Materials Combining Asymmetric Pore Structures with Well-Defined Mesoporosity for Energy Storage and Conversion
Sarah A. Hesse, Kevin Fritz, Peter A. Beaucage, R. Paxton Thedford, Fei Yu, Francis J. DiSalvo, Jin Suntivich, Ulrich Wiesner
Abstract
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.