ANODE PROPERTIES AND DIFFUSION-COEFFICIENT OF LITHIUM OF PITCH-BASED CARBON POWDER

Coal pitch based carbon powder, which was prepared at 1400 degrees C, was tested as the anode material of lithium secondary batteries. It sh owed a discharge capacity of 180 mAh/g at the 2nd cycle and it decreas ed to 150 mAh/g at the 10th cycle. Diffusion coefficients of lithium, (D) over bar(Li) in the carbon powder were measured by using two diffe rent electrochemical methods, i.e., the current pulse relaxation metho d (CPR) and the potential step chronoamperometric method (PSCA). The t wo sets of (D) over bar(Li) values agreed within one order of magnitud e, and the observed (D) over bar(Li) value decreased from 2.5x10(-8) c m(2)/sec. at X=0.05 to 1.6x10(-9) cm(2)/sec. at X=0.4 with increasing X in LiXC6.