Preparation Of Self-supporting Carbon Nano-foam Electrode Materials And Its Application In Energy Storage Technology

With the rapid development of science and technology,the demand for energy is also increasing.Traditional fossil fuels not only have limited reserves,but also have a great impact on the environment after combustion.At present,green energy represented by photovoltaic power generation and wind power generation has attracted extensive attention.However,these energies are limited by natural conditions,and the released energy needs to be stored to meet the demand for energy when the environment is affected.This requires the development of advanced energy storage devices to solve this problem.At present,a large number of researchers have done a lot of research on supercapacitors and lithium ion batteries and other energy storage devices.With their excellent performance and low cost,they have been widely used in various fields.However,they also have many problems,such as poor electrical conductivity,low capacity.In order to solve the above problems,carbon nanomaterials and carbon nanocomposites were prepared by chemical vapor deposition and hydrothermal methods,and were applied to the electrodes of lithium ion batteries and supercapacitors,showing good electrochemical properties.The main research results of this thesis are as follows:?1?Three-dimensional carbon nanotube foam?3D-CNTF?materials were prepared by chemical vapor deposition with CO₂ as carbon source.The activation of growing CNTF with a certain concentration of KOH aqueous solution showed that the activation could expand the specific surface area by generating new pores from micropores to macropores,but the shape and size of CNTF did not change much.We used activated CNTFs as the electrodes of supercapacitors and lithium ion batteries respectively,which can significantly improve the specific capacity and multiplier.This is because CNTFs has a layered porous structure and the activated material has a larger specific surface area.Using the prepared 3D carbon nanotube foam as the substrate,the precursorof CNTF@CoO composite material CNTF@Co?OH?₂ was firstly prepared by hydrothermal reaction,and then a new core-shell structure CNTF@CoO composite material was obtained by annealing.Electrochemical tests show that the composite has good electrochemical properties.It shows good multiplier performance and long cycle stability.During charging and discharging,the reversible capacity of CNTF@CoO electrode reaches 820 mAhg^-11 at the current density of 100mAg^-1,and 448 mAhg^-11 after 1000cycles at the current density of 5000mA g^-1.In composite materials,CoO provides a high capacity,while carbon materials with porous structure and high conductivity not only provide a fast ion transport channel,but also play an effective buffering role in the process of charging and discharging.