Novel hollow Sn–Cu composite nanoparticles anodes for Li-ion batteries prepared by galvanic replacement reaction

摘要

Nanostructured hollow Sn–Cu multi-phase composite nanoparticles anode that contains Sn and Cu_6Sn_5 was synthesized via galvanic replacement reaction using Sn nanoparticles as a sacrificial template. The sacrificial oxidation of Sn and simultaneous reduction of Cu on the surface because of the redox potential difference is proposed to account for the formation of hollow Sn–Cu nanostructures. The structural evolution of the Sn–Cu hollow nanoparticle, in the process of galvanic replacement and structure, composition changes during charge/discharge processes were studied based on scanning electron microscope, X-ray powder diffraction, transmission electron microscopy, and energy dispersive Xray spectroscopy investigations. The electrochemical properties of the samples were evaluated by galvanostatic discharge– charge cycling, cyclic voltammetry, and electrochemical impedance spectroscopy. Compared with solid Sn–Cu nanoparticles, hollow Sn–Cu nanoparticles showed better capacity retention. The improved electrochemical performance may be attributed to the stable hollow structure and the combination of Cu_6Sn_5. The facile solution-based process and excellent cycling stability show great potential of the multi-phase Sn–Cu hollow composite nanoparticles as an anode material for lithium-ion batteries.