Biological Micro-tube Based Three-phase Composite High-performance Electrode Material

With the depletion of fossil energy,environmental pollution has become increasingly serious,and sustainable development of new energy has become a strategic focus of the world's attention.However,due to the decentralized distribution of new energy sources and the great limitation of natural conditions,it often leads to fail to meet people's needs.Therefore,the bottleneck problem of new energy development has gradually shifted from the development of new energy to the storage and management of new energy.Unfortunately,the current civilian energy storage systems represented by lithium batteries are not able to meet people's needs.Therefore,some new energy storage systems such as electrochemical capacitors,also known as supercapacitors,are gradually attracting attention from researchers.In order to make the prepared supercapacitor electrode material have high specific capacitance and good cycle life,and at the same time ensure low material cost and no pollution to the environment,this experiment adopts the biotemplate method to prepare high-quality carbon materials in a very simple way to form the supercapacitor electrode material for the limiting action.The experiments in this dissertation are mainly divided into three parts.The stems of rapeseed were used as the carbon source to prepare Carbon tube materials?represented by C?by high-temperature calcination method.CeO₂-NiO,CeO₂-MnO and CeO₂-NiO-Mn₃O₄ were used as the load respectively to obtain a carbon-based composite material prepared by the constant temperature hydrothermal method.It is desired to obtain a carbon-based composite material having a higher specific capacitance retention ratio and superior electrochemical performance.The results showed that the highest specific surface area was up to 350 m² g^-1 and the particle size was about 10-20 nm.The internal resistance of the prepared electrode was 6 ohms.Electrochemical test results are shown as follows:For a 1 mol L^-1Na₂SO₄ solution,the highest specific capacitance of the electrode material reached 237.1 F g^-1 at a current density of 1 A g^-1,and the capacitance was maintained at 85%over 1000 cycles of charge and discharge tests.What is the highest specific surface area with lanthanum-manganese as the load 289 m² g^-1.The internal resistance of the electrode is 6.8 ohms.Electrochemical test results show that when the concentration is 1 mol L^-1Na₂SO₄ solution,the current density is 1 A g^-1.The highest specific capacitance of the electrode material reaches 220 F g^-1.After 1000 cycles of charge and discharge tests,the capacitance is kept at 82%.With Ge-Ni-Mn as the support,the maximum specific surface area reaches 380 m² g^-1,and the particle size is about 20 nm.The obtained internal resistance of the electrode is 2.64ohms.Electrochemical test results show that 1 mol L^-1Na₂SO₄ solution,with a current density of 2 A g^-1,reached 208.33 F g^-1.After 1000 cycles of charge and discharge tests,it still showed high electrochemical performance,and the specific capacitance was always kept at 84%.In summary,the carbon nanotube material prepared by using the rape stalk as a biological template has a large specific surface area,and the nano-crystals prepared by using the self-assembled biologically-graded porous carbon material as a skeleton have a uniform particle size and the samples are composite-loaded.The electrochemical performance of the metal oxide nanocrystalline carbon nanotube electrode material is superior to that of a single loaded electrode material.In addition,there are resistances among composite loads of multiple metal oxides and the composite load,which successfully prevented the single component from agglomerating into large particles,so that the size of the metal oxide nanocrystals deposited on the surface of the carbon tube material is very small,and basically remained at 10-20 nm around.Furthermore,there is still a lot of work to be done to control the particle size of metal oxides and the types and ratios of metal oxides.In later studies,it is possible to explore the use of more excellent metal oxides for composite loads for the purpose of improving the electrochemical properties of the electrode material significantly.