MXene-based Composite Electrode Design And Its Sodium And Aluminum Battery Performance Study

In order to cope with global climate change and ensure energy security,countries around the world have formulated their own energy technology development plans from the height of energy strategy to promote the development of new energy technologies and industries.In the context of"carbon neutrality"and"carbon peaking",various new energy technologies in China are developing rapidly.While the demand for mobile energy storage devices is increasing,the drawbacks of lithium-ion batteries are gradually emerging.The uneven global distribution of lithium resources and low reserves lead to high prices of lithium-ion batteries and the problem of lithium metal dendrites also makes lithium-ion battery safety issues prominent.Therefore,the development of new battery energy storage system is an inevitable requirement for the further development of new energy technology.Among them,sodium ion battery due to its rich crustal reserves and similar electrochemical properties with lithium ion battery has become the most promising new energy storage system to replace lithium ion battery.Aluminum ion batteries are the most promising new battery system in the future due to their abundant aluminum metal resources,high safety and the highest theoretical volume capacity.Both sodium ion batteries and aluminum ion batteries are currently facing the problems of poor cycling stability and relatively low energy density,while electrode materials are the key to determine the performance of battery energy storage,so the exploration of high-performance electrode materials with reasonable structure can help promote the commercialization of sodium and aluminum ion batteries.In order to solve the problems of cycle stability and low energy density of new battery systems such as sodium and aluminum ion batteries,a new electrode material capable of anchoring the active material needs to be found.Transition metal carbon nitride（MXene）is a new class of multifunctional two-dimensional materials with tunable surface chemistry and metallic conductivity properties.Currently MXene is widely used as an electrode material in various fields due to its physicochemical properties.In these electrodes,MXene can greatly alleviate the capacity degradation caused by active material shedding,swelling and pulverization,and improve the efficiency of active material utilization.In this thesis,MXene is used as a binder and framework material to shorten the charge transfer path,mitigate the electrode damage caused by the swelling of the active material,and improve the utilization efficiency of the active material,and finally achieve the design and preparation of sodium ion battery anode and aluminum ion battery cathode with considerable performance.The main work is as follows:（1）Design and preparation of Nb₂CT_x MXene bonded MoS₂ hollow microspheres for sodium ion battery anode.Nb₂CT_x MXene was used as a bond to connect the MoS₂hollow sphere sodium ion anode active material,and an one-dimensional flexible sodium ion battery based on Nb₂CT_x/MoS₂@CS was finally designed.The physical properties of the Nb₂CT_x/MoS₂@CS anode material were analyzed using a series of physical characterization and the sodium ion storage properties of the Nb₂CT_x/MoS₂@CS anode were investigated using electrochemical test equipment.The sodium ion battery assembled with the Nb₂CT_x/MoS₂@CS anode exhibited excellent reversible sodium storage performance.（2）MoS₂ three-dimensional interconnected sodium ion battery anode with Nb₂CT_xMXene as a framework was designed and prepared.A three-dimensionally interconnected Nb₂CT_x@MoS₂@C anode material was successfully synthesized by using Nb₂CT_x MXene as the framework material through hydrothermal in situ growth of MoS₂ nanosheets on the framework and in situ polymerization of carbon nanospheres by DA on its surface.When the current increases from 0.1 to 1 A g^-1 Nb₂CT_x@MoS₂@C anode can achieve an excellent capacity retention efficiency of 88.4%.This 3D interconnected Nb₂CT_x@MoS₂@C material exhibits high rate performance,high reversible capacity,and high stability in sodium ion batteries.（3）Design and preparation of a Sn S sodium ion battery anode anchored to a Nb₂CT_x MXene framework.A C@Sn S@Nb₂C/Nb₂O₅ three-dimensional nanoflower-shaped sodium storage anode material was successfully synthesized by homogeneous in situ growth of Sn S nanoparticles using highly conductive Nb₂CT_x as a framework.The synthesis process of C@Sn S@Nb₂C/Nb₂O₅ sodium ion battery anode is simple and has excellent cycling and rate performance,which is beneficial for sodium ion battery technology development and application.（4）Design and preparation of CoSe₂ nanoparticle arrays based on Ti₃C₂T_xframework for aluminum ion battery cathodes.A CoSe₂ nanoparticle arrayed aluminum ion cathode material with high voltage plateau and rate performance was designed and synthesized based on the MXene lamellar framework.The CoSe₂@TiO₂/Ti₃C₂ cathode material exhibited a high charge/discharge voltage plateau and stable reversible cycles.