3D porous cementitious electrolytes with “stream-reservoir” ionic channels for high multifunctional performance structural supercapacitors

Abstract

Structural supercapacitors (SSCs) have attracted extensive attention due to load bearing/energy storage in zero energy buildings (ZEBs). Unfortunately, SSCs normally suffer from low energy density owing to the conventional cementitious electrolytes' poor ionic conductivity and dissatisfactory interface bonding. Herein, a new “stream-reservoir” porous cementitious electrolyte is prepared by a simple foaming strategy. The ionic conductivity of the resulting material reaches 13.1 mS cm⁻¹. The “stream-reservoir” structure endows the cementitious electrolyte with abundant ion channels and certain mechanical stability, effectively reducing the interfacial contact resistance with the electrode. Based on the porous cementitious electrolyte, the fabricated load-bearing/energy storage integrated supercapacitor delivers an energy density of 32.8 μW h cm⁻² and a power density of 2.5 mW cm⁻² and suffers a small capacitance degradation. Additionally, the supercapacitor can maintain stable electrochemical behavior while withstanding external loads, which is a rarely studied aspect in other reports. The obtained multifunctional performances may provide intriguing opportunities for ZEBs and electrochemical energy storage.