Synthesis of N‐Doped Graphene Photo‐Catalyst for Photo‐Assisted Charging of Li‐Ion Oxygen Battery

Abstract

Abstract In this work, nitrogen (N)‐doped graphene film is synthesized, as a photo‐catalyst, on one side of the copper foam by chemical vapor deposition and the copper foam is directly used as an electrode after porous Pd@rGO cathode loading to the other side of the foam for the photo‐assisted charging of the Li‐ion oxygen battery. The amount of urea (CO(NH2)2), which is used as N atom source, is optimized to get maximum photo‐anodic currents from the n‐type graphene films. The optical band gap and the valance band edge potential of the optimized N‐doped graphene film are determined as 2.00 eV and 3.71 VLi+/Li, respectively. X‐ray photoelectron spectra provided that the atomic percent of N atoms in the graphene film is 1.34% and the graphitic, pyrrolic and pyridinic N atom percentages are 54.01%, 42.20% and 3.79%, respectively. The photo‐assisted charging tests indicated that the N‐doped graphene film photo‐catalyst reduced the charging potential significantly even at 1000 mA g−1 (0.1 mA cm−2) current density and improved the cyclic discharge‐charge performance of the Li‐ion oxygen battery considerably.

Keywords

• chemical vapor deposition
• Li‐Ion oxygen batteries
• N‐doped graphene
• photo‐catalyst
• photo‐charging