Effect of Tungsten Nanolayer Coating on Si Electrode in Lithium-ion Battery.

Tungsten (W) was coated onto a silicon (Si) anode at the nanoscale via the physical vaporization deposition method (PVD) to enhance its electrochemical properties. The characteristics of the electrode were identified by scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray analysis, and electron probe X-ray microanalysis. With the electrochemical property analysis, the first charge capacities of the W-coated and uncoated electrode cells were 2558 mAh g and 1912 mAh g, respectively. By the 50th cycle, the capacity ratios were 61.1 and 25.5%, respectively. Morphology changes in the W-coated Si anode during cycling were observed using SEM and TEM, and electrochemical characteristics were examined through impedance analysis. Owing to its conductivity and mechanical properties from the atomic W layer coating through PVD, the electrode improved its cyclability and preserved its structure from volumetric demolition.