Preparation of CF_x@C Microcapsules as a High-rate Capability Cathode of Lithium Primary Battery

摘要

The Core-shell structure carbon-coated graphite fluoride (CFx@C) microcapsules were prepared bymicroencapsulation and carbonization. The CFx@C has a spherical shape and the carbon coating isconstructed of thousands of carbon micro-shperes. With the exterior conductivity provided by thecarbon coating, CFx@C cathode achieves a higher energy density and a higher power density than the-1 -1 pristin CFx. The energy density is increased from 505 Wh Kg by CFx to 1171 Wh Kg by CFx@C at0.5 C and the maximun discharge rate is improved from 0.5 C by CFx to 5 C by CFx@C. Both fullydischarged (at 0.1 C) pristin CFx and CFx@C cathodes are studied to reveal the effect mechanism. Thehigh power density is attributed to: 1) the enhanced combination of CFx@C and acetylene black byplyurea guarantees the electrons transferring from Al collector to the surface of CFx@C; 2) the carboncoating of CFx@C with a good electronic conductivity accelerates the shift of electrons to the GICinterface; 3) the carbon coating which shows an porous surface enlarges the contact area and can store+ much electrolyte and allows more channels for the Li ion transferring.