Facile Synthesis of Carbon–Metal Fluoride Nanocomposites for Lithium‐Ion Batteries

Abstract

Metal‐fluoride‐based conversion materials have gained interest as cathode materials for lithium‐ion batteries due to their high theoretical energy densities. However, metal fluorides are electrically insulating and experience large volume changes during the charge and discharge processes. Effective synthesis of carbon–metal fluoride nanocomposites (CMFNCs) with stable morphology is one of the keys to achieve high capacities with sustainable cycle life. A general method for the synthesis of CMFNCs is described here. The redox‐mediated reaction between CFx and metal‐carbonyl precursors at relatively low temperatures leads to the formation of the respective CMFNCs. The reaction mechanism for the formation of CFx‐derived C–FeF2 nanocomposites has been investigated. Also, the synthesis and lithium‐storage properties of C–CoF2 and C–MoF3 nanocomposites are reported. In addition, by changing from CFx to graphite oxide and sulfur‐infused porous carbon, the synthesis of C–FeOx and C–FeS nanocomposites is reported.

Synthesis of Metal Nanoparticles and Metal Fluoride Nanoparticles from Metal Amidinate Precursors in 1-Butyl-3-Methylimidazolium Ionic Liquids and Propylene Carbonate

“…The galvanostatic charge/discharge profiles of the CoF 2 nanoparticles from decomposition of Co(AMD) 2 in [BMIm][BF 4 ] are presented in Figure . The redox plateau at the first discharge is 1.8 V, which is much lower than the theoretical value but comparable to that reported in the literature . Two oxidation plateaus in the charge process are in the potential ranges of 3.5 to 4.2 V and 4.2 to 4.8 V, which correspond to the processes of reconverting back into Co x F and CoF 2 , respectively .…”

“…The redox plateau at the first discharge is 1.8 V, which is much lower than the theoretical value but comparable to that reported in the literature. [58][59][60] Twoo xidation plateausi nt he chargep rocess are in the potential ranges of 3.5 to 4.2 Vand 4.2 to 4.8 V, which correspond to the processes of reconvertingb acki nto Co x Fa nd CoF 2 ,r espectively. [58] In the second discharge process, the slopep rocess before the plateau at 1.5 Vc an be assigned to the reduction of Co x F with lithium ions.…”

Electrochemical properties of lead fluoride electrode in fluoride shuttle battery

“…The PbF2-based compounds exhibit fluoride ion conductivity [18][19][20][21]; therefore, PbF2 was selected as an active material for the fluoride shuttle battery (FSB). It has been reported that the high adhesion state with carbon improved the charge and discharge capacities of metal fluorides for the active materials of LIBs due to the increased electronic conductivity [22][23][24][25][26][27][28][29][30][31][32]. This method can be used for the active material of the FSB.…”

Facile synthesis of C–FeF2 nanocomposites from CFx: influence of carbon precursor on reversible lithium storage

“…7,8 Alternatively, chemical methods have been reported to synthesize CMNFCs, which showed much higher cycling stability. [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24] Recently, we have reported a facile method for the synthesis of carbon-metal uoride nanocomposites by reacting graphite uoride (CFx) with iron pentacarbonyl (Fe(CO) 5 ) at 250 C. [25][26][27] The C-FeF 2 nanocomposites obtained by this method delivered high reversible capacity in lithium half cells. 25,27 Further, pretreatment of the CFx precursor by mechanical milling has a signicant impact on the reversible capacity, which we attributed to the reduced particle size of CFx.…”

“…More importantly, the reaction occurs in one step and is quick (could be nished in 1 h). 27 Further, addition of conductive carbon is not required to prepare the electrodes. In this study, we used various uorinated carbon compounds namely, petro-coke, carbon black, graphite, and carbon-bers to synthesize C-FeF 2 nanocomposites.…”