We report the performance of a series of hierarchical porous carbons (HPCs) with extremely high surface areas of up to 2340 m2 g-1 with total pore volume of up to 3.8 cm3 g-1 as supports for sulfur for Li-S batteries. The hierarchical structure of the carbon originating from interconnected large mesopores (10-50 nm), small mesopores (2-10 nm) and micropores (<2 nm) makes the total available surface area highly accessible, resulting in excellent electrode kinetics. At high C-rates of 2 C and 5 C, large specific capacities of 647 mA h g-1 and 503 mA h g-1, respectively, were obtained after 200 cycles. In addition, we also systematically show that the cyclic stability is independent of the size of the pores sulfur is initially confined in, when LiNO3 is used as the electrolyte additive, indicating that capacity fade due to polysulfide shuttle is effectively eliminated and that it is not related to pore size anymore.
Sahore, R., Estevez, L. P., Ramanujapuram, A., DiSalvo, F. J., & Giannelis, E. P. (2015). High-rate lithium–sulfur batteries enabled by hierarchical porous carbons synthesized via ice templation. Journal of Power Sources, 297, 188–194. doi:10.1016/j.jpowsour.2015.07.068
This work is supported by the Energy Materials Center at Cornell (EMC2) - an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences (DE-SC0001086), King Abdullah University of Science and Technology (KAUST), KAUST baseline fund (KUS-C1-018-02). EPG acknowledges support from the NSF-PFI program (IIP-1114275). This work made use of the Cornell Center for Materials Research Shared Facilities supported through the NSF MRSEC program (DMR-1120296). We would like to thank Christos Tampaxis and Dr. Theodore Steriotis for their help with the porosity measurements, and, Mian Pan (Cornell University) and Tiffany Williams (Cornell University) for their help with Raman Spectroscopy of the carbons.