Hierarchical macro–mesoporous oxides and carbon materials via homopolymer-assisted dual phase separation

The design of hierarchical porous materials with tunable macro- and mesopore architectures is critical for enhancing mass transport, surface accessibility, and nanoscale reactivity across a wide range of functional applications. Inspired by the phase behavior of immiscible polymer blends, we present a facile and generalizable strategy, termed homopolymer-assisted regulation of macro- and microphase separation for hierarchical porosity (HARMONY). The method integrates block copolymer (BCP)-driven microphase separation with homopolymer (HP)-induced macrophase separation in a single processing step, enabling independent tuning of mesopores (7–24 nm) and macropores (63–226 nm). Mesopores are tuned by BCP composition and molecular weight, whereas macropores are controlled by HP molecular weight and mass loading. Systematic variation of these parameters reveals quantitative correlations between synthesis conditions and resulting pore architectures, offering practical guidelines for designing hierarchical porosity. The versatility of HARMONY is demonstrated across multiple inorganic compositions, including aluminosilicate (AS), transition metal oxides (e.g., TiO₂, Nb₂O₅), and carbon. As a proof of concept, a hierarchically porous carbon (hC) was employed as an anode material for potassium-ion hybrid capacitors, achieving enhanced capacity, rate performance, and cycling stability. These findings establish general design principles for the controllable fabrication of hierarchically porous inorganic materials.