Materials Combining Asymmetric Pore Structures with Well-Defined Mesoporosity for Energy Storage and Conversion.

Porous materials design often faces a trade-off between the requirements of high internal surface area and high reagent flux. Inorganic materials with asymmetric/hierarchical pore structures or well-defined mesopores have been tested to overcome this trade-off, but success has remained limited when the strategies are employed individually. Here, the attributes of both strategies are combined and a scalable path to porous titanium nitride (TiN) and carbon membranes that are conducting (TiN, carbon) or superconducting (TiN) is demonstrated. These materials exhibit a combination of asymmetric, hierarchical pore structures and well-defined mesoporosity throughout the material. Fast transport through such TiN materials as an electrochemical double-layer capacitor provides a substantial improvement in capacity retention at high scan rates, resulting in state-of-the-art power density (28.2 kW kg-1) at competitive energy density (7.3 W-h kg-1). In the case of carbon membranes, a record-setting power density (287.9 kW kg-1) at 14.5 W-h kg-1 is reported. Results suggest distinct advantages of such pore architectures for energy storage and conversion applications and provide an advanced avenue for addressing the trade-off between high-surface-area and high-flux requirements.