Silicon–carbon composite anodes for lithium-ion batteries: synthesis, architecture, interfacial regulation, and practical prospects

Silicon–carbon composite anodes are among the most intensively studied candidates for next-generation lithium-ion batteries because they combine the high theoretical capacity of silicon with the conductivity, structural resilience, and processability of carbon. Yet the value of silicon–carbon design lies not simply in blending two materials. The most effective systems create a coordinated architecture in which carbon acts as an electron highway, a mechanical buffer, and an interfacial regulator, while silicon contributes most of the reversible capacity. Recent work has therefore shifted from simple physical mixing toward deliberate control of particle morphology, carbon deposition pathway, pore distribution, and secondary-particle assembly. This review revisits the field from that perspective. First, representative preparation routes are discussed, with emphasis on how ball milling, pyrolysis, chemical vapor deposition, spray drying, hydrothermal processing, and multistep integration shape the final electrode. Second, the structure–function relationship of core–shell, one-dimensional, layered, porous, and microspherical configurations is analyzed. Third, the review examines the electrochemical origins of capacity decay, rate limitation, and unstable interphases, then summarizes practical modification strategies including heteroatom doping, ternary hybridization, interface engineering, and electrolyte design. Finally, recent progress and remaining practical gaps are discussed, with particular attention to first-cycle lithium loss, electrode swelling, interphase stability, cost, and manufacturability. Rather than treating these issues as unsolved barriers, this review emphasizes how they have been progressively mitigated through carbon-network design, silicon–graphite hybridization, interface engineering, electrolyte regulation, and lithium-inventory management, while also highlighting the need for further validation under realistic full-cell and manufacturing conditions.