Nanoporous polymer-derived activated carbon for hydrogen adsorption and electrochemical energy storage
Nikolaos Kostoglou, Christian Koczwara, Sebastian Stock, Christos Tampaxis, Georgia Charalambopoulou, Theodore Steriotis, Oskar Paris, Claus Rebholz, Christian Mitterer
Abstract
The development and in-depth characterization of multifunctional materials with versatile use in energy and environmental applications has been a topic of on-going investigations. In this work, a nanoporous polymer-/polyaniline-derived activated carbon (PDAC), with large surface area (~2200 m2/g) and large pore volume (~1 cm3/g), was thoroughly studied towards its applicability for H2 storage and supercapacitor energy storage. The PDAC demonstrated a superior H2 adsorption performance under cryogenic conditions, reaching a high and fully reversible excess gravimetric H2 uptake of ~5.5 wt% at 77 K and ~60 bar, along with a ~8.3 kJ/mol heat of adsorption at zero coverage. Furthermore, thin PDAC electrodes with an aqueous CsCl electrolyte were combined in a supercapacitor cell that exhibited a gravimetric capacitance of ~130 F/g for a 0.5 mV/s scanning rate along with a 99% coulombic efficiency and a 100% capacitance retention after 2500 charge/discharge cycles. The PDAC material showed substantially improved H2 and electrochemical energy storage performance compared to a well-established commercial activated carbon, which is attributed to the overall smaller pore sizes of the PDAC structure.