3D-Printed Concrete Structural Supercapacitor with PVA-KOH Enhanced Polymer Mortar Electrolyte (2026-03)¶

Integrating energy storage functionality into structural building elements provides a new paradigm for future buildings to serve as large-scale energy storage. This study developed a new printable cement-based solid electrolyte, composed of polyvinyl alcohol-potassium hydroxide (PVA-KOH), enabling the digital fabrication of building-integrated energy storage components. The developed mortar exhibits favorable printability, enabling layer-by-layer deposition and simultaneous integration of pre-treated carbon black-coated nickel foam electrodes. The integrated printing process not only facilitates the construction of complex geometries but also enhances mechanical interlocking and interfacial bonding, leading to improved structural performance. The mechanical properties, energy storage capability, and microstructural characteristics of the structural supercapacitor were tested. Compared to pure mortar specimens (without electrode), the 3D-printed supercapacitor achieved a compressive strength of 30.68 MPa (a 20% increase) and a flexural strength of 13.37 MPa (a 28.6% increase). The substantial enhancement in flexural performance is primarily attributed to the incorporation of electrodes, which simultaneously enhanced ductility by up to 160.5%. Electrochemically, the device delivers an areal capacitance of 46.95 mF/cm2 and an ionic conductivity of 1.65 mS/cm. Microstructural and chemical analyses confirm strong electrode–electrolyte adhesion and the synergistic role of PVA-KOH in modifying hydration products. This work demonstrates the potential of integrating 3D printing technology with functional polymer-modified cementitious materials to realize structural supercapacitors with balanced mechanical and electrochemical performance.