パルスCVD法によるリチウムイオン電池負極用黒鉛MCMBへのパイロカーボンコーテイング

Abstract

Pyrocarbon was coated on graphitized Mesocarbon Microbeads (MCMB) form 30 % C3H8-H2 at 950℃ using pressure-pulsed chemical vapor deposition. It was revealed from TEM， XRD and Raman spectroscopy that the crystallinity of pyrocarbon films is lower than that of the graphitized MCMB as the core carbon. Large irreversible capacity was observed in the original MCMB in PC/EC/DEC(2:1:1 vol.%) electrolyte， however， irreversible capacity was reduced by coating with 3mass% pyrocarbon， which would be attributed to the low crystallinity of pyrocarbon. Under the condition of high current density of 450 mA/g， the pyrocarbon-coated sample showed 1.3 times as high capacity as the original MCMB in PC-based electrolyte.