The Interfacial Regulation Of Electrode Materials And Design Of Novel Energy Storage Devices With High Energy Density

The energy crisis is one of the hot topics in the sustainable development of our planet.The construction of high-performance electrochemical energy storage(EES)devices is regarded as a promising approach to optimize the energy structure and promote the energy revolution.At the same time,the exploration of new EES mechanisms is full of importance to build high performance EES devices and realize the leap-forward development of energy storage technology.In this dissertation,the interfacial regulation of the supercapacitor electrodes is systematically studied according to the energy storage mechanisms and electrode structures.Moreover,the category of electrochemical active substances for high energy density EES devices has been expanded and the reaction mechanism of the air pollutant NO2 in EES devices has been investigated in detail.This dissertation provides theoretical and experimental basis for the development of high energy density EES devices.The main results of the dissertation are as follows:(1)The interfacial properties of Fe2O3 are tailored by the construction of g-C3N4/Fe2O3 heterojunction.The band structure and electrochemical performance of the composite material are investigated.The optimization of the electron conductivity and pseudocapacitive performance is realized with the formation of heterojunction.The underlying mechanism of electrochemical kinetic is elucidated;(2)The ionic liquids(ILs)/graphene composites are prepared by covalent and non-covalent interfacial modification strategies.The wettability of ILs/graphene with ILs electrolytes is improved and the self-discharge effect of the electrodes is suppressed.Meanwhile,the defects of carbon-based electrode materials are reduced and the cycling lifespan of ILs/graphene electrode is optimized at a voltage window of 0～4.0 V;(3)The interfacial engineering of carbonaceous fibers is realized by the conformally coating of pen ink nanoparticles.Owing to the high electrical conductivity and abundant macroporous structure,the as-designed flexible substrate can provide sufficient loading room and high ion/electron conductive network for pseudocapacitive materials.Therefore,the loading mass and utilization efficiency of pseudocapacitive materials have been increased simultaneously;(4)The air pollutant NO2 is used as electrochemically active substance to construct a new Li-NO2 battery system.Various methods are conducted to investigate the electrochemical mechanisms and the electrochemical Faraday efficiency of the NO2 reduction in Li-NO2 battery.This novel EES device will inspire new insights into the development of advanced techniques to resolve the energy and environment issues simultaneously.Overall,the design principles of key materials for EES devices with high energy density have been proposed from the aspects of improving the specific capacitance,expanding the device voltage window,structure engineering of fibrous substrates and exploring new energy storage mechanisms.The design and construction of high energy density EES devices are realized.