Sticky carbon coating enables high-area-capacity lithium storage of silicon-graphitic carbon hybrid

Pulverization and surface instability have been identified as the main impediments to the application of Si anodes in high-energy lithium-ion batteries (LIBs). In this study, a Si-graphitic carbon hybrid (SiG) is created via embedding Si nanoparticles in between expanding graphite interlayers, thus to be adopted as a model system to unravel structure-properties relations for LIBs applications. We explore the impact of artificial surface coating layers on the lithium cycling performance of SiG particles. In comparison with native SiG and carbon-coated SiG (CC-SiG), we find that the sticky-carbon coating, i.e., an epoxy-rich layer on top of the carbon coating, gave rise to superior cycle performance. In the sticky carbon coated SiG (SCC-SiG), the surface chemistry appears to have a pivotal role in both alleviating electrode disintegration and forming a favorable SEI rich in fluorine-polymers. These positive findings are examined in electrodes with mass loading ranging from 1.0 to 5.0 mg/cm(2), achieving area capacities up to similar to 5.0 mAh/cm(2). A full cell adopting >6 mg/cm(2) LiNi0.8Co0.1Mn0.1O2 (NCM811) cathode and SCC-SiG delivers stable cycling performances. It is hence unraveled that the carbon coating layer with reactive surface groups on the top is an unrecognized key for wide range of Si-based anodes. (C) 2021 Elsevier Ltd. All rights reserved.

Automated summary

This study investigates the impact of surface coating layers on the lithium cycling performance of Si-graphitic carbon hybrid particles. It is found that the sticky-carbon coating layer significantly improves the cycle performance by alleviating electrode disintegration and forming a favorable SEI rich in fluorine-polymers. These positive findings highlight the importance of carbon coating layers with reactive surface groups for a wide range of Si-based anodes.