Closed Pores as Internal Stress‐Regulation Units for Practical Silicon–Carbon Anodes

ABSTRACT Silicon–carbon anodes are among the most promising candidates for high‐energy lithium‐ion batteries, yet their practical implementation remains constrained by lithiation‐induced outward deformation, electrode cracking, and persistent interphase degradation. Here, closed pores are introduced as internal stress‐regulation units to address the coupled mechanical and electrochemical instability of silicon–carbon anodes. Heteroatom‐doped carbon hosts are engineered to contain abundant closed nanopores, which redirect expansion‐induced stress toward the particle interior and suppress macroscopic electrode swelling. Meanwhile, heteroatom doping enlarges the carbon interlayer spacing and enhances electronic conductivity, enabling accelerated and more balanced Li + insertion/extraction kinetics. As a representative material, the nitrogen–doped silicon–carbon composite delivers a reversible capacity of 1756.5 mAh g − 1 , an initial Coulombic efficiency of 90.2%, and 868.4 mAh g −1 at 3 C, while reducing electrode thickness expansion from 38.4% to 13.1% after 50 cycles. The material is further produced in 6 kg batches and enables 2 Ah LiNi 0.8 Co 0.1 Mn 0.1 O 2 (NCM811) pouch cells with 80.0% capacity retention after 1200 cycles and only 8.4% thickness growth after 900 cycles. Machine–learning–guided phosphorus doping further validates the transferability of the closed‐pore design. This work establishes closed‐pore stress regulation as a scalable structural strategy for practical low‐expansion silicon–carbon anodes.