Exploring pore solution chemistry and solid phase assemblies in cement-based electrolytes for potential structural batteries

This study develops a sustainable cement-based electrolyte for a cement-based battery by incorporating supplementary cementitious materials (SCMs) and epsom salt to enhance electrical performance. Ionic composition and liquid-phase characterization revealed that SCM and epsomite reduced [Ca²⁺] and [OH⁻] ion concentration while modulating [SO₄²⁻] concentration in the pore solution, depending on the SCM type. Silica fume-based mixes, with lower reactive alumina content, showed increased [SO₄²⁻] and higher ionic strength. The SF5E mix exhibited superior electrical performance, achieving a 56 % higher discharge life. Cyclic voltammetry indicated quasi-reversible behaviour with hybrid capacitive-faradaic characteristics, confirming its suitability for energy storage. The microstructural analysis highlighted the stable C–S–H formation, ensuring mechanical integrity alongside electrical functionality. The findings establish SF5E as the optimal electrolyte, demonstrating a balance between ionic conductivity and structural stability. By linking cement chemistry with battery performance, this work lays the foundation for a scalable, self-sustaining energy storage system for applications in structural health monitoring.