Preparation and Capacitance Performance of Carbon-based Electrode Materials for Electrochemical Capacitors
|Keywords||Electrochemical capacitors Pore ??structure Nanocrystalline carbon SEI - like film Pseudo-capacitance|
In this paper, the development of low-cost, high specific energy and high specific power electrochemical capacitors carbon electrode material for the purpose of research work carried out with phenolic resin, petroleum coke and melamine resin as carbon precursor prepare high-performance carbon electrode material, carbon Preparation of the electrode material, the structure, the behavior of the capacitors and energy storage mechanism conducted in-depth research. In this thesis, first proposed thermosetting phenolic resin as raw material, CO2 physical activation Preparation of low-cost carbon electrode material, the activation temperature and activation time of phenolic resin-based activated carbon structure and behavior of the capacitors. Under optimal experimental conditions for preparing phenolic resin-based porous carbon having more than 2200m2 / g of specific surface area, the pore size distribution in the 1 ~ 2 nm, in a 30wt% KOH aqueous solution having up to 211.6F / g of specific capacitance, good power characteristics and cycle performance. Using KOH chemical activation phenolic resin-based porous carbons prepared by different specific surface area and pore size distribution was investigated in 30 wt% KOH solution and 1M Et4NBF4/PC, electrolyte capacitor performance. The research results show that: the phenolic resin-based porous carbon does not exist in the aqueous electrolyte ion screening \stars \KOH activation of petroleum coke preparation of nanocrystalline carbon raw materials pre-carbonization and activation temperature on the structure and capacitance performance, and discusses the practical use of the possibilities and new energy storage mechanism. It was found that: appropriate combination of carbonization and activation process can be achieved on the the nanocrystalline carbon pore structure and crystalline structure of the regulation; the obtained nanocrystalline carbon maintain a low specific surface area, large layer spacing and high electrode density, and excellent at the commodity activated carbon YP15 the capacitor performance. Galvanostatic charge-discharge and semi-situ XRD analysis showed that the substance of the electrochemical activation of electrolyte ions embedded in the ordered or unordered carbon microcrystalline layer process. Observed within the nano-graphite microcrystalline carbon carbon microcrystalline layer spacing increases and surface formation of SEI film in an orderly manner, combined with scanning electron microscopy and EDS EDS analysis proposed for the first time by high resolution projection microscope (HRTEM) nanocrystalline carbon plug layer energy storage mechanism. For the first time the direct carbonization commercial production of melamine resin preparation of nitrogen-rich carbon materials for electrochemical capacitor electrode material. The study found: smaller than the surface area of ??the nitrogen-enriched carbon (102.6m2 / g), having a mass ratio of up to 205.5F / g capacitors, a good power performance and excellent cycle stability. Than the capacitance and XPS analysis showed that the quasi-capacitance related to the role of a good capacitor performance with nitrogen-rich carbon material surface pyrrole nitrogen or Hydroxypyridine of nitrogen.