Enhanced methane storage of chemically and physically activated carbide-derived carbon

• Published in: Journal of power sources Vol. 191; no. 2; pp. 560 - 567
• Main Authors: Yeon, Sun-Hwa, Osswald, Sebastian, Gogotsi, Yury, Singer, Jonathan P., Simmons, Jason M., Fischer, John E., Lillo-Ródenas, María A., Linares-Solano, Ángel
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01-06-2009; Elsevier
• Subjects: Activation; Applied sciences; Carbide-derived carbon; Energy; Energy. Thermal use of fuels; Exact sciences and technology; Methane storage; Pore size; Small-angle X-ray scattering; Transport and storage of energy; Methane storage; Pore size; Activation; Carbide-derived carbon; Small-angle X-ray scattering; Measurement; Methane; Carbon dioxide; Small angle X ray scattering; Adsorption; Storage capacity; Activated carbon; Porosity; Surface area; Energy storage
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2009.02.019

Carbide-derived carbons (CDCs) produced by chlorination of carbides offer great potential for precise pore size control at the atomic level, making them attractive candidates for energy storage media. CDCs activated with CO
2 or KOH possess distinct improvements in porosity, displaying specific surface areas above 3000
m
2
g
−1 and pore volumes above 1.3
cm
3
g
−1. These correspond to gravimetric methane uptake of 16
wt% at 35
bar and 25
°C, close to the currently best reported material PCN-14, a metal-organic framework (MOF), at 35
bar and 17
°C or KOH activated anthracite at 35
bar and 25
°C. The best excess gravimetric methane uptake is obtained with a TiC-derived CDC activated with CO
2 at 975
°C for 2
h, namely a very large surface area of 3360
m
2
g
−1 resulting in 18.5
wt% at 25
°C and 60
bar. To obtain realistic volumetric methane capacity, the packing density of completely dried CDC was measured, from which we obtain excess capacity of 145
v(STP)
v
−1 from CDC activated with CO
2 at 875
°C for 8
h, 81% of the DOE target (180
v(STP)
v
−1) at 35
bar and 25
°C. From small-angle X-ray scattering (SAXS) measurements, pore radii of gyration (
R
g
) between 0.5
nm and 1
nm are determined. Temperature-dependent methane isotherms show that the isosteric heat of adsorption reaches 24
kJ
mol
−1 at the initial stage of low loading.