Preparation Of Tin-based Phosphide And Its Electrochemical Energy Storage Performance

Since the 21st century,the unevenness of energy supply and demand have become more serious,and the impact of energy shortages has become more and more serious.However,the development and utilization of fossil energy has caused irreversible environmental pollution and global climate problems.More and more attention should be paid to the development and utilization of green energy.Among existing energy storage technologies,lithium ion batteries(LIB)have excellent energy density and versatility.Since the commercialization of LIB in the 1990s,the rapid development of portable devices has greatly promoted the growth of LIBs.Due to the uneven distribution and limited reserves of LIB raw materials,we continue to look for alternative energy storage chemicals.Sodium ion battery(SIB)is currently one of the most promising energy storage technologies to replace LIB.In the past few decades,there has been a great deal of increase in research on sodium ion batteries(SIB)worldwide.It is attributed to the fact that both sodium and lithium belong to the same family of elements,which are called alkali metal elements.Besides,the resources of sodium are abundant on earth.Although SIB has the ability to approach LIB in terms of specific capacity,it is considered to be a cost-effective power supply solution for large-scale grid energy storage due to its low cost and relatively easy availability.Compared with cathode materials,anode materials,as the main body of sodium storage,play a vital role in SIB.Therefore,finding a high-capacity and stable SIB anode material is the focus and hotspot of current research.The common SIBs anode materials are transition metal oxides,sulfides and so on.This paper focuses on the advantages and disadvantages of common transition metal compounds(such as oxides,phosphides,etc.),combined with some of the current excellent conductive base materials(such as carbon fiber cloth,MXene).The composition,morphology and structure of the electrode are modified in order to enhance its electrochemical energy storage performance,the specific research work is as follows:1.Transition metal phosphides have excellent electrochemical energy storage performance and show good research prospects in the application of sodium ion batteries.However,in the actual research process,it is discovered that transition metal phosphides have slow kinetics and easy expansion in volume,which cause them to face some problems in the application of SIB.We have synthesized a tin-based phosphide,which is obtained by loading Sn P₂O₇-V₂(VO)(P₂O₇)₂ on the surface of carbon fiber cloth.This material shows excellent electrochemical sodium storage performance.Carbon cloth is used as the base material.The matrix can better protect the nanostructure of Sn P₂O₇-V₂(VO)(P₂O₇)₂.Compared with the common r GO material,its initial capacity is greatly increased.The material is used as the anode material of the sodium ion battery.At a current density of 0.1 A g^-1,the initial capacity can reach 1600 m Ah g^-1.2.MXene is a two-dimensional inorganic compound with excellent performance.Compared with traditional batteries,MXene can provide more channels for ion movement and greatly increase the rate of ion transportation.In this work,the nano-sheet-like Sn P₂O₇/MXene composite material is synthesized through the low-temperature hydrothermal method.Compared with the accordion-like pure MXene material,this material has better sodium storage and higher initial capacity.This material displays high capacity and good stability,when it is used as the anode material of sodium ion batteries.At a current density of 0.1 A g^-1,the reversible specific capacity can be maintained at 240 m Ah g^-1 after 150 cycles.3.Carbon nanotubes(CNTs)are a class of carbon materials with excellent properties.The surface of CNTs is negatively charged or uncharged,so it is easy to combine with MXene materials.The combination of the two materials can play a synergistic effect,and the presence of CNT can inhibit the stacking of MXene.So the Sn-Sn P/MXene-CNT composite is synthesized with a simple self-assembly method,and this material is employed as the anode material of sodium ion battery.It has good cycle stability and rate performance.At a current density of 0.1 A g^-1,the reverle specific capacity of SIBs can be maintained at210 m Ah g^-1 after 130 cycles.