High-efficiency, self-grinding exfoliation of small graphene nanosheets from microcrystalline graphite driven by microbead milling as conductive additives

Direct mass exfoliation of graphene from bulk graphite with high yield and productivity for commercial applications is challenging. This work proposes self-grinding exfoliation using the mutual shear friction of graphite particles to fabricate graphene from microcrystalline graphite. The concept is implemented using microbeads as the grinding medium to drive the shear friction between graphite nanocrystals in a high-concentration paste. The proposed approach substantially improves graphene yield from 6.3% to 100% and simultaneously generates a record productivity of 7.5 g h−1 L−1, achieving total graphite-to-graphene conversion on the kilogram scale. The as-prepared graphene nanosheets have an average lateral size of 298 nm and the same C/O atomic ratio as the pristine graphite. In addition, the well-exfoliated, small nanosheets display good electrical conductivity and exhibit significant potential as conductive additives that improve the specific capacity and cyclic stability of Li-ion batteries better than commercial carbon-based conductive particles.