A flexible cement-based supercapacitor with engineered pore structure for integrated multifunctional energy storage

Tailored pore network FPCE was designed as the electrolyte for FCS. • Cement-PA-KOH-AM20 integrates good electrochemical performance with outstanding mechanical flexibility. • Operates reliably at −10-65 °C, resists damage, provides 7 °C insulation, and retains performance after 6 months outdoors. • Powers LEDs, phones, displays, and fans even under bending or twisting. Cement-based supercapacitors are emerging as key enablers of the green transition, unifying the widespread infrastructural presence of cement with the ability to store electrical energy. However, their inherent rigidity has hindered integration into irregular, free-form architectural surfaces. Here, we report the first flexible cement-based supercapacitor, which combines high electrochemical performance with exceptional mechanical adaptability. The device employs a cement-composite electrolyte engineered with a tailored network of mesopores and capillary pores, achieving an ionic conductivity of 35.28 mS cm −1 alongside a low Young's modulus of 81.6 MPa. In an asymmetric electrode configuration, the supercapacitor delivers an areal capacitance of 215.3 mF cm −2 , an energy density of 76.55 μWh cm −2 , and a power density of 726.95 μW cm −2 , with 83.3% capacitance retention over 2000 cycles. It operates reliably from −10 to 65 °C, withstands mechanical damage without failure, provides a 7 °C thermal insulation benefit, and shows negligible performance loss after six months outdoors. Capable of efficient solar energy storage, it can power small electronic devices such as LEDs, a mobile phone, and fans even when bent or twisted. This work demonstrates a versatile, deformable energy-storing cement, paving the way for multi-function building materials in next-generation free-form architecture.