In-situ polymerized polyacrylamide/magnesium phosphate cement electrolyte for structural supercapacitor

Organic/inorganic composite electrolytes can effectively avoid contradictory relationship between ionic conductivity and mechanical properties as well as poor interfacial contact of electrode/solid electrolyte. However, direct mixing of organic/inorganic materials leads to low dosage and poor dispersion of polymers owing to macromolecular chains. Herein, we firstly prepare polyacrylamide/magnesium phosphate cement (PAM/MPC) electrolytes via in-situ polymerization during cement hydration. The weight average molecular weight of polymerized PAM in MPC paste is around 1500 with high concentrated degree of molecular weight distribution. As the dosage of acrylamide (AM) increases to 40 %, polymerized PAM completely interpenetrates into MPC matrix. The composite electrolyte possesses the optimum multifunctionality with ionic conductivity of 54 mS cm −1 and compressive strength of 30.2 MPa, corresponding structural supercapacitor (SSC) can obtain high specific capacitance of 32.0 F g −1 and energy density of 4.4 Wh kg −1 . With the lowest equivalent series resistance, the resulted SSC with 10 % AM exhibits the best energy storage properties with energy density of 5.4 Wh kg −1 and power density of 1600 W kg −1 . Hopefully, SSC via in-suit polymerization in MPC paste can be integrated with solar panels to generate and store energy in building structures. • PAM/MPC composite electrolyte is prepared via in-situ polymerization. • Compared with direct addition of PAM, dosage of AM increases from 5 % to 40 %. • As AM dosage rises, ionic conductivity of IPSE rises with compressive strength. • IPSE with 40 % AM shows the best multifunctionality of 54 mS cm −1 and 30.2 MPa. • SSC with 10 % AM has the highest energy density of 5.4 Wh kg −1 (1600 W kg −1 ).