Solid-state nuclear magnetic resonance studies of electrochemically discharged CFx

Electrochemical studies of three types of CFx (F – fiber based, C – petroleum coke based, G – graphite based) have demonstrated different electrochemical performances in previous work, with fiber based CFx delivering superior performance over those based on petroleum coke and graphite. 13C and 19F MAS (magic angle spinning) NMR techniques are employed to identify the atomic/molecular structural factors that might account for differences in electrochemical performance among the different types of CFx. Small quantitative variations of covalent CF and LiF are noted as a function of discharge and sp3 bonded carbons are detected in discharged F type of CFx.

Research highlights► CFx exhibits different electrochemical performance depending on morphology. ► C and LiF formation in discharged CFx are tracked by multinuclear solid state NMR. ► The fibrous morphology of CFx exhibits different LiF and C formation mechanisms. ► sp3 bonded C found in F-type CFx at greater DoD may be correlated with performance.