Improving carbon-cement electrode by refining percolation network: Optimization of carbon materials and preparation methods

Carbon-cement composite is a promising material to realize structural-functional integration for building energy storage. By combining carbon fiber (CF) and nano- carbon black (nCB) with optimized dispersion method, this study significantly improved the conductive percolation network and energy storage efficiency of carbon-cement composite electrodes. Experimental results demonstrate that CF, as a bridge between nCB agglomerates, can significantly increase the energy density of nCB-cement supercapacitors. Notably, a combination of 2 vol% CF + 5 % nCB delivers comparable electrical performance (30.26 μWh/cm³) to 15 % nCB, while maintaining considerable compressive strength (36.88 MPa). Moreover, the ultrasonic dispersion of T-20 surfactant has been proven to be an effective method for promoting the dispersion of nCB, which is positively correlated with electrical performance. The molding pressure exerts dual effects on the conductive network regulation: reducing macro-pores while simultaneously causing excessive densification that impedes ion transport. The findings demonstrate that in carbon-cement composites materials, both conductive and energy storage carbon materials play important roles. This provides insights for the performance optimization of nCB-cement energy storage materials in subsequent research.