Simultaneous exfoliation/fluorination for the preparation of fluorinated exfoliated graphite with high power densities in primary lithium batteries

•Fluorinated expanded graphites were prepared using two routes.•High content of the (C2F)n structural type and a significant proportion of sp2 carbons allow the electrochemical performance to be improved in primary Li battery.•Faradic yield close to 100% up to 6C discharge rates is achieved.•A good compromise between the energy and power densities is obtained. Fluorinated carbons combining accordion-like morphology, high content of (C2F)n phase (43%), and residual non-fluorinated carbons were synthetized by two routes, i.e. fluorination of expanded graphite and simultaneous exfoliation/fluorination of expandable graphite. The latter allows the synthesis in a one-step process to be achieved. Accordion-like morphology allows the accommodation of LiF without detrimental accumulation onto the fluorocarbon sheet edges during the discharge in primary lithium battery. The faradic yield is then close to 100 % up to a discharge rate of 6C. Residual sp2 carbons (sub-fluorination) ensure the electron flux during the electrochemical process and enhance the power density (9828 W.Kg-1). High content of (C2F)n phase results in a flat galvanostatic discharge curve. The combination of those features results in a good compromise between energy and power densities, making fluorinated exfoliated graphite one of the best cathodes for primary lithium batteries. [Display omitted]