posted on 2024-01-08, 19:04authored byOrynbassar Mukhan, Ji-Su Yun, Hirokazu Munakata, Kiyoshi Kanamura, Sung-Soo Kim
The effect of carbon coating on the interfacial charge
transfer
resistance of natural graphite (NG) was investigated by a single-particle
measurement. The microscale carbon-coated natural graphite (NG@C)
particles were synthesized by the simple wet-chemical mixing method
using a phenolic resin as the carbon source. The electrochemical test
results of NG@C using the conventional composite electrodes demonstrated
desirable rate capability, cycle stability, and enhanced kinetic property.
Moreover, the improvements in the composite electrodes were confirmed
with the electrochemical parameters (i.e., charge transfer resistance,
exchange current density, and solid phase diffusion coefficient) analyzed
by a single-particle measurement. The surface carbon coating on the
NG particles reduced the interfacial charge transfer resistance (Rct) and increased the exchange current density
(i0). The Rct decreased from 81–101 (NG) to 49–67 Ω cm2 (NG@C), while i0 increased from
0.25–0.32 (NG) to 0.38–0.52 mA cm–2 (NG@C) after the coating process. The results suggested both electrochemically
and quantitatively that the outer uniformly coated surface carbon
layer on the graphite particles can improve the solid–liquid
interface and other kinetic parameters, therefore enhancing the rate
capabilities to obtain the high-power anode materials.