In situ visualizing the interplay between the separator and potassium dendrite growth by synchrotron X-ray tomography. (May 2021)

• Record Type: Journal Article
• Authors: Ni, Ling; Osenberg, Markus; Liu, Haijun; Hilger, André; Chen, Libao; Zhou, Dong; Dong, Kang; Arlt, Tobias; Yao, Xiayin; Wang, Xiaogang; Chen, Yanan; Li, Yutao; Zhao, Kangning; Yang, Chao; Manke, Ingo; Sun, Fu; Chen, Renjie
• Is Part Of: Nano energy. Volume 83(2021)
• Publication Date: 2021-05
• Subjects: Potassium metal anode -- Synchrotron X-ray Tomography -- High mechanical separator -- Bulky potassium deposition; Nanoscience -- Periodicals; Nanotechnology -- Periodicals; Nanostructured materials -- Periodicals; Power resources -- Technological innovations -- Periodicals; Nanoscience; Nanostructured materials; Nanotechnology; Power resources -- Technological innovations; Periodicals; 621.042
• DOI: 10.1016/j.nanoen.2021.105841
• Languages: English
• ISSNs: 2211-2855

Abstract

Abstract: Rechargeable potassium (K) batteries are a promising next-generation technology for low-cost grid scale energy storage applications. Nevertheless, the undesirable interfacial instabilities originating from the interplay between the employed separators and electrodes largely compromise the battery's performance, and the underlying mechanism of which remains elusive. Herein, the interfacial stability between three types of commercial separators (Celgard 2325, Celgard 2400 and GF/D) and the K electrodeposits is investigated in K|K symmetric cells via in-situ Synchrotron X-ray tomography technique. It is demonstrated that the cell built with a Celgard 2400 separator can achieve a stable cycling performance due to its high mechanical strength and integrity along the thickness direction, thus alleviating the K dendrites growth. In contrast, a GF/D membrane of low mechanical cohesion and excessive porosity is found to be easily deformed and filled with deciduous potassium dendritic aggregates during battery cycling. Similarly, the tri-layer Celgard 2325 separators, which are weakly bonded by interlaminar forces, are found to be severely delaminated by the overgrowth of K dendrites. Furthermore, it is revealed that the delamination failure behaviors of Celgard 2325 is driven by the local stress induced by the spatially and heterogeneously formed "dead" K dendrites. Our work provides direct visualization of morphological evolvement of the separators in presence of potassium dendrites in K|K symmetric cells and highlights the significance of mechanical cohesion, porosity distribution and mechanical integrity of separators in dictating the battery's performance under realistic battery operation conditions. As a result, these discoveries provide an in-depth understanding that is needed to design next-generation high performance separators to mitigate the formation of potassium dendrite in KMBs. Graphical Abstract: ga1 Highlights: Synchrotron X-ray tomography and SEM are jointly used to reveal the interplay between K electrodeposits and separators. It is found that the tri-layer Celgard 2325 can be evasively penetrated by the dendritic type K electrodeposits. The GF/D separator is found be filled/accumulated with a large amount of K electrodeposits. It is revealed that the Celgard 2400 separators could maintain their structural integrity and suppress K dendrites.