Electrochemical Approach for the Synthesis of Carbon-Metal Fluoride Nanocomposites for Lithium Batteries

Thursday, 28 May 2015: 08:20
Salon A-5 (Hilton Chicago)
A. R. Munnangi (Helmholtz Institute Ulm (HIU)) and M. Fichtner (Helmholtz Institute Ulm (HIU), Karlsruhe Institute of Technology (KIT))
Metal fluorides are assuming importance as electrode materials for rechargeable lithium batteries as they possess high gravimetric and volumetric energy densities and are thermally stable. However, metal fluorides are insulators, exhibits sluggish kinetics and undergo large volume changes during electrochemical discharge and charge. Mechanochemical synthesis of carbon metal fluoride nanocomposites (CMFNCs) was suggested to address these problems [1]. Recently we reported a facile chemical approach for the synthesis of C-FeF2 nanocomposites by reductive intercalation method using CFx as a precursor [2]. The C-FeF2 nanocomposites obtained by this method showed high reversible lithium storage due to the incorporation of nanocrystalline FeF2 in electronically well-connected graphitic domains.

Here we propose and demonstrate a rather general approach for the synthesis of CMFNCs at room temperature using CFx as precursor. CFx is known as a cathode material for lithium primary batteries. During discharge process lithium reacts with CFx and form C+LiF. In other words this is an electrochemical method for the synthesis of C-LiF nanocomposites. Fundamentally, it is possible to extend this approach for the synthesis of other C-MFx nanocomposites if the reaction of metal with CFx is thermodynamically feasible provided with suitable metal ion transporting electrolyte. Figure 1 show the discharge curve obtained with CFx cathode and Fe metal foil as anode and Fe2+ transporting liquid electrolyte. During the discharge process the Fe2+ is released into the electrolyte at anode and the CFx is reduced at cathode to form C-FeF2. The discharged electrode was analyzed by XRD and formation of FeF2 is confirmed. The as synthesized C-FeF2 nanocomposites showed excellent reversible lithium storage properties. Further, we have succeeded in the synthesis of various C-MFx nanocomposites by the proposed electrochemical approach. 


  1. F. Badway, N. Pereira, F. Cosandey, G. G. Amatucci, J. Electrochem. Soc. 2003, 150, A1209.
  2. M. Anji Reddy, B. Breitung, V.S.K. Chakravadhanula, C. Wall, M. Engel, C. Kübel, A. K. Powell, H. Hahn and M. Fichtner, Adv. Energy Mater. 2013, 3(3), 308.