A large areal capacitance structural supercapacitor with a 3D rGO@MnO foam electrode and polyacrylic acid-Portland cement-KOH electrolyte

Recently, structural supercapacitors have attracted considerable attention due to their concurrent capability to store electrochemical energy and support mechanical loads. However, the greatest challenge in realizing an integrated electro-mechanical system is the development of highly compatible electrodes and structural electrolytes with superior mechanical and electrochemical performance. Here, a structural supercapacitor assembled with a 3D rGO@MnO 2 nickel foam electrode and polyacrylic acid-Portland cement-KOH electrolyte is reported to solve the challenge for the first time. The resulting rGO@MnO 2 electrode exhibits a high areal capacitance of 1.84 F cm −2 at 0.5 mA cm −2 , with the areal capacitance remaining at 1.13 F cm −2 even at a current density of 40 mA cm −2 . The structural electrolyte with 6 wt% polyacrylic acid-Portland cement-KOH shows the best combination of an ionic conductivity of 2.13 mS cm −1 and a compressive strength of 28.5 MPa. The resulting asymmetric structural supercapacitor with an areal capacitance of 51.5 mF cm −2 at 0.1 mA cm −2 is superior to those reported in latest studies based on carbon materials and resin, which suggests its potential application in structural energy storage for civil engineering. The fabrication process of an asymmetric structural supercapacitor (SSC) with structural electrodes and structural electrolytes.