Preparation And Energy Storage Mechanism Of Ultrathin Metal Oxide Nanocomposites

The growing demand for energy has triggered a shift in approach from fossil fuels to renewable sources such as wind and solar power.However,these renewable energy sources are intermittent in nature,making the development of viable storage devices crucial.Electrochemical energy storage is considered a highly efficient energy storage technology because of its high energy conversion efficiency,relatively compact size and fast response.Currently,are common in the market of portable electrochemical energy storage device for lithium ion batteries,however,there are still many problems restrict the further development of the lithium ion batteries,such as metal oxides in the intercalated-Li and Li off will happen in the process of volume expansion,resulting in a piece of pulverization,reduce the service life of the battery.The cost of lithium is high,so it is urgent to develop new secondary batteries(such as sodium ion batteries and potassium ion batteries)to solve this problem.At present,the nanostructured electrode materials of sodium ion batteries in the research and development stage are generally low in load,which affects their commercialization process.Therefore,in order to further improve the electrochemical performance of lithium/sodium ion batteries,it is extremely urgent to develop high-performance anode and cathode materials.In recent years,two-dimensional(2D)heterogeneous nanocomposites have become a research hotspot in the field of nanomaterials because of their excellent properties.Many two-dimensional heterogeneous nanocomposites have shown very good application performance in many application fields,especially in energy storage and conversion.In order to solve the problems mentioned above,we first synthesized metal oxide and go two-dimensional heterogeneous nanocomposites,and then used graphene's low-temperature self-assembly properties to load the two-dimensional nanocomposites onto three-dimensional porous graphene.Among them,the heterostructure in direct contact with the surface can mitigate the volume expansion of metal oxides in the charging and discharging process to the maximum extent,while porous graphene,as a 3D cross-linked conductive skeleton,can provide excellent conductivity and enhance ion transfer rate,which is convenient for the premise of high loading of electrode materials.The battery with high energy density,high power density and long cycle life was obtained.The details are as follows:In Experiment 1,Sn O₂/3D-HGF nanocomposites were synthesized by in-situ chemical synthesis.The prepared Sn O₂/3D-HGF electrode maintained a discharge capacity of 207 m Ah g^-1 after 450 cycles at a high load of 9.0 mg cm^-2.In Experiment 2,flake Zn-co bimetallic oxide/porous graphene composites were synthesized by alkaline template etching.The Zn-Co LDO/HGF electrode prepared by this method still maintained a discharge capacity of about1150 m Ah g^-1 after 130 cycles.