Influence of micropore structure on Li-storage capacity in hard carbon spherules

Hard carbon spherules (HCS) were synthesized by a normal hydrothermal method (HCS1) and a microemulsion-mediated (reverse micelles) hydrothermal method (HCS2). The results from nitrogen adsorption isotherm at 77 K and carbon dioxide adsorption isotherm at 273 K showed that the micropores of HCS2 are smaller than that of HCS1. HCS2 with smaller micropores shows higher emf value and larger Li-storage capacity around 0 V while HCS1 with larger micropores exhibits better kinetic performance at high current density. It is found that micropore structure plays a key role in the thermodynamic and kinetic behaviors of Li-ion insertion and extraction process.