Redox polymer/cement electrolytes for structural supercapacitor with ultrahigh ionic conductivity and energy density

Structural supercapacitor (SSC) is a promising structural energy storage device that can be used as a component of buildings to maximize the utilization of building space while realizing energy storage. Currently, a major challenge for SSC is achieving ultrahigh ionic conductivity and energy density simultaneously, especially when the mechanical performance reaches an acceptable value. Herein, the redox polymer/cement electrolyte (RPCE) of A-Br-10 wt% and D-Br-0.3 M with remarkable ionic conductivity (68.88 and 70.97 mS/cm) and acceptable compressive strength (31.92 and11.04 MPa) are designed, aiming to boost the energy density of SSC by taking advantage of the redox characteristics of Br − . Notably, our fully SSCs with A-Br-10 wt% and D-Br-0.3 M as RPCE deliver a good energy density of 270.84 μWh/cm 2 at areal capacitance of 216.67 mF/cm 2 and an excellent energy density of 446.28 μWh/cm 2 at areal capacitance of 357.02 mF/cm 2 , respectively, while simultaneously maintaining a higher power density of 4500 Wh/cm 2 . These values are superior to the previous studies about all-solid-state SSCs, demonstrating their promising application potential in buildings.