Nanoporous polymer-derived activated carbon for hydrogen adsorption and electrochemical energy storage

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 m ²/g) and large pore volume (~1 cm ³/g), was thoroughly studied towards its applicability for H ₂ storage and supercapacitor energy storage. The PDAC demonstrated a superior H ₂ adsorption performance under cryogenic conditions, reaching a high and fully reversible excess gravimetric H ₂ 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 H ₂ 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.