Hexagonal platelet graphite and its application in Li-ion batteries

Abstract Highly crystalline graphite powder was prepared from the low temperature (800–1000 °C) graphitization of renewable materials using a magnesium catalyst. The magnesium catalyst was easily removed, resulting in a highly pure graphite product. The graphite has an interesting microstructure, consisting of mainly hexagonal platelets (up to 10 μm), and some graphene particles. This unique microstructure results in a high specific surface area. However, the graphite has a high density and a degree of graphitization higher than some conventional artificial graphites made at 2850 °C. When cycled in Li half-cells, the graphite displays good cycling stability and high reversible capacity (up to 370 mAh g −1 ). After carbon coating, the surface area of the graphite is greatly reduced, and its coulombic efficiency is greatly improved, resulting in performance that is comparable to commercial high surface area battery synthetic graphites. Graphite made by low temperature Mg catalyzation of renewable plant derived precursors represents a new direction for research in the development of primary synthetic graphites and the application of sustainable materials. We anticipate that Mg catalyzed graphites could have interesting applications in batteries, as catalyst supports or in other fields.