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

Abstract

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 (LiFePO₄ OH@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 LiFePO₄ OH to olivine LiFePO₄ upon calcination was determined by means of the in situ 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 1.3 g cm^-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.