Comparative Study on the Hydration, Mechanical Properties, and Energy Storage Performance of MPC-Based Solid...

Polyacrylamides (PAMs) exhibit variable molecular characteristics, exerting different effects on the macro- and micro-properties of cement when used as cement modifiers. In this study, three different ionic polyacrylamides, namely anionic PAM (APAM), cationic PAM (CPAM), and nonionic PAM (NPAM), were employed to investigate their impacts on the microstructure, hydration, mechanical properties, and electrochemical energy storage characteristics of magnesium phosphate cement (MPC). Microstructural characterization methods, including Mercury Intrusion Porosimetry (MIP), Scanning Electron Microscopy (SEM), Fourier transform infrared (FTIR), etc., were employed to elucidate the phase composition, micromorphology, and pore structure of the modified MPC. Furthermore, electrochemical testing methods such as Cyclic Voltammetry (CV), Galvanostatic Charge-Discharge (GCD), and Electrochemical Impedance Spectroscopy (EIS) were conducted to reveal the energy storage characteristics of supercapacitors. The results indicate that all three PAMs retarded the hydration of MPC, optimized the pore size distribution, and increased the compressive strength of MPC. In terms of electrochemical performance, the ionic conductivity of MPC electrolyte modified by NPAM and APAM exhibited an opposite trend to that of CPAM as the dosage increased. At dosages of 0.5% (NPAM), 1.5% (CPAM), and 0.75% (APAM), the assembled supercapacitors using PAM-modified MPC electrolyte exhibited excellent areal capacitance and energy density, reaching a maximum areal capacitance of 1060 mF cm^-2 and an energy density of 0.147 mWh cm^-2.