Nano Carbon-Based Hybrid Strategies for Mitigating Silicon Anode Expansion in Lithium-Ion Batteries: A Comprehensive Review.

Silicon is considered one of the most promising anode materials for lithium-ion batteries because of its high theoretical capacity and low lithiation potential. However, its practical application is limited by significant volume expansion, unstable solid-electrolyte interphase formation, and poor intrinsic conductivity. This review summarizes recent advances in hybrid strategies using multi-walled carbon nanotubes (MWCNTs), single-walled carbon nanotubes (SWCNTs), graphene, carbon nanofibers (CNFs), and pitch-derived carbons. We compare their respective benefits and drawbacks regarding conductivity, structural resilience, and scalability, while also addressing critical challenges such as dispersion, defect control, and processing costs. The discussion emphasizes the importance of hierarchical, multifunctional architectures that combine different forms of carbon to achieve synergistic performance. Finally, we outline future directions in interfacial engineering, defect and doping optimization, and electrode design under high-loading conditions. We believe that this review can offer perspectives on developing durable, energy-dense, and commercially viable silicon anodes for next-generation lithium-ion batteries.