Electrochemical Synthesis And Properties Research Of Tin Based Alloy Film Anode For Lithium-ion Batteries

Tin based anode materials have been considered to be one of the most promisingalternative anode materials for lithium-ion batteries with high theoretical specificcapacity (994mAh g-1)、low cost and enhanced safety. However, the large volumechange with the resulting pulverization of the active alloy particles and poor cyclestability during the charge-discharge processes are still challenged to practical use. Inthis paper，The tin based alloy films anode were prepared by electrochemicalcodeposition which is simple, economic, and controllable. Comprehensive utilizationthe advantages of the active/inactive composite alloy system and thin film improvedthe properties of tin based materials. A series of characterization methods andelectrochemical tests were used to study the morphologies and electrochemicalperformance of alloy films.Firstly, Sn-Co alloy film-anode materials were prepared by electrochemicalcodeposition, and the effects of copper substrate, deposition current density, thethickness of alloy film on the properties of materials were studied, respectively. Theresults reveal that the Sn-Co alloy films (Sn/Co=76.31:23.69, mole ratio) with thethickness of0.8μm electro-deposited under the current density of15mA cm-2on thenodule-type Cu foil show the best electrochemical performance due to the finestparticle size, optimized Co content and thickness. The initial discharge specificcapacity and colombic efficiency are949.3mAh g-1and90.5%, respectively. Thedischarge specific capacity remains735.8mAh g-1afer40cycles. Moreover, thecycling stabilities are outstanding and colombic efficiency more than96%, under therate of0.1C,0.4C,1C and2C.Secondly, Sn-Ni alloy film-anode materials were prepared by electrochemicalcodeposition, and effects of copper substrate, deposition current density, the thicknessof alloy film and the amount of additives on the properties of materials were discussed,respectively. The results reveal that the Sn-Ni alloy films (Ni3Sn4) with the thicknessof0.9μm electro-deposited under the current density of20mA cm-2on thenodule-type Cu foil show the best electrochemical performance. The initial dischargespecific capacity and coulombic efficiency are611.5mAh g-1、96.2%, respectively.The discharge specific capacity remains506.3mAh g-1afer40cycles.At last, Sn-Co-Zn composite alloy film anodes were synthesized byelectrochemical codeposition. XRD analysis shows that the Zn exists in the Sn-Co-Zn composite alloy in the form of element. The composite alloy film, electro-depositedunder the current density of10mA cm-2, present porous structure and showoutstanding electrochemical performance. The initial discharge specific capacity is951.6mAh g-1, and857.9mAh g-1after40cycles.