Kosin Marvin, Dondrup Simon, Girschik Jan, Burfeind Jens, Apfel Ulf-Peter, Grevé Anna
Fraunhofer Institute for Environmental Safety and Energy Technology UMSICHT Osterfelder Str. 3 46047 Oberhausen Germany.
Inorganic Chemistry I Faculty of Chemistry and Biochemistry Ruhr University Bochum Universitätsstr.150 44801 Bochum Germany.
Glob Chall. 2023 Apr 7;7(6):2200223. doi: 10.1002/gch2.202200223. eCollection 2023 Jun.
Compared to other battery technologies, metal-air batteries offer high specific capacities because the active material at the cathode side is supplied by ambient atmosphere. To secure and further extend this advantage, the development of highly active and stable bifunctional air electrodes is currently the main challenge that needs to be resolved. Herein, a highly active carbon-, cobalt-, and noble-metal-free MnO/NiO-based bifunctional air electrode is presented for metal-air batteries in alkaline electrolytes. Notably, while electrodes without MnO reveal stable current densities over 100 cyclic voltammetry cycles, MnO containing samples show a superior initial activity and an elevated open circuit potential. Along this line, the partial substitution of MnO by NiO drastically increases the cycling stability of the electrode. X-ray diffractograms, scanning electron microscopy images, and energy-dispersive X-ray spectra are obtained before and after cycling to investigate structural changes of the hot-pressed electrodes. XRD results suggest that MnO is dissolved or transformed into an amorphous phase during cycling. Furthermore, SEM micrographs show that the porous structure of a MnO and NiO containing electrode is not maintained during cycling.
与其他电池技术相比，金属空气电池具有较高的比容量，因为其阴极侧的活性材料由周围大气提供。为了确保并进一步扩大这一优势，目前需要解决的主要挑战是开发高活性和稳定的双功能空气电极。在此，我们展示了一种用于碱性电解质中金属空气电池的高活性、无碳、无钴和无贵金属的MnO/NiO基双功能空气电极。值得注意的是，不含MnO的电极在100次循环伏安循环中显示出稳定的电流密度，而含MnO的样品则表现出优异的初始活性和升高的开路电位。沿着这条线，用NiO部分替代MnO极大地提高了电极的循环稳定性。在循环前后获得X射线衍射图、扫描电子显微镜图像和能量色散X射线光谱，以研究热压电极的结构变化。XRD结果表明，MnO在循环过程中溶解或转变为非晶相。此外，SEM显微照片显示，含MnO和NiO的电极的多孔结构在循环过程中没有保持。
