Microstructural Effect of Carbon Blacks for the Application in Lithium Ion Batteries

Carbon blacks commercially available (Super P, SP and Ketjen black, KB) and synthesized by a liquid phase plasma process (SC) were compared for the lithium ion battery applications as an anode material. All the carbon black samples were spherical with sizes in the range of 30--50 nm. The Brunauer--Emett--Teller (BET) specific surface areas of the SP, KB, and SC samples were measured to be 62, 1452, and 895 m 2 /g, respectively. The overall fraction of the ordered structure, represented by the ratio of the G-band to the D-band (G/D raio) from Raman spectra, was highest for the SC sample. A large specific surface area of the samples was found to play an important role in storing lithium ions, contributing to high initial charge capacities, 2050 mAh/g for KB and 1542 mAh/g for SC. The initial charge--discharge coulombic efficiency of the samples was strongly influenced by the solid electrolyte interface (SEI) formation behavior. The behavior of SEI formation seemed to be affected by the microstructural characteristics of the carbon blacks such as crystallinity and G/D ratio. The SC sample having a high G/D ratio and a slight variation without a peak of $dQ/dV$ with potential showed a small initial capacity irreversibility.