| 초록 |
Graphite is typically used as LIB anode due to its high capacity, stability and low cost but its structure is easily destroyed at high C-rate. To enhance rate capability, we introduce ionic C-F bond on graphite surface . Amount of introduced ionic C-F bond on graphite surface can be controlled by partial pressure of F2 gas. There are no large structural changes after fluorination. To evaluate charge/discharge capacity and high-rate capability of the modified graphite, lithium ion coin half cell was fabricated by using prepared graphite and Li metal as anode and cathode, respectively. The capacity of the pristine and modified graphite is measured at 0.2 C and they are not significantly different. However, the modified graphite has higher capacity than pristine graphite at high C-rate. It is attributed that diffusivity of lithium ion and charge transfer properties are improved by introduced ionic C-F bond due to its high electronegativity. |
