Research On Structure Regulation Of Transition Metal Micro-nano Material And Performance Of Supercapacitor

As a new type of energy storage device,supercapacitors are considered to have great potential for development due to their rapid charge and discharge efficiency,excellent cycle performance and high power density,which can satisfy the market's extensive requirements for energy storage devices.Electrode materials as the core component of supercapacitors,its chemical composition and structure shape directly determine the performance of the entire component.This article will select the nickel-based,manganese-based and cobalt-based compounds as research objects,based on the small size effect,surface effect and synergistic effect,respectively.The structure-effect relationship between electrode materials and electrochemical performance was explored from the structure of the electrode material arrangement,its own structural characteristics and internal structural properties in three aspects.Thus would provide a theoretical basis for the development of new high-performance,transition metal-based electrode materials.The main contents are as follows:1.First of all,the effect of the uniformity of the particle size of the electrode material arrangement on the electrochemical performance is investigated.The use of citrate capping reagents controls the production of nickel bicarbonate nanocrystals with a uniform degree of particle size.When the electrode is fabricated,the homogeneous nickel bicarbonate crystals accumulate stacked to form a porous structure can provide more space and higher specific surface area.Heterogeneous nickel bicarbonate crystals facilitate the formation of a 'dead space' in the formation of electrodes,inhibiting ion and electron transport Therefore,nickel bicarbonate nanocrystals with a more uniform particle size exhibited more excellent capacitance performance(specific capacity of 1596 F/g at 2 A/g)and higher rate performance(at 30 A/g).Capacity retention is 75%)and excellent cycle stability(capacity retention up to 80% after 1000 cycles of charging and discharging).2.Explore the influence of the structure of the electrode material itself on the electrochemical performance.Nickel hydroxide was selected as the research object,and the regulation effect of the additive was used to make it have different thickness and thickness(2D)structure.The thinner lamellar structure not only has a larger specific surface area,but also exposes more redox active sites,shortens the ion transport path and lowers the electron transport rate.Therefore,the higher specific capacity is shown to reach 2300 F/g at a current density of 1 A/g,and the high rate performance can still reach about 1800 F/g at 30 A/g,and the capacity retention rate reaches 77%.3.Study the relationship between the changes in the internal structure of the electrode material and the changes in electrochemical properties,and in-depth explore the structure-effect relationship.With the change of cobalt ion doping concentration,the valence state of manganese and cobalt in the sample shows a regular change and is mainly divided into three crystal phases.Different valence states in different crystal phases directly affect the crystal.The structure causes changes in the topography.Therefore,the electrochemical performance of the sample also showed a regular change.When the cobalt ion incorporation concentration was 60%,the sample exhibited the most excellent capacitance performance,and its specific capacitance at a current density of 0.2 A/g was achieved.308 F/g;when the incorporation concentration is between 50% and 70%,the cycle stability of the sample is more excellent.After the current density is 1 A/g after 10000 charge and discharge cycles,the capacity retention rate can still reach 90%.