High multifunctional performance structural supercapacitor with Polyethylene oxide cement electrolyte and reduced graphene oxide@CuCo2O4 nanowires

Abstract Structural supercapacitors can provide load-bearing and energy storage capacities for zero energy buildings. Unfortunately, trade-off between electrical and mechanical performance of cement electrolytes as well as rigid contact of electrolyte/electrode is great challenge. Herein, polyethylene oxide (PEO) is firstly exploited with 5 wt% KOH or LiOTf to fabricate polymer cement electrolytes with various potential windows via hydration synthesis of ordinary Portland cement (OPC). The prepared polymer cement electrolytes with 2 wt% PEO essentially exhibit optimum balance of compressive strength and ionic conductivity. The reduced graphene oxide (rGO)@CuCo2O4 nanowires utilize the excellent capacitance of binary transition metal oxides as well as long term stability of carbon-based material. Subsequently, two structural supercapacitor devices are assembled with the polymer cement electrolytes and rGO@CuCo2O4 nanowires. The device A presents an energy density of 0.2 mWh/cm2 and areal capacitance of 439.35 mF/cm2. The device B delivers an energy density of 0.74 mWh/cm2 and areal capacitance of 407.07 mF/cm2. Consequently, the energy efficiency of the electrodes in device A and device B can achieve 18.1% and 17.0%, respectively. The rational combination of electrode and PEO cement electrolyte for structural supercapacitor device paves the well balance to the integration of zero energy buildings and electrochemical energy storage.