Study On Electromagnetic And Lithium Storage Properties Of Two-dimensional SnS And NiPS₃

With the development of science and technology in human society,electrochemical power?EPS?plays an increasingly important role in energy storage and conversion.At present,lithium ion battery?LIBs?because of its high specific capacity,no memory effect,high working voltage,long life and other advantages,widely used in electronic equipment and power storage system.Since the performance of lithium ion battery cathode material is the key factor to determine the battery performance,it is of great significance to further develop lithium ion battery cathode material.In recent years,due to its extremely large specific surface area,two-dimensional?2D?materials can provide more delocking channels for lithium ions and enable lithium ions to spread more rapidly,which has become the key research and development direction of LIBs cathode materials.Among them,two-dimensional graphene has been successfully used as a commercial cathode material,but its durability application is limited due to the lithium nucleation on graphene.Two-dimensional phosphene has a very high diffusivity,but it is extremely unstable in the internal environmental conditions of lithium batteries.The theoretical capacity of two-dimensional Ti₃C₂ material is high,but its open circuit voltage is too low.In order to find two-dimensional anode materials with high specific capacity,low diffusion barrier,high open circuit voltage and stability,this paper mainly studies the suitability of two-dimensional SnS and two-dimensional NiPS₃ as LIBs anode materials.In this paper,VASP software based on density functional theory is used to mainly study the electronic structure,diffusion barrier,open circuit voltage and other related properties of two-dimensional SnS and NiPS₃ as anode materials for lithium batteries.Secondly,some basic researches are made on the magnetic introduction of two-dimensional SnS through substitution of doped transition metal?TM?atoms and its stability.The results show that:?1?Li atom can combine with SnS monolayer,and the binding energy is about-2.0ev.After the adsorption of Li by SnS monolayer,a large number of electron doping occurred,leading to the transformation of SnS monolayer from semiconductor to metal.The diffusion barrier of Li in SnS single layer is about 0.45 eV.In addition,the average open circuit voltage of single layer SnS is about 1.98 V.?2?Li atom can combine with NiPS₃ single layer,and the binding energy is about-0.97 eV.The lithium process dopes a lot of electrons into the single layer of the NiPS₃,making the single layer transform from semiconductor to metal.The energy barrier of Li atom diffusion in the single layer of NiPS₃ is about 0.279 eV,which makes quick charging possible.Moreover,the average open circuit voltage of single-layer NiPS₃ as the negative electrode of lithium battery is about 0.55 V,which is very suitable for lithium battery with high charging voltage.The theoretical specific capacity of this material is 608 mAh g^-1.?3?the study of two-dimensional SnS introducing magnetism by substituting doped transition metal?TM?atoms shows that only Mn doped SnS monolayer is a magnetic semiconductor,and the SnS monolayer doped with Ti is transformed into a spin-decomposed metal.In a word,two-dimensional SnS and NiPS₃ are ideal anode materials for the preparation of high-performance lithium ion batteries.The conclusion of this paper can provide some valuable information for the further study of two-dimensional SnS and NiPS₃ as anode materials for lithium batteries.