Electrochemical Evaluation of Surface Modified Free-Standing CNT Electrode for Li-O2 Battery Cathode

In this study, carbon nanotubes (CNTs) were used as cathodes for lithium-oxygen (Li-O-2) batteries to confirm the effect of oxygen functional groups present on the CNT surface on Li-O-2 battery performance. A coating technology using atomic layer deposition was introduced to remove the oxygen functional groups present on the CNT surface, and ZnO without catalytic properties was adopted as a coating material to exclude the effect of catalytic reaction. An acid treatment process (H2SO4:HNO3 = 3:1) was conducted to increase the oxygen functional groups of the existing CNTs. Therefore, it was confirmed that ZnO@CNT with reduced oxygen functional groups lowered the charging overpotential by approximately 230 mV and increased the yield of Li2O2, a discharge product, by approximately 13%. Hence, we can conclude that the ZnO@CNT is suitable as a cathode material for Li-O-2 batteries.

Automated summary

In this study, the effect of oxygen functional groups on carbon nanotubes (CNTs) in Li-O-2 battery performance was confirmed by using CNTs as cathodes. By reducing the oxygen functional groups with ZnO coating, the overpotential during charging was decreased and the production of discharge product Li2O2 was increased. It was concluded that ZnO@CNT is a suitable cathode material for Li-O-2 batteries.