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

Abstract

Although, in the carbon family,graphite is the most thermodynamically stable allotrope,c onversion of other carbon allotropes,e ven amorphous carbons,i nto graphite is extremely hard. We report as imple 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,p romising as uperior cathode material for batteries.I naPyr 14 TFSI ionic liquid, it exhibits aspecific discharge capacity of 65 and 116 mAh g À1 at ar ate of 1800 mA g À1 when charged to 5.0 and 5.25 Vv s. Li/ Li + ,r espectively.T he capacity remains fairly stable during cycling and decreases by only about 8% when the charge/ discharge rate is increased to 10000 mA g À1 during cycling between 2.25 and 5.0 V.Supportinginformation and the ORCID identification number(s) for the author(s) of this article can be found under http://dx.

Green synthesis of graphite from CO2 without graphitization process of amorphous carbon

“…Synthetic graphite, as a type of crystalline carbon with tunable microstructure and morphology, of which the synthesis procedures generally contain two sequential processes: carbonization of carbon precursors and graphitization of amorphous carbon [19][20][21][22] . During the carbonization of carbon precursors such as biomass and organic materials, considerable quantities of greenhouse gas (CO 2 ) and hazardous gases (e.g., CO, SO 2 , and NO x ), which are one of the main causes of global warming and environmental pollution, are emitted into the atmosphere.…”

“…After carbonization, the carbon precursors are converted into graphitizable or nongraphitizable carbon. Direct graphitization of graphitizable carbon at high temperature (~3000°C) and catalytic graphitization of non-graphitizable carbon at a temperature of~1000°C are the two primary routes of transforming amorphous carbon into graphite 22,23 . Moreover, the transition metal catalysts are found to be difficult to separate from synthetic graphite 24 .…”

Molten‐NaNH2 Densified Graphene with In‐Plane Nanopores and N‐Doping for Compact Capacitive Energy Storage

“…The expansion temperature here was set as 300 °C to remove the sulfuric acid simultaneously by decomposition. Subsequently, DNPG was prepared by treating the EG in molten sodium amide (NaNH 2 ) at about 320 °C for 10 h. Molten salt processes have been proposed for the synthesis and modification of various carbons, aiming at porous carbons in particular . Here we made an unprecedented finding that the molten NaNH 2 treatment can lead to densification and N‐doping of EG as well as creating nanopores on graphene sheets.…”

Non‐oxidative methane conversion in diffuse, filamentary, and spark regimes of nanosecond repetitively pulsed discharge with negative polarity

“…The value of the brown area was very similar to that of black ring, which means the brown area had similar structure as the black area with a thinner thickness. Peng et al reported that the graphite is the most thermo‐dynamically stable allotrope of carbon, and a graphitization process requires high temperature over 3,300 K. The temperature of the spark discharge was insufficient for complete graphitization, but enough for a partial graphitization, in which most of amorphous carbons remained nongraphitized.…”