Revealing the aging process of solid electrolyte interphase on SiOx anode

作者：Guoyu Qian, Yi-Wei Li, Hai-Biao Chen, Lin Xie, Tongchao Liu, N. Yang, Yongli Song, Cong Lin, Jun-Fang Cheng, Naotoshi Nakashima, Meng Zhang, Zikun Li, Wen-Guang Zhao, Xiangjie Yang, Hai Lin, Xia Lu, Luyi Yang, Hong Li, Khalil Amine, Li-Quan Chen, Feng Pan · 发表于：Nature Communications · 年份：2023 · DOI：10.1038/s41467-023-41867-6 · 被引用次数：151 · 研究领域：Medicine

As one of the most promising alternatives to graphite negative electrodes, silicon oxide (SiOx) has been hindered by its fast capacity fading. Solid electrolyte interphase (SEI) aging on silicon SiOx has been recognized as the most critical yet least understood facet. Herein, leveraging 3D focused ion beam-scanning electron microscopy (FIB-SEM) tomographic imaging, we reveal an exceptionally characteristic SEI microstructure with an incompact inner region and a dense outer region, which overturns the prevailing belief that SEIs are homogeneous structure and reveals the SEI evolution process. Through combining nanoprobe and electron energy loss spectroscopy (EELS), it is also discovered that the electronic conductivity of thick SEI relies on the percolation network within composed of conductive agents (e.g., carbon black particles), which are embedded into the SEI upon its growth. Therefore, the free growth of SEI will gradually attenuate this electron percolation network, thereby causing capacity decay of SiOx. Based on these findings, a proof-of-concept strategy is adopted to mechanically restrict the SEI growth via applying a confining layer on top of the electrode. Through shedding light on the fundamental understanding of SEI aging for SiOx anodes, this work could potentially inspire viable improving strategies in the future.