National Renewable Energy Laboratory , 15013 Denver West Parkway, Golden, Colorado 80401, Unites States.
Department of Chemical and Materials Engineering, University of Kentucky , Lexington, Kentucky 40506, United States.
ACS Appl Mater Interfaces. 2017 Nov 22;9(46):40143-40150. doi: 10.1021/acsami.7b08960. Epub 2017 Nov 7.
Polyvinylidene fluoride (PVDF) is the most popular binder in commercial lithium-ion batteries but is incompatible with a silicon (Si) anode because it fails to maintain the mechanical integrity of the Si electrode upon cycling. Herein, an alucone coating synthesized by molecular layer deposition has been applied on the laminated electrode fabricated with PVDF to systematically study the sole impact of the surface modification on the electrochemical and mechanical properties of the Si electrode, without the interference of other functional polymer binders. The enhanced mechanical properties of the coated electrodes, confirmed by mechanical characterization, can help accommodate the repeated volume fluctuations, preserve the electrode structure during electrochemical reactions, and thereby, leading to a remarkable improvement of the electrochemical performance. Owing to the alucone coating, the Si electrodes achieve highly reversible cycling performance with a specific capacity of 1490 mA h g (0.90 mA h cm) as compared to 550 mA h g (0.19 mA h cm) observed in the uncoated Si electrode. This research elucidates the important role of surface modification in stabilizing the cycling performance and enabling a high level of material utilization at high mass loading. It also provides insights for the future development of Si anodes.
聚偏二氟乙烯（PVDF）是商业锂离子电池中最常用的粘结剂，但与硅（Si）阳极不兼容，因为它在循环过程中无法保持 Si 电极的机械完整性。在此，通过分子层沉积合成了一种氧化铝酮涂层，并将其应用于由 PVDF 制成的层压电极上，系统地研究了表面改性对 Si 电极电化学和机械性能的单独影响，而不受其他功能性聚合物粘结剂的干扰。通过机械特性分析证实了涂层电极增强的机械性能，可以帮助适应反复的体积波动，在电化学反应过程中保持电极结构，从而显著改善电化学性能。由于氧化铝酮涂层的存在，Si 电极实现了高可逆循环性能，比未涂层 Si 电极的 550 mA h g（0.19 mA h cm）观察到的容量提高到 1490 mA h g（0.90 mA h cm）。这项研究阐明了表面改性在稳定循环性能和实现高负载量下高材料利用率方面的重要作用。它也为 Si 阳极的未来发展提供了思路。
