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Electrochemically Driven Transformation of Amorphous Carbons to Crystalline Graphite Nanoflakes: A Facile and Mild Graphitization Method
Author(s) -
Peng Junjun,
Chen Nanqing,
He Rui,
Wang Zhiyong,
Dai Sheng,
Jin Xianbo
Publication year - 2017
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201609565
Subject(s) - graphite , intercalation (chemistry) , materials science , electrochemistry , amorphous carbon , amorphous solid , chemical engineering , ionic liquid , carbon fibers , cathode , inorganic chemistry , electrode , composite number , chemistry , crystallography , organic chemistry , metallurgy , catalysis , composite material , engineering
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 CaCl 2 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 Pyr 14 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.