Xu Shu-Mao, Liang Xiao, Wu Xue-Yan, Zhao Shen-Long, Chen Jun, Wang Kai-Xue, Chen Jie-Sheng
Shanghai Electrochemical Energy Devices Research Center, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China.
Department of Bioengineering, University of California, Los Angeles, CA, 90095, USA.
Nat Commun. 2019 Dec 20;10(1):5810. doi: 10.1038/s41467-019-13712-2.
Inferior charge transport in insulating and bulk discharge products is one of the main factors resulting in poor cycling stability of lithium-oxygen batteries with high overpotential and large capacity decay. Here we report a two-step oxygen reduction approach by pre-depositing a potassium carbonate layer on the cathode surface in a potassium-oxygen battery to direct the growth of defective film-like discharge products in the successive cycling of lithium-oxygen batteries. The formation of defective film with improved charge transport and large contact area with a catalyst plays a critical role in the facile decomposition of discharge products and the sustained stability of the battery. Multistaged discharge constructing lithium peroxide-based heterostructure with band discontinuities and a relatively low lithium diffusion barrier may be responsible for the growth of defective film-like discharge products. This strategy offers a promising route for future development of cathode catalysts that can be used to extend the cycling life of lithium-oxygen batteries.
绝缘和块状放电产物中较差的电荷传输是导致锂氧电池循环稳定性差、过电位高和容量衰减大的主要因素之一。在此，我们报道了一种两步氧还原方法，即在钾氧电池的阴极表面预沉积一层碳酸钾层，以引导锂氧电池在连续循环中生长有缺陷的薄膜状放电产物。具有改善的电荷传输和与催化剂的大接触面积的缺陷膜的形成在放电产物的容易分解和电池的持续稳定性中起着关键作用。多级放电构建具有能带不连续性和相对较低锂扩散势垒的基于过氧化锂的异质结构可能是有缺陷的薄膜状放电产物生长的原因。该策略为未来阴极催化剂的开发提供了一条有前景的途径，可用于延长锂氧电池的循环寿命。
