Analysis of inner-pore structure of carbon materials using Li and Xe NMR

Abstract

Closed pores in non-graphitazable carbon (hard carbon) are the reason for some unique properties for lithium intercalation. Our group investigated intercalated Li in hard carbon, which is used for the anode active material of lithium ion batteries for electric vehicles, using solid state 7Li NMR. The correlation between deposition of lithium clusters in the pores and the state of charge were elucidated. The growth of the porous structure of hard carbon was also investigated using 129Xe NMR porosimetry. Xe NMR could evaluate pores in hard carbon that were hard to investigate by adsorption isotherm measurement. A Li NMR study for a ternary graphite intercalation compound consisting of alkylamine and Li is also presented.