
[ Instrument R & D of Instrument Network ] In recent years, in the research and development of energy storage carbon materials and devices, researcher Chen Chengmeng led the 709th group of the Shanxi Coal Chemistry Institute of the Chinese Academy of Sciences to make a series of progress. The team solved a series of scientific problems in the preparation and application of energy storage carbon. Through collaborative innovation in industry, academia and research, it broke through the core technology of large-scale production of energy storage carbon materials such as graphene, capacitor carbon and spherical graphite, and designed and assembled supercapacitors and lithium ions. Energy storage devices such as batteries and lithium-sulfur batteries form application demonstrations for electric vehicles, road stud lights, and drones.
The supercapacitor is a new type of component that stores energy through the interface double layer formed between the electrode and the electrolyte. When the electrode is in contact with the electrolyte, due to the Coulomb force, intermolecular force and interatomic force, the solid-liquid interface has a stable double charge with opposite signs, which is called the interface double layer. Think of the electric double layer supercapacitor as two inactive porous plates suspended in the electrolyte, and the voltage is applied to the two plates. The potential applied to the positive plate attracts negative ions in the electrolyte, and the negative plate attracts positive ions, thereby forming an electric double layer capacitor on the surface of the two electrodes. According to different electrode materials, electric double layer capacitors can be divided into carbon electrode double-layer supercapacitors, metal oxide electrode supercapacitors and organic polymer electrode supercapacitors.
Lithium-ion battery is a kind of secondary battery (rechargeable battery), which mainly relies on the movement of lithium ions between the positive electrode and the negative electrode to work. In the process of charging and discharging, Li + intercalates and deintercalates between the two electrodes: when charging, Li + deintercalates from the positive electrode, intercalates into the negative electrode through the electrolyte, and the negative electrode is in a lithium-rich state; the opposite is true during discharge.
Lithium-sulfur batteries are a type of lithium batteries, and are still in the scientific research stage as of 2013. Lithium-sulfur battery is a kind of lithium battery with sulfur element as the battery positive electrode and metal lithium as the negative electrode. Elemental sulfur has abundant reserves in the earth, and has the characteristics of low price and environmental friendliness. Lithium-sulfur batteries that use sulfur as the cathode material have a higher theoretical specific capacity and the theoretical specific energy of the battery, respectively reaching 1675m Ah / g and 2600Wh / kg, which is much higher than the capacity of commercially widely used lithium cobalt oxide batteries ( <150mAh / g). And sulfur is an environmentally friendly element, basically no pollution to the environment, is a very promising lithium battery.
The structural evolution mechanism from the conversion of organic precursors such as biomass and macromolecules to inorganic carbon materials, and the structure-activity relationship between the microstructure of the materials and the electrochemical performance are the common key scientific issues of controllable preparation and directional application of energy storage carbon.
The team explained the main / side chain competition reaction and the carbon-carbon bond breaking and bonding mechanism during the crosslinking of starch molecules, which provided a scientific basis for the controlled conversion of biomass to capacitive carbon (ACS Sustainable Chem. Eng., 2019, 7 , 14796-14804); studied the evolution path of oxygen-containing functional groups during thermal reduction of biomass and phenolic resin-based capacitor carbon or hard carbon, and established correlations with their performances such as supercapacitors and lithium-ion batteries, as the surface structure of energy storage carbon materials Optimization indicates the direction (J. Energy Chem., 2020, JECHEM1233; Electrochim. Acta, 2020, 337, 135736-11; J. Energy Chem., 2018, 27, 439-446); explains the activation of phosphoric acid on the surface of porous carbon The chemical mechanism of phosphorus doping, and found its stabilizing effect on the electrochemical interface, provides a new idea for the surface structure design of high-voltage capacitor carbon (ACS Appl. Mater. Interfaces, 2019, 11, 11421-11430; Electrochim. Acta, 2019, 318, 151-160; Electrochim. Acta, 2018, 266, 420-430.).
The team also reviewed the domestic and foreign scientific research progress and development trends in the field of biomass-based capacitor carbon and phenolic resin-based carbon aerogel (J. Mater. Chem. A, 2019, 7, 16028-16045; Micropor. Mesopor. Mater. , 2019, 279, 293-315.).
The team of Chen Chengmeng cooperated with Jinneng Group, Meijin Group and Shanxi Sanwei and other enterprises to overcome the pilot test technology of ton-scale redox graphene, ten-ton biomass-based capacitor carbon and ton-scale coal-based spherical graphite, and open up a full set of technological processes. The development of supporting key equipment has realized the leap of related materials from "sample" to "product". The team's pilot test preparation technology for graphene has passed the Shanxi Scientific and Technological Achievement Appraisal, and the products have been widely used in more than 100 domestic and foreign enterprises and research institutions such as the 18 CEC, 42 Aerospace Science and Technology, and China Aviation Development Beijing Aviation Materials Institute. Capacitive carbon pilot products have successfully passed the application evaluation of domestic capacitor leading companies such as Ningbo CRRC, Jinzhou Kaimei and Shanghai Aowei. Recently, the team has cooperated with Meijin Energy to start the first phase of an annual output of 500 tons of capacitor carbon industrialization project, and it is expected to produce batches of qualified products in 2021.
In order to serve the accurate and efficient research and development of energy storage carbon materials, Group 709 has built an international advanced electrochemical energy storage device assembly and evaluation platform. Relying on independent carbon materials, we designed and assembled advanced energy storage devices such as supercapacitors, lithium-ion batteries, and lithium-sulfur batteries, and formed application demonstrations for road stud lights, electric vehicles, and drones. Through the integration of upstream and downstream resources, the transition from "unit matching" to "system integration" has been achieved. While feeding back and guiding the optimization of the material process, it has realized the precise docking of the needs of the energy storage industry. At present, the team has established close cooperative relations with Ningbo CRRC, Ningde Times, Saudi Basic Industries Corporation, Xiamen University, Institute of Aerospace Information Innovation, Chinese Academy of Sciences and Dalian Institute of Chemical Physics.
Source: Encyclopedia, Shanxi Coal Chemistry Research Institute