Graphene Based Two-dimensional Materials For Energy Storage And Conversion

The wide application of graphene-based two-dimensional materials in fuel cells,supercapacitors and electro-catalysis hydrogen production provides challenges and opportunities for solving the problem of modern energy shortage.Graphene itself has great potential in the direction of storage charge and hydrogen production because of its high conductivity,high specific surface area and mechanical flexibility.At the same time,it also promotes the application of other graphene-like two-dimensional materials in energy storage and conversion.For energy storage equipment,supercapacitors become the alternative due to the higher energy density,meet the requirements of rapid charge and discharge,and have a long cycle life.The green development mechanism of electro-catalysis hydrogen production makes it the main means for the preparation of sustainable hydrogen fuels.The core of any new energy storage and conversion device is to design electrode materials with excellent performance.In this paper,graphene-based and graphene-like two-dimensional materials are synthesized and applied to energy storage and conversion.The main research contents are as follows:In this work,we mainly aim at graphene oxide and charge transfer salt composite film,using laser etching technology to design the inter-digital electrode,and then explore the performance of micro supercapacitor.First of all,graphene oxide was prepared by improved Hammer method and charge transfer salt?TTF-TCNQ?was prepared by the one-step method.Then the inter-digital electrode was prepared by magnetron sputtering and laser etching,and finally,the device was assembled.The hetero-structure of this kind of micro-supercapacitor gives it excellent high frequency and fast response,so the micro-supercapacitor can be used as an AC line filter device.In the case of 120 Hz,the phase angle can reach 73.2 °,and the relaxation time of the capacitor is 0.32 seconds at the characteristic frequency of 3056 Hz.In addition,the micro-supercapacitor prepared by this method has excellent rate performance,flexibility and stability,and the scanning speed can reach 1000 V.After 10000 cycles,the capacitance stability of the micro-supercapacitor is more than 98%.When the current density is 0.04 m A cm^-2,the areal capacitance of the micro-supercapacitor is as high as 27.2 m F cm^-2,and the charge and discharge performance of the micro-supercapacitor is significantly higher than that of the micro-supercapacitor reported before.It is expected to be a candidate material for AC line filtering and corresponding miniaturized electronic products.The main purpose of this work is to improve the zero band gap structure of graphene.Using HAT-CN as the precursor,nitrogen-rich graphene two-dimensional material?C₂N?was obtained by one-step direct calcination in a nitrogen environment.Then four different metals were selected for coordination and applied to electro-catalysis hydrogen production.First of all,we design and synthesize a kind of HAT-CN,with electrical defect,rigid,planar and aromatic disk system,which has excellent p-p stacking ability and remarkable oxidation resistance.Nitrogen-rich two-dimensional material?C₂N?with periodic void structure was obtained by calcination of its powerful supramolecular aggregation and self-assembled crystal structure and then coordinated with different metals for electro-catalysis hydrogen production.Among them,the electro-catalysis hydrogen production performance of C₂N-Ru is better than that of commercial Pt/C and maintains excellent electro-catalysis stability.When tested under 10 m Acm^-2 for 10 h,the electro-catalysis performance remains basically unchanged.This nitrogenrich graphene-like two-dimensional material is better than exposure to more electro-catalysis activity is expected to replace the expensive Pt in electro-catalysis hydrogen production.