Graphite Slurry Heat Treatment Temperature for Improving the Durability of CNWs Anode Materials of Lithium-Ion Batteries

Background Carbon nano wall (CNW) characterized by a large specific surface area were used, and graphite slurry was applied through a casting process to improve durability. Methods To improve adhesion between the current collector (copper foil) and CNWs, a titanium nitride (TiN) layer was deposited using the RF magnetron sputtering method. CNWs were then grown by injecting methane (CH 4 ) and hydrogen (H 2 ) using a microwave plasma enhanced chemical vapor deposition (PECVD) system. The casting process was performed by making the height of the graphite slurry uniform. Afterwards, heat treatment process was performed at 70℃, 75℃, and 80℃ on a hot plate to improve durability. Field emission scanning electron microscope (FE-SEM) and energy-dispersive X-ray spectroscopy (EDS) were used to confirm the presence of CNWs in the casting process. A Raman spectroscopy was used to analyze the structural properties of anode materials. The improvement in the durability of the anode material was confirmed by analyzing the electrochemical properties. Electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) were performed to characterize the lithium-ion battery. Results The cyclic voltammetry (CV) of the graphite slurry was measured at 20 cycles, which increased by about 8 cycles compared to other temperatures. As a result of electrochemical impedance spectroscopy, the R ct value was 25 Ohm at 75℃ heat treatment, which was about 4 times smaller than other temperatures.