Directed Construction of Hierarchical Porous Carbon With Ultrahigh Surface Area for High‐Density Methane Storage at Room Temperature

Abstract

ABSTRACT Efficient methane storage remains a fundamental challenge for the deployment of adsorbed natural gas technologies, owing to the long‐standing difficulty of simultaneously achieving high gravimetric and volumetric storage capacities. Here, we report a directed materials‐design strategy that links molecular precursor topology to defect evolution and hierarchical pore formation in porous carbons. By exploiting the distinct pyrolytic topologies of cyanide‐based ionic liquid anions, we program defect densities in carbon frameworks and guide the development of micro‐mesoporous architectures through chemical activation. This approach yields a hierarchical porous carbon with an ultrahigh Brunauer‐Emmett‐Teller area of 5011 m 2  g −1 and a physically accessible pore volume of 2.48 cm 3  g −1 as determined by skeletal density and tap density measurements, enabling exceptional methane storage performance at room temperature. At 298 K and 100 bar, this material achieves a gravimetric adsorption capacity of 0.48 g g −1 . Accordingly, its volumetric adsorption capacity reaches 228 cm 3 (Standard temperture and pressure, STP) cm −3 at a tap density of 0.337 g cm −3 and 275 cm 3 (STP) cm −3 at a compacted density of 0.407 g cm −3 . Beyond methane storage, our findings establish a generalizable paradigm for constructing high‐performance porous carbons by topologically programming defects and pore hierarchies, with implications for energy storage and gas adsorption technologies.