The Preparation And Performance Research Of The Hollow Tin-Nickel Alloy@PEO As Anode For Lithium Ion Batteries

The urgent need for the development of an new generation of high-performancelithium-ion batteries is searching for novel anode materials for lithium-ion batterieswith high capacity. However, a great deal of negative-electrode materials with highcapacity,such as Si-based, Sn-based, Ge-based and graphite,suffer from seriousvolume expansion and generate mechanical stress during the alloying/dealloyingprocess,which leads to the pulverization of the active materials and thus the poorelectrochemical performance.Three-dimensional Sn-Ni alloy is of great significance for the development ofhigh-capacity and high-power lithium-ion battery. However, the application is limitedby the poor stability of3D nanostructure and large volume change during the alloyingprocess. In this paper, we designed and prepared Sn-Ni alloy hollow nanoparticles(Sn-Ni alloy HNPs) and Sn-Ni alloy nanotubes (Sn-Ni alloy NTs) as anodes forlithium-ion batteries by galvanic replacement reaction and coating polymer membrane.Scanning electron microscope (SEM), Transmission electron microscopy (TEM) andX-ray diffraction (XRD) were used to measure the morphology, structure andcomposition of the samples,and then confirm the formation of hollow structure andthe successful coating of polymer. In contrast with bare Sn-Ni alloy HNPs, PEOcoated Sn-Ni alloy HNPs （Sn-Ni alloy@PEO membrane HNPs） exhibits betterelectrochemical performance, with a capacity of506.6mAhg-1over50cycles, butwithout coating of the Sn-Ni alloy HNPs capacity only300mAhg-1, about improved200mAhg-1; Compared with Sn-Ni alloy NTs without coating, Sn-Ni alloy@PEOmembrane NTs shows better electrochemical characteritics, maintaining a capacity of0.88mAhcm-2over200cycles, without coating Sn-Ni alloy NTs only0.6mAhcm-2,improved0.28mAhcm-2. Its good electrochemical performance is due to the hollownanostructure and flexible polymer shells which relieves the volume change duringthe charging and discharging process and can also help in preventing the pulverizationof the three dimensional nanostructure arrays electrode caused by the deformation; atthe same time, PEO polymer film avoids the direct contact of the electrolyte and theelectrode effectively. so it plays a role of separator, and the complex of PEO withalkali metal salts have ion conductivity, be beneficial to lithiumion transport.