Bridging conductivity and stability: challenges and progress in organic ionic-electronic conductors for overcoming Si anodes degradation in high-energy lithium-ion batteries

Organic mixed ionic/electronic conductors (OMIECs) have emerged as transformative materials to address the critical challenges of silicon (Si) anodes in high-energy lithium-ion batteries (LIBs). Despite Si’s ultrahigh theoretical capacity (4200 mAh g⁻¹), its practical application is hindered by severe volume expansion (>300 %), unstable solid electrolyte interphase (SEI), and poor intrinsic conductivity, leading to rapid capacity decay and mechanical degradation. This review systematically explores the dual roles of OMIECs as multifunctional binders and protective coatings, leveraging their unique synergy of ionic/electronic conductivity, mechanical elasticity, and interfacial adaptability. As binders, OMIECs establish robust 3D conductive networks to enhance charge transfer kinetics, accommodate volume fluctuations through dynamic covalent/noncovalent interactions, and stabilize electrode integrity via strong adhesion. As coatings, they suppress electrolyte decomposition, regulate homogeneous Li⁺ flux to inhibit dendrite growth, and form hierarchical ion/electron transport pathways to minimize polarization. The review categorizes OMIECs into heterogeneous blends, block copolymers, and homogeneous single-component systems, elucidating their structure–property-performance relationships in Si anodes. Key challenges are critically analyzed, including the doping instability and mechanical brittleness of n-type OMIECs under reducing potentials, as well as air-sensitive doped states complicating characterization. Future research should focus on a comprehensive approach spanning molecular architecture design, aggregation state modulation, morphology design and electrolyte compatibility optimization to stabilize doping performance and enhance mechanical resilience through innovative crosslinking strategies. Additionally, the development of advanced in situ characterization techniques and computational simulation techniques will be crucial for gaining deeper insights into the dynamic behavior of OMIECs during operation. By bridging fundamental material design with practical application insights, this review highlights the transformative potential of OMIECs in advancing next-generation LIBs, offering a roadmap for overcoming Si anode limitations and achieving high-energy–density, long-cycle-life energy storage systems.