Highly Stabilized Silicon Nanoparticles for Lithium Storage via Hierarchical Carbon Architecture

To address the huge volume expansion and the severe side reactions on silicon (Si) as an anode for lithium storage, we propose a hierarchical carbon architecture to composite with Si nanoparticles. This architecture is composed of an outer carbon shell, N-doped carbon nanotubes (CNTs), and inner carbon coating, which originated from the Co-zeolitic imidazole framework (ZIF-67) and polydopamine (PDA). The cycling stability and rate capability of the Si anode for lithium storage have significantly improved because of the unique carbon architecture. Insitu transmission electron microscopy (TEM) and other physical characterization methods confirm that Si nanoparticles are highly stabilized concurrently by the outer carbon shell that buffers the volume change of Si and the inner carbon coating that prevents the Si from direct contact with the electrolyte, leading to the improved cycling stability of Si. Additionally, all of the carbon textures, i.e., N-doped CNTs, the outer carbon shell, and inner carbon coating, provide an excellent electronically conductive network, which endows the Si anode with excellent rate capability. This carbon architecture provides a promising solution to the issues present in the Si anode for its use in high energy lithium-ion batteries.