Effective Encapsulated Strategy throughout Lithiation/Delithiation: Enabling a Stable Interface and Fast Kinetics of Silicon Anode for High-Performance Lithium-Ion Half/Full Batteries

Abstract

Despite the ultrahigh theoretical capacity of silicon (Si), the large volume changes and low intrinsic electrical conductivity lead to inadequate cycle life and poor rate performance, hindering its commercial application. This work smartly used polydopamine-assisted deposition of SnO 2 on nano-Si in a hydrothermal environment, obtaining the nitrogendoped carbon (NC) and SnO 2 quantum dot hybrid-encapsulated Si@NC@ SnO 2 core−shell nanospheres. The core−shell Si@NC@SnO 2 demonstrated effective tolerance to the volume expansion of nano-Si due to the protective effect of the organic/inorganic hybrid shell, thereby maintaining its structural and interfacial stability. Furthermore, combined research from ex situ spectroscopy, physical fields, and DFT calculations reveals that the hybrid shell in the Si@NC@SnO 2 anode mainly turns into SnO and Li 2 O after lithiation, avoiding the failed encapsulated strategy caused by Sn coarsening during alloy-step SnO 2 reaction. The lithiated shell even stabilizes the electrode/electrolyte interface and facilitates charge carrier transport. Consequently, the Si@NC@SnO 2 anode exhibited a reversible capacity of 1056 mAh g −1 after 200 cycles at 0.3 A g −1 and a high rate capacity of 510.7 mAh g −1 at 2 A g −1 . Moreover, the full battery retained a capacity of 527.5 mAh g −1 after 100 cycles at 0.3 A g −1 . This work focused on an effective encapsulated strategy throughout the lithiation/delithiation processes and achieved a stable interface and excellent cycling performance of the Si anode, thereby providing insights for the commercialization of Si-based anodes in long-life lithium-ion batteries.

Binder-Free Intertwined Si and MnO2 Composite Electrode for High-Performance Li-Ion Battery Anode

“…Most existing efforts to address this problem focus on structure tuning, active/inactive composite design, and scale-down. Typically, engineering Si into various nanostructures, such as nanowires, − nanotubes, − core–shell, − hollow, , and yolk–shell structures, − alleviates the volume expansion and pulverization of Si upon cycling. However, the complex synthesis procedures and high costs pose scale-up concerns.…”