Study by a cycling voltammetry of carbon-based nanocomposites with Cu-Sn, Co-Sn, Ni-Sn nanoparticles for energy storage

摘要

Intermetallic Cu-Sn, Co-Sn, Ni-Sn nanoparticles have been synthesized through a template borohydride reduction using a carbon-containing support in a mixture of aqueous solutions of CuCl_2·2H_2O, CoCl_2·6H_2O, NiCl_2·6H_2O, and SnCl_2·2H_2O salts at the corresponding mass ratio Cu (Co, Ni):Sn. As a result carbon-based nanocomposites with intermetallic nanoparticles have been obtained. Carbon foam, carbon powder, and graphite have been used as supports. The morphology, structure, phase composition and surface element content of the prepared nanocomposites have been investigated by electron microscopy (SEM), energy dispersitive spectroscopy (EDS), and x-ray diffraction (XRD) analyses. The nanocomposite morphology is typical for the alloy materials. Cu_6Sn_5, CoSn_2 and Ni_3Sn_4 phases are formed according to the phase diagram of the binary Cu-Sn, Co-Sn, Ni-Sn systems. The surface element composition has proven the existence of the Cu, Co, Ni, and Sn. Electrochemical study of these nanocomposite materials has been carried out by cycling voltammetry. The charge-discharge tests have shown that these nanocomposite materials are characterized by a stable specific capacity after the 20 cycles, better cyclibility and higher efficiency compared to the Cu-Sn, Co-Sn, Ni-Sn alloy materials. Their 40% improved capacity makes them an alternative replacement of the graphite electrodes in Li-ion batteries.