Zheng Lituo, Li Lingjun, Shunmugasundaram Ramesh, Obrovac M N
Department of Chemistry , Dalhousie University, Halifax , Nova Scotia B3H 4R2 , Canada.
College of Materials Science and Engineering , Changsha University of Science and Technology , Changsha 410004 , P. R. China.
ACS Appl Mater Interfaces. 2018 Nov 7;10(44):38246-38254. doi: 10.1021/acsami.8b14209. Epub 2018 Oct 24.
NaNiMnO is a promising sodium-ion battery cathode material that has been extensively studied. However, the air sensitivity of this material limits practical application and is not well understood. Here, we present a detailed study of NaNiMnO powders stored in different atmospheres (oxygen, argon, and carbon dioxide), either dry or wet. X-ray diffraction and Fourier transform infrared measurements were used to characterize the materials and their surface species before and after controlled-atmosphere storage. It was determined that the exposure of untreated NaNiMnO powders to moisture results in desodiation and material degradation, leading to poor cycling. This effect was found to be caused by reactive surface species. From these results, a simple ethanol washing method was found to significantly reduce the air-reactivity and improve the electrochemical performance of NaNiMnO by removing surface impurities formed by air exposure.
NaNiMnO是一种很有前景的钠离子电池正极材料，已得到广泛研究。然而，这种材料对空气的敏感性限制了其实际应用，且人们对此尚未完全了解。在此，我们对存储在不同气氛（氧气、氩气和二氧化碳）中、干燥或潮湿环境下的NaNiMnO粉末进行了详细研究。利用X射线衍射和傅里叶变换红外测量来表征在可控气氛存储前后的材料及其表面物种。结果表明，未经处理的NaNiMnO粉末暴露于湿气中会导致脱钠和材料降解，从而导致循环性能不佳。发现这种效应是由活性表面物种引起的。基于这些结果，发现一种简单的乙醇洗涤方法可通过去除因空气暴露而形成的表面杂质，显著降低NaNiMnO的空气反应性并改善其电化学性能。
