Ion-compensation driven optimizing electrode/electrolyte interface in cementitious electrolytes for high-performance structural supercapacitors

Journal article, 2026

Cement-type supercapacitors (CTSs), as groundbreaking advancement in construction materials, face critical limitations in reconciling structural robustness with high ionic conductivity and capacitive performance. In this study, a polymer-modified cementitious electrolyte was developed by integrating polycarboxylate/acrylic acid copolymer/sodium polyacrylate (PC/PAA/PAANa) network. The tripartite optimization mechanism operates synergistically: (1) Ion compensation through -COO- and Na+ dynamic coordination balances cation/anion migration, (2) Concentration-gradient driven transport, and (3) Porosity modulation creates hierarchical channels enabling low-tortuosity ion percolation. Coupled with rhomboid flower-like clusters rGO/Bi2O3 cathode exhibiting ultrahigh areal capacity of 0.593 mAh cm−2, displaying acceptable capacity retention of 40.1% after 300 charging discharging cycles. The optimized CTS with PC/PAA/PAANa-based cementitious composite achieves a high ionic conductivity (30.56 mS cm−1) with mechanical durability (compressive strength ∼15 MPa). The CTS exhibits significant specific capacitance of 422.4 F g−1 and impressive energy density of 132 Wh kg−1 (69.4 μWh cm−2) at a power density of 493.4 W kg−1 (262.2 μW cm−2). This polymer-modified cement electrolyte design provides a materials pathway for developing high-performance energy-storing concrete structure.