| The theoretical specific capacity of tin-based metal anode materials is 992 m Ah·g-1,and its cycle capacity is better than that of pure tin anode.Tin-based metal anode is one of the hotspots in the research of next-generation lithium-ion battery anode materials.However,the tin-base alloy materials prepared by the traditional process are easy to fall off from the collector,which leads to the poor cycling performance of the tin-base alloy electrode materials.In this paper,tin-based alloy thin film material was prepared by layered deposition of Sn and Ni/Co/Fe on copper foil and subsequent heat treatment,its structure characterization and properties were tested.The main research contents are as follows:（1）With copper foil as the substrate,Sn and Ni are deposited layer by layer,and the alloy thin film material is obtained after subsequent heat treatment.Through the study of dc voltage size,the ratio of time on Sn and Ni,the total time,annealing temperature,holding time.The best deposition conditions and heat treatment conditions are obtained.The best voltage size is 3 V,the ratio of time on Sn and Ni are 30 s and 10 s,the total time is 5 min,heat treatment condition is 400℃and 8 h.The Sn-based alloy film prepared under this condition has a fine grain structure,excellent cycle and rate performance.（2）The electrochemically excellent Sn-Co-Cu alloy thin films were obtained by using copper foil as substrate,the deposition time of Sn layer and Co layer was 30 s and 10 s,the deposition time was 5 min,and the deposition voltage was 3 V.When the current density is 2 000 m A·g-1,the specific charge and discharge capacities of 1 000 cycles are264.6 and 265.4 m Ah·g-1,the coulomb efficiency is 99.6%.In the rate performance test,the discharge specific capacities of 1 C,2 C,5 C,10 C,20 C,1 C and 20C(1 C=100m A·g-1,0～3 V)are 1 561.5,1 091.1,969.7,814.7,730.9,1 395.9 and 720 m Ah·g-1,respectively,showing good rate performance.（3）Sn-Fe alloy films with excellent electrochemical properties were prepared under the conditions of copper foil as substrate,Sn layer deposition time of 30 s and Fe layer deposition time of 10 s,total deposition time of 5 min,deposition voltage of 3 V,heat treatment temperature of 400℃and holding 8 h.When the current density is 2 000 m A·g-1,the specific charge-discharge capacities of 1 000 cycles are 641.9 and 646.2 m Ah·g-1,respectively,and the coulomb efficiency is 99.3%.In the rate performance test,at the current density of 1 C,2 C,5 C,10 C,20 C,1 C and 20 C(1 C=100 m A·g-1,0～3V),the discharge specific capacities are 862.9,752.6,642.6,599.7,515.7,908.3 and 550 m Ah·g-1,respectively.Tin-based film anode materials with good crystal morphology were prepared by electrodeposition and subsequent heat treatment.The electrochemical properties of tin-based films used as anode materials for lithium-ion batteries were discussed.The reaction mechanism of alloying/dealloying is described in detail,which provides an effective method for improving the electrochemical performance of lithium-ion batteries. |
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