Electrochemically Driven Transformation of Amorphous Carbons to Crystalline Graphite Nanoflakes: A Facile and Mild...

Although, in the carbon family, graphite is the most thermodynamically stable allotrope, conversion of other carbon allotropes, even amorphous carbons, into graphite is extremely hard. We report a simple electrochemical route for the graphitization of amorphous carbons through cathodic polarization in molten CaCl₂ at temperatures of about 1100 K, which generates porous graphite comprising petaloid nanoflakes. This nanostructured graphite allows fast and reversible intercalation/deintercalation of anions, promising a superior cathode material for batteries. In a Pyr₁₄ TFSI ionic liquid, it exhibits a specific discharge capacity of 65 and 116 mAh g^-1 at a rate of 1800 mA g^-1 when charged to 5.0 and 5.25 V vs. Li/Li⁺ , respectively. The capacity remains fairly stable during cycling and decreases by only about 8 % when the charge/discharge rate is increased to 10000 mA g^-1 during cycling between 2.25 and 5.0 V.