Binder-Free Flexible Three-Dimensional Porous Electrodes by Combining Microstructures and Catalysis to Enhance the Performance of Lithium-Oxygen Batteries

Metal-air batteries are promising for the next-generation energy storage because of attractive energy density, but they also face great challenges for applications. To intensify transfer and increase reaction active sites as well as decrease polarization, binder-free flexible three-dimensional porous oxygen electrodes were prepared by in situdeposition and decomposition of ZIF-67 on graphite foam (GF). Compared with GF, the modified sample has a much more stable discharge platform, lower charge/discharge polarization, higher reversibility, and higher reaction activity during oxygen reduction reaction and oxygen evolution reaction processes. The current densities of the reduction peak and oxidation peak of the pristine GF can be improved by a ZIF-67 derivative about 794 and 1367%, respectively. After 100 cycles at 0.1 mA·cm–2, the Rctof GF is decreased about 52% by the ZIF-67 derivative. The work paves a promising strategy for oxygen electrodes by combining absorption and electrocatalysis.