Graphene hybrid fiber supercapacitors: A review of fabrication methods, architectures, and performance enhancement strategies

In the rapidly evolving landscape of wearable electronics, hybridization strategies have emerged as fundamental design principles that synergistically combine complementary materials to overcome the inherent limitations of single-component systems. This review focuses on graphene hybrid fiber (GHF) supercapacitors, showing how rational hybridization mitigates π–π restacking in pristine graphene fibers, unlocking ion-accessible surface area, improving interfacial charge transfer, and maintaining mechanical compliance. We categorize four preparation routes—heteroatom doping, pre-spinning, post-spinning, and combined methodologies—and link them to three fiber architectures (layered, core–shell, and helical) that govern process–structure–property relationships. We critically examine synergistic interactions between graphene and four classes of functional components—heteroatom dopants, carbon nanomaterials, metal oxides/sulfides, and conductive polymers—to clarify mechanisms underpinning enhanced capacitance, rate capability, and durability under deformation. Key challenges are analyzed, including graphene sheet aggregation, interfacial compatibility, mechanical robustness in textile formats, voltage-window constraints, safety, and scalable, environmentally benign fabrication. We outline opportunities in interface engineering, hierarchical porosity control, standardized evaluation protocols for fiber devices, and in situ/operando diagnostics, alongside data-driven design to accelerate translation. By articulating an integrated materials–process–structure–performance framework, this review guides the design of next-generation GHF supercapacitors that leverage hybridization to deliver high energy/power density with long-term flexibility in wearable systems.