Electrochemical behavior of Si nanoparticle anode coated with diamond-like carbon for lithium-ion battery

Diamond-like carbon (DLC) was coated on Si nanoparticle anodes using plasma-enhanced chemical vapor deposition (PECVD). The presence of DLC was confirmed by scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), energy-dispersive X-ray spectroscopy (EDX), electron probe microanalyzer (EPMA), Raman spectroscopy, and X-ray photoelectron (XPS) spectroscopy. Cells employing the coated anodes showed good cycling performance between 0 and 1.5 V, and a capacity of 1354 mAh g^-1 was retained after 100 cycles. A comparable cell employing a Si nanoparticle anode without the DLC coating quickly lost its capacity during cycling. The electrochemical properties of cells are characterized through impedance analysis, XPS, and SEM. It was observed that the coating improved ionic conductivity, and acted as a protective buffering layer on the Si nanoparticle electrode for lithium-ion batteries.