Preparation And Lithium Storage Performance Of Three-dimensional Porous Cu@SnO₂ Composite Electrode

With the advantages of high energy density,environmental friendliness and long cycle-life,lithium ion batteries?LIBs?are one of the most successful of energy storage devices.Now,the traditional commercial battery anode materials of graphite is difficult to meet the development of next-generation energy storage equipment.Sn O₂ has been considered to be a promising anode material,due to its relatively high theoretical capacity?1490 m Ah/g?,environmental benignity,low cost,high safety,ect.However,the problem of large volume and poor conductivity during the lithiation/delithiation process is a necessary factor limiting the application.Based on the principle of in-situ phase separation,a three-dimensional porous Cu@Sn O₂composites electrode was prepared by mechanical alloying,non-solvent phase separation?NIPS?and powder sintering.The porous structure is used to buffer the volume expansion of Sn O2,and improves the conductivity of the composite electrode.The research contents are as follows:?1?Cu₆Sn₅ alloy powder and copper powder were used as raw materials to prepare composite electrode precursor by NIPS method.Then,three-dimensional porous Cu@Sn O₂ composites electrode was prepared by oxidation-selective reduction and sintering process.Experimental results show that the composites electrode have the three dimensional continuous porous architecture,and Sn O₂ and Cu form a cluster structure and uniformly distributed in the three continuous network.The experimental results show that the composite electrode prepared under high temperature sintering at600°C exhibits good flexibility and lithium-ion storage performance.At a current density of 100 m A/g,the reversible specific capacity can reach up to 715 m Ah/g,and even after 50 cycles,it still maintains 433.9 m Ah/g,showing good cyclic stability.?2?A three-dimensional porous Cu@Sn O₂ composite electrode was prepared by preparing a high atomic ratio copper-tin alloy by high-energy ball milling.Experimental results show that the composite electrode has the three dimensional continuous hierarchical porous architecture.The secondary pores of the composite electrode after sintering at 300°C,proe size about 200 nm,and the ligament were about 400 nm.At a current density of 100 m A/g,the specific capacity is 1063.8m Ah/g,which decays to 149.5 m Ah/g after 100 cycles,but its specific capacity retention rate is 60%at a high current density of 1 A/g.In order to improve the electrochemical cycle stability of the composite electrode,the surface of the electroplating process was modified by PPY,and its electrochemical cycle performance maintained specific capacity at 605.6 m Ah/g after 100 cycles and increased by four times.