Enabling the Transport Dynamics and Interfacial Stability of Porous Si Anode Via Rigid and Flexible Carbon Encapsulation for High‐Energy Lithium Storage

• Published in: Small (Weinheim an der Bergstrasse, Germany) Germany), 2024-12, Vol.20 (52), p.e2407560-n/a
• Main Authors: Cheng, Zhongling, Lin, Huanhao, Liu, Yueming, Li, Jihao, Jiang, Hao, Zhang, Haijiao
• Format: Article
• Language: English
• Subjects: Anodes; Carbon; Cycle ratio; Dopamine; Electrolytes; Encapsulation; hybrid carbon encapsulation; Interface stability; Ion storage; Ion transport; Liquid-solid interfaces; Lithium; Lithium-ion batteries; porous Si; Porous silicon; stable SEI film; stress‐buffering
• ISSN: 1613-6810; 1613-6829; 1613-6829
• DOI: 10.1002/smll.202407560

The stable electrode/electrolyte interface and fast electron/ion transport channel play important roles in boosting the rate performance and cycling life of lithium‐ion batteries. Herein, a porous silicon/carbon composite (pSi@PC@MC) is presented by integrating hollow porous silicon (pSi) with pitch‐derived carbon (PC) and dopamine‐derived mesoporous carbon (MC), employing microporous zeolite as the silicon source. The finite element simulation first reveals the stress release effect of rigid and flexible carbon encapsulation on the hollow Si anode for lithium‐ion storage. In situ and ex situ characterization results further elucidate that hybrid sp2/sp3 carbon coating greatly enhances the liquid/solid interface stability and the compatibility with the electrolyte, as well as facilitates the electron/ion transmission dynamics, achieving a uniform, stable, and LiF‐rich SEI film, ultimately improving the lithium storage performance. As expected, the as‐designed pSi@PC@MC anode delivers an impressive rate capability (756.6 mAh g−1 at 6 A g−1) and excellent cycling stability with a capacity of 1650 mAh g−1 after 300 cycles at 0.2 A g−1. Meanwhile, the pSi@PC@MC//NCM811 full‐cell exhibits an outstanding cycling stability (75.8% capacity retention after 100 cycles). This study highlights the significance of rational porous design and effective hybrid carbon encapsulation for the development of fast‐charging Si/carbon anodes. A hollow porous silicon/carbon composite with heterogeneous sp2/sp3 carbon coating is designed via finite element simulations. The rigid and flexible carbon encapsulation enhances the electron/ion transport kinetics and strengthens the interface stability. Meanwhile, hollow porous Si core further buffers the large volume expansion and stress release. As expected, the optimized anode shows an outstanding rate performance for lithium storage.