Unveiling Na‐ion storage mechanism and interface property of layered perovskite Bi2TiO4F2@rGO anode in ether‐based electrolyte

Abstract

AbstractTo unveil the charge storage mechanisms and interface properties of electrode materials is very challenging for Na‐ion storage. In this work, we report that the novel layered perovskite Bi2TiO4F2@reduced graphene oxides (BTOF@rGO) serves as a promising anode for Na‐ion storage in an ether‐based electrolyte, which exhibits much better electrochemical performance than in an ester‐based electrolyte. Interestingly, BTOF@rGO possesses a prominent specific capacity of 458.3–102 mAh g−1/0.02–1 A g−1 and a high initial coulombic efficiency (ICE) of 70.3%. Cross‐sectional morphology and depth profile surface chemistry indicate not only a denser reactive interfacial layer but also a superior solid electrolyte interface film containing a higher proportion of inorganic components, which accelerates Na+ migration and is an essential factor for the improvement of ICE and other electrochemical properties. Electrochemical tests and ex situ measurements demonstrate the triple hybridization Na‐ion storage mechanism of conversion, alloying, and intercalation for BTOF@rGO in the ether‐based electrolyte. Furthermore, the Na‐ion batteries assembled with the BTOF@rGO anode and the commercial Na3V2(PO4)2F3@C cathode exhibit remarkable energy densities and power densities. Overall, the work shows deep insights on developing advanced electrode materials for efficient Na‐ion storage.