Enhancement of the Rate Capability of Graphite via the Introduction of Boron-oxygen Functional Groups

Abstract

The rate capability of graphite was enormously enhanced by introducing (meta)boric acid containing boron-oxygen groups onto its surface. Sample that had been heat-treated at 1000°C exhibited two times larger capacity at even 5C discharge rate than those of the as-received sample. The presence of (meta)boric acid on the surface of graphite reduced the resistance and capacitance of surface films related to lithium ion migration and charge transfer resistance. However, the samples heat-treated at temperatures above 1500°C showed no improvements in rate capability due to the disappearance of boron-oxygen groups from the graphite surface.