Self-Assembly of Antisite Defectless nano-LiFePO4@C/Reduced Graphene Oxide Microspheres for High-Performance Lithium-Ion Batteries

LiFePO4@C/reduced graphene oxide (rGO) hierarchical microspheres with superior electrochemical activity and a high tap density were first synthesized by using a Fe3+-based single inorganic precursor (LiFePO4OH@RF/GO; RF=resorcinol-formaldehyde, GO=graphene oxide) obtained from a template-free self-assembly synthesis followed by direct calcination. The synthetic process requires no physical mixing step. The phase transformation pathway from tavorite LiFePO4OH to olivine LiFePO4 upon calcination was determined by means of the insitu high-temperature XRD technique. Benefitting from the unique structure of the material, these microspheres can be densely packed together, giving a high tap density of 1.3gcm(-3), and simultaneously, defectless LiFePO4 primary nanocrystals modified with a highly conductive surface carbon layer and ultrathin rGO provide good electronic and ionic kinetics for fast electron/Li+ ion transport.