Research Of Surface Adsorption And Diffusion Properties Of Two-dimensional Materials Based On Ion Batteries Applications

With the rapid development of information age,people's demand for rechargeable energy storage equipment is increasing day by day.At present,most of the research is devoted to developing new batteries with excellent performance or electrode materials with high energy density.In recent years,two-dimensional?2D?layered materials have become an ideal alternative electrode material for a new generation of rechargeable batteries due to their excellent electrochemical properties and high surface ratio.At the same time,with the continuous development and progress of computer hardware,the first-principles calculation method based on density functional theory?DFT?plays an indispensable role in predicting the structure and studying properties of new two-dimensional materials.In this paper,the application of new 2D layered materials antimonene,semiconductor boropene and?-SiO₂ in ion batteries is systematically studied by using the first principles method.A brief introduction as follows:?1?Study on the adsorption and diffusion characteristics of alkali metal atoms on2D antimonene surface.Antimonene,indirect band gap semiconductor,band gap is about 1.08 eV,with high carrier mobility and good chemical stability.Calculation results show that Li,Na and K atoms have a high adsorption energy?Li:-2.36 eV,Na:-1.84 eV,K:-1.60 eV?and a small diffusion barrier?Li:0.09 eV,Na:0.08eV,K:0.04eV?on the surface of antimonene,so they can rapidly diffuse on the surface of antimonene without agglomeration.In addition,when electric field perpendicular to the surface of 2D antimonene is introduced,the adsorption behavior can be effectively enhanced.The adsorption energy and transfer charge increase linearly with the increase of the applied electric field,and the effect of the applied electric field on K atom is the most obvious.?2?Investigation on the properties of 2D semiconductor borophene used as cathode material for lithium ion batteries and sodium ion batteries.The band gap of semiconductor borophene is 0.74 eV,and it could be induced with a linear tuning by the mechanical biaxial strains within a small region.Furthermore,the 2D borophene has high dynamic and thermodynamic stability.The study results show that Li and Na atoms had higher adsorption energy?Li:-1.62 eV,Na:-1.41 eV?when adsorbed on the surface of borophene,which could better avoid metal atom agglomeration,thus laying a foundation for inhibiting dendrite growth.At the same time,when Li and Na atoms diffuse on the surface of borophene,they have a small diffusion barrier?Li:0.4eV,Na:0.22 eV?,which provides a possibility to improve the charging and discharging efficiency of the battery.With the increase of adsorbed atoms,borophene shows metal characteristics.When the most stable adsorption sites on its surface were completely covered by Li/Na atoms,the average open circuit voltage of lithium ion and sodium ion batteries was 1.11 V and 0.88 V respectively.And the theoretical specific capacity was 1239.56 mAh g^-1.Further studies on ab-initio molecular dynamics simulations show that the whole semiconducting borophene structure of saturated adsorption could be stable even at temperature of 400 K.?3?The research of 2D?-SiO₂ as a lithium battery anode protection layer.?-SiO₂is an insulating material with an electronic band gap larger than 5 eV,and is also a superhard material with a large young's modulus,which has strong anisotropic mechanical properties and high thermodynamic stability.The research findings show that when Li atom is adsorbed on the surface of?-SiO₂,it has a relatively large adsorption energy?-1.23 eV?and a smaller surface diffusion barrier?0.08 eV?.However,when Li atom passes through the pristine?-SiO₂ material,it has a large diffusion barrier?2.24 eV?.It was found that the diffusion barrier across the material could be effectively reduced after the defect was introduced?O defect:1.96 eV,Si defect:0.52 eV?,which improves the conductivity of metal ions.Finally,the interface properties of Li?110?/?-SiO₂ are discussed,and it is found that when the metal anode surface is covered with two layers of?-SiO₂,the electrons could be prevented transfer from the electrode to the electrolyte.