Ceramic Fiber-Regulated Cement-Based Structural Supercapacitors with Enhanced Ion Transport and Multifunctional Performance

With the increasing demand for low-carbon and integrated energy-storage systems, cement-based structural supercapacitors (CSSCs) have attracted growing attention because they combine energy-storage capability with structural load-bearing functions. However, limited ion transport within the cement matrix remains a key challenge. In this study, ceramic fibers were incorporated into a LiOTf/PAA-containing cement-based electrolyte to regulate ion transport while maintaining mechanical performance. Fiber−matrix interfacial regions formed during hydration provide additional electrolyte-containing transport pathways, while well-dispersed fibers help connect spatially separated transport regions and facilitate ion migration. At a ceramic fiber content of 0.8 wt %, the cement-based electrolyte exhibits the highest ionic conductivity of 2.62 mS cm−1. The corresponding CSSC delivers an areal capacitance of 834.67 mF cm−2, representing a 151.9% increase over the fiber-free system, and a maximum areal energy density of 260.83 μ Wh cm−2. Meanwhile, compressive and flexural strengths of 20.37 and 5.04 MPa are retained, respectively. Under compressive loading, the assembled device maintains stable charge−discharge behavior and retains 92.3% of its initial areal capacitance at an applied load of 4 kg. These results indicate that appropriate ceramic-fiber incorporation can improve ion transport and energy-storage performance while preserving mechanical functionality, supporting the potential of this strategy for integrated structural energy-storage applications.