Synthesis and characterization of novel B/C materials prepared by 9-chloroborafluorene precursor

This paper describes a novel boron containing carbon (B/C) material which contains up to 7 mole% of boron atoms substitutionally incorporated in the graphitic structure. The chemistry involves the use of 9-chloroborafluorene precursor and the thermo-transformation reaction. 9-Chloroborafluorene was firstly oligomerized to mesophase boron containing pitch (B-pitch) which is processable by solution and melt. The mesophase B-pitch was then pyrolyzed at various temperatures (up to 2300°C) to produce B/C material with high yield (∼80%). During pyrolysis, boron is not only substitutionally incorporated in the graphitic structure but also enhances the graphitization reaction. An unusually large crystallite size and small d-spacing between interlayers of the B/C product was observed by X-ray diffraction.