Changing the carbon framework to produce low-expansion silicon-carbon composites for high-performance lithium-ion batteries

• • The Si/C composite achieves a specific capacity of 2179 mAh g–1 with an initial Coulombic efficiency (ICE) of 93.5% and a low specific surface area of 1.32 m2 g–1, enabling high energy density and reduced side reactions in full cells. • • A carbon framework with micropores of ~1.9 nm confines amorphous silicon, limiting volume expansion to 35.8% from delithiated to lithiated state, which is critical for electrode integrity and long-term cycling. • • Optimizing the median particle size (D50) to 8.2 μm yields a rate retention of 97.0% at 3 C relative to 0.1 C, demonstrating balanced ionic/electronic transport and mechanical robustness. • • In a practical 879 mAh pouch cell (graphite hybrid anode paired with NCM523), the material retains 87.46% capacity after 1000 cycles at 1 C, with a battery expansion rate below 8%, proving industrial viability.