Comparative studies of MCMB and C-C composite as anodes for lithium-ion battery systems

Mesocarbon microbead (MCMB 2528) and C-C composite have been investigated as anodes for lithium-ion batteries using half-cells with lithium counter electrode and three electrode cell systems containing LiCoO2 cathode and lithium reference electrodes in 1 M LiPF6 electrolyte (EC/DMC 1:1 v/v). The test results show that the practical capacity of C-C composite anode is 50% higher than that of MCMB-based anode (based on total anode weight). The irreversible capacity loss of C-C composite is significantly lower than that of MCMB carbon. Lithium-ion cells made with C-C composite anode can accept repeated overdischarge without performance deterioration. The extra capacity of C-C composite can be utilized to improve energy density and safety issues related to overcharge of lithium-ion cells. Differential scanning calorimetry (DSC) results indicates that the thermal stability of fully charged C-C composite anode (lithiated anode) is much better than that of fully charged MCMB anode. (C) 2002 Elsevier Science B.V. All rights reserved.