Dependence of structure of carbon nanowalls anode electrode on property of lithium-ion batteries

Lithium-ion (Li⁺) batteries have become indispensable to modern society. Currently, the anode made of graphite-based material is used in most of the Li⁺ batteries.

Carbon nanowalls (CNWs) are nanocarbon structures consisting of graphene sheets grown perpendicular to the substrate and have a high specific surface area. In this study, two CNWs with different structures were used to compare their performance as anode electrodes for Li⁺ batteries.

Two-type CNWs with different surface morphology were deposited by the inductively coupled plasma chemical vapor deposition (ICP-CVD) varying the Ar gas flow rate. A mixture gas of H2, CH4, and Ar was introduced into the chamber and used for CNW deposition with the ICP-CVD. The H2, and CH4 gas flow rates were fixed at 15 and 25 sccm and Ar gas flow rate was changed from 7 to 10 sccm.

The charge and discharge capacities of CNWs anode deposited at an Ar flow rate of 7 sccm in the 50th cycle were 47.8 and 35.7 mAh/g, respectively; those deposited at an Ar flow rate of 10 sccm were 46.7 and 30.0 mAh/g, respectively.From the results, there was no significant difference in both charge and discharge capacities. This suggests that differences in CNWs density do not have much effect on charge and discharge capacities per unit weight.