Realistic atomic model for charge storage and charging dynamics of amorphous porous carbons

Amorphous porous carbons have been widely used as electrodes for energy storage. However, due to their structural heterogeneity and complex pore topology, the absence of reliable atomic carbon models hinders understanding energy storage mechanisms through molecular simulations. Here, we develop a modeling approach capturing the rich experimental information of small angle X-ray scattering, gas adsorption, and material density, integrating three-dimensional morphology construction with atomic structure generation. Using the built atomic model, constant-potential molecular simulations are performed to investigate the capacitive behavior of amorphous porous carbons, well-validated by experimental measurements of capacitance and impedance. Voronoi sphere analyses uncover the interplay between pore structure and charge storage: ultramicropores (< 0.7 nm) are found to enhance the capacitance through ion exchange, while large micropores (> 0.7 nm) exhibit lower capacitance with negligible ion number change. The charging dynamics are quantified by the proposed multi-scale impedance model, bridging microscopic simulations and macroscopic experiments. This modeling framework paves the way toward molecular understanding of energy storage in amorphous porous materials.