Effects of the macroscopic structure of carbon black on its behaviour as the anode in a lithium secondary cell

The anodic behaviour of various carbon black (CB) samples prepared by the oil furnace method has been investigated in 1 M LiPF6 solution in ethylene carbonate-1,2-dimethoxyethane 50/50 (by volume). These CB samples had different macroscopic structures, though their microscopic parameters such as d002 and Lc remained constant substantially. The irreversible capacity at the initial reduction stage increased almost linearly with the BET surface area. The reversible capacity, on the other hand, showed no correlation with the BET area and was large for a highly aggregated coarse CB sample. The neck position connecting two primary CB particles was considered to be mainly active for the electrochemical insertion/extraction of lithium including effective electrolyte penetration on to the carbon surface.