Nanomechanics of liquid-quench-derived nanoporous amorphous carbon using ReaxFF molecular dynamics

Using liquid-quench reactive force field ReaxFF molecular dynamics, we revisit how changes within the method parameter space---annealing time, annealing temperature, and number of atoms---influence the nanostructure of sp²-dominated amorphous carbon at 1 g/cm{} mass density. Initially, the degree of graphitization, measured by the fraction of sp² bonding, increases monotonically with annealing time and temperature. Elevating the annealing temperature above 4000 K disrupts the balance between graphitic ordering and temperature-induced disorder, resulting in detrimental variations in the sp²-bonding fractions, ring-size distributions, pore formation, and mass-density uniformity. The widest nanopore-size distribution, extending into the mesopore range, is associated with the maximum graphitization, and is achieved through pore coarsening within the 4000 K annealing window. The system size maintains the robustness of these findings as the larger available volume promotes formation of larger nanopores. The obtained models were subsequently subjected to large uniaxial deformations, where representative 8000 atoms models display only modest residual elastic anisotropy, even in systems with both micro- and mesopores. The initial linear elastic response extends into a nonlinear elastic regime characterized by preservation of original carbon--carbon bonding and pore identity, but with pore stretching and progressive alignment of graphitic layers with the loading direction. At higher strains, heterogeneous ring-size expansion accompanied by sp²-chain formation at layer junctions enables extended plastic deformation prior to fracture. The intrinsic pore preservation across a large strain range, high strain tolerance, and gradual failure make microporous amorphous carbon particularly attractive as a durable carbon framework for next-generation ion-based battery electrodes.