Production of Sn–Cu/MWCNT composite electrodes for Li-ion batteries by using electroless tin coating

Abstract

Cycling stability of pure tin electrodes were aimed to improve by using a suitable combination of copper and multiwalled carbon nanotubes (MWCNTs). For this purpose, firstly Sn–Cu composite powders were produced using an electroless process. Then, Sn–Cu/MWCNT composite electrodes were prepared with dispersing different amounts of MWCNT (10wt.%, 20wt.%, 40wt.%) by high energy mechanical milling method. The surface morphology of the produced Sn–Cu/MWCNT composite powders was characterized using scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS) was used to determine the elemental surface composition of the composites. X-ray diffraction (XRD) analysis was performed to investigate the structure of the Sn–Cu/MWCNT composite powders. The electrochemical performance of Sn–Cu/MWCNT composite electrodes has been investigated by charge/discharge tests and cyclic voltammetry experiments. The cell discharge capacities were determined at a constant current in voltage range between 0.02V and 1.5V. AC Electrochemical Impedance Spectroscopy (EIS) analysis was also carried out to measure resistivity and Li-diffusion in the assembled cells. The amounts of MWCNTs were shown to be a crucial factor to improve Sn–Cu/MWCNT composite anodes for cyclability and reversible capacity.