Photoassisted Charging of Li-Ion Oxygen Batteries Using g-C(3)N(4)/rGO Nanocomposite Photocatalysts

[Image: see text] In this work, g-C(3)N(4)/rGO nanocomposites were synthesized to use them as photocatalysts in Li-ion oxygen batteries by aiming at the reduction of the charging potential efficiently under photoassisted conditions. Fourier transform infrared (FTIR) spectra showed that novel C=C bonds formed between g-C(3)N(4) and rGO during the decomposition of melamine and that the formation of these bonds was assumed to cause a red shift in the optical absorption band edge. The competition between the narrowing in the optical band gaps of the nanocomposites as a result of the red shift due to the presence of rGO and the degradation in the visible light utilization as a result of favorably absorbed incident light by rGO instead of g-C(3)N(4) pointed out that the g-C(3)N(4)/3% rGO nanocomposite has the optimum light absorbance efficiency. The photoassisted charging tests indicated that the g-C(3)N(4)/3% rGO nanocomposite reduced the charging potential effectively, especially at higher current densities, and improved the cyclic discharge–charge performance of the Li-ion oxygen batteries considerably.