Controllable Preparation Of MOF Based Flexible Electrode Material And Its Application In Bendable Energy Storage Devices

With the rapid increase of traditional fossil energy consumption,water pollution and air pollution have seriously affected human daily life.Green,safe,efficient and sustainable energy has become the focus of people's attention,so we need efficient energy storage devices.Rechargeable battery,as a reliable electrochemical energy storage device,has attracted people's attention.However,with the increasing demand for multifunctional intelligent devices,electronic devices with the characteristics of flexibility,safety,light weight,high energy storage,long life and mechanical stability have become the main development trend of energy storage devices.At present,the electrode materials of rechargeable battery are mostly prepared by traditional pressing process and adding binder.There are some problems such as poor cycle stability,low energy density and non bending,which limit its practical application in flexible energy storage devices.How to develop electrode materials with high stability,flexibility and energy density has become the key,which is of great scientific significance for the development of micro flexible energy storage devices.Metal-organic frameworks?MOFs?are mainly formed by the coordination of metal ions/ion clusters and organic ligands through complexation.They have the characteristics of large specific surface area,adjustable pore structure,and have great potential in selective catalysis,gas storage,chemical separation and drug delivery.In addition,porous carbon composites and porous metal oxides prepared by MOFs are also widely used in clean energy storage and conversion systems.In this paper,MOFs derived transition metal materials are taken as the research object,and related work is carried out around the controllable preparation and assembly of MOFs derived materials and their application in flexible bendable energy storage devices.In this paper,MOFs derived transition metal materials are taken as the research object,and the related work is carried out around the controllable preparation of MOFs derived materials,the controllable assembly of low dimensional nano materials and the application in flexible bendable energy storage devices.The specific research contents are as follows:?1?A general and simple wet spinning method was developed to realize the controllable preparation of MOF/graphene oxide?GO?composite fiber.The composition and structure of the derivative porous metal oxide/reduced graphene oxide?r GO?composite fiber were controlled by controlling the experimental conditions.The effects of time and temperature on the composition and structure of porous metal oxide/r GO composite fibers and its effect on the performance of lithium storage.The porousGO composite fiber has high specific capacity(846.9 m Ah g^-1 after 200cycles at 0.5 A g^-1),excellent rate performance(745.0 m Ah g^-1 at 2 A g^-1),good long cycle stability(98.6%after 500 cycles at 5 A g^-1)and good flexibility.The excellent properties ofGO composite fiber are attributed to the following two aspects:the porous structure derived from MOFs improves the mass transfer performance and promotes the electrochemical reaction kinetics;the graphene nanosheet coated on the porous metal oxide can not only provide a conductive network for electronic transmission,but also prevent the aggregation of metal oxide.?2?The controllable preparation of Cobalt selenide nanosheet/nitrogen-doped carbon nanotubes?CoNSA?on carbon cloth was realized by simple hydrothermal synthesis and two-step calcination.The CoNSA showed good hydrogen evolution reaction?HER??oxygen evolution reaction?OER?and oxygen reduction reaction?ORR?performance.When the electrode was used as positive material of zinc air battery,it showed high performance of liquid and flexible zinc air battery.The liquid zinc air battery based on CoNSA air cathode showed excellent long-term stability in 235 hours,superior to Pt/C+Ir O2 electrode.The flexible zinc air battery with CoNSA as self-supporting electrode shows excellent mechanical flexibility and durability in a wide temperature window?0-40??.The excellent performance of CoNSA can be attributed to the well-designed structure,which can optimize the intrinsic catalytic activity,improve the conductivity,enhance the structural stability and enhance the electrode electrolyte interaction/interface area.