丙烯酸酯类聚合物在钠离子电池固态电解质中的研究现状与展望

With the continuous development of technology,the demand for energy in human society is increasing day by day. Fossil fuels,as the main source of energy at present,bring about huge carbon dioxide emissions,which exacerbate the greenhouse effect and cause rapid global temperature rise and seriously affecting the global climate. Reducing the use of fossil fuels and developing renewable and sustainable green energy has become a consensus among all the humanity. However,green energy sources such as solar energy, wind energy,hydropower and geothermal energy suffer from temporal and spatial imbalances and instability,making it difficult to meet the sustainable and stable requirements of human society for energy. Therefore,there is an urgent need to increase research on energy storage devices with high energy density and long cycle life to help make up the shortcomings of the green energy that we are suing now. At present,lithium batteries play an important part of large-scale commercial energy storage devices for their good comprehensive performance. They marvelously meet the above requirements while adapt to the needs of the rising industries such as new energy vehicles and smartphones. However,lithium-ion batteries have high costs and the supply of raw materials is difficult to meet the rapidly increasing demand. Reliable substitutes for lithium batteries are needed. Sodium and lithium are located in the same main group in the periodic table with similar chemical properties. Besides,sodium is widely distributed on Earth,thus it is easy to obtain and cost-effective. Sodium ion batteries work in a similar way to lithium-ion batteries. The smaller Stokes radius of sodium ions in solvents helps them achieve higher ion migration rates and numbers,making sodium ion batteries a potential alternative to lithium-ion batteries. Electrolytes,as the medium for ion transport,play an important part of batteries,greatly affecting their overall performance and safety. The electrolyte systems that use organic solvents are widely studied in sodium ion batteries. However,liquid electrolytes are difficult to control the growth of dendrites,resulting in a decrease in the cycling stability and Coulombic efficiency of the battery. Besides,the dendrites piercing through the separator can cause a short circuit in the battery,and may cause serious safety accidents such as leakage of flammable organic electrolytes and explosions. Developing solid electrolytes instead of liquid electrolytes can greatly reduce safety hazards and improve battery performance. Solid electrolytes can be mainly divided into inorganic solid electrolytes,organic solid electrolytes,and composite solid electrolytes according to their composition. The organic polymer solid electrolyte can be divided into gel electrolyte and pure solid electrolyte according to its morphology. Acrylate polymer solid electrolytes have the characteristics of easy availability,wide application, mature process,and good compatibility with electrode materials,making them popular candidate materials for developing new generation secondary batteries with high energy density and safety. Based on this,according to the role of acrylate in electrolyte,this article reviewed the research progress of acrylic polymer electrolytes in sodium ion batteries by dividing them into three categories:acrylate cross-linked copolymer electrolytes,poly-acrylate gel electrolytes,and poly-acrylate composite electrolytes. Acrylate mainly acted as the crosslinking agents in cross-linked electrolytes. While in the poly-acrylate gel electrolytes,the acrylate played the leading role,determining the electrochemical performance of the electrolyte. As for the poly-acrylate composite electrolytes,the acrylate was regarded as the matrix of electrolyte and play an important part of their electrochemical performance. Then their advantages and disadvantages were discussed. The acrylate cross-linked copolymer electrolytes could achieve multiple functions according to different needs,making them adaptable to complex scenarios. However,the electrochemical performance of acrylate crosslinking agents had not been fully utilized. The research on poly-acrylate gel electrolyte mainly focused on polymethyl methacrylate. Their electrochemical performance could satisfy the basic needs of batteries,while poor mechanical performance limited its application. As for the poly-acrylate composite electrolytes,they were the most widely studied acrylate electrolytes for their good comprehensive performance. They combined the advantages of organic and inorganic components,thus possessing excellent electrochemical,mechanical,and processing properties. They could be divided into three categories:composite with other polymers,composite with active inorganic fillers,and composite with inert inorganic fillers. Compositing with other polymers mainly improved their mechanical strength and stability,while compositing with inorganic fillers mainly enhance their ion conductivity. Compositing with inorganic fillers could provide more ion transport pathways,resulting in higher ion conductivity than inert inorganic fillers. However,the proportion of acrylate in composite electrolytes was often less than half,which failed to fully utilize the excellent electrochemical performance of the acrylate matrix. Besides,the influence of acrylate content on electrochemical properties of composite electrolytes was often ignored. More inorganic fillers increased the cost of batteries. Finally,based on the properties of different categories of acrylate electrolyte,this article proposed corresponding optimization strategies and looked forward to their trends of future development.