Enhanced Electrochemical Performance of LiMn0.75Fe0.25PO4Nanoplates from Multiple Interface Modification by Using Fluorine-Doped Carbon Coating

Abstract

© 2017 American Chemical Society. We report a novel composite of fluorine-doped carbon-decorated LiMn0.75Fe0.25PO4(LMFP) nanoplates synthesized via a facile method by using hybrid sucrose and polyvinylidene fluoride as carbon and fluorine sources. In the composite, the thin LMFP nanoplates expose large amounts of (010) crystal face which shortens the Li+ion diffusion distance. Also, the fluorine-doped carbon coating layer can provide a sufficient pathway for rapid electron transport, and the partially formed metal fluorides in the interface between the LMFP nanoplates surface and fluorine-doped carbon coating layer will help reduce charge transfer resistance. Because of this unique structure, the resulting product exhibits a superior discharge capacity of 162.2 mA h g-1at the 1 C current rate, and the capacity is retained 94.8% over 200 cycles. Furthermore, this material also can deliver a reversible capacity of 130.3 mA h g-1at an ultrahigh current rate of 20 C, in which the discharge procedure can be accomplished only in 144 s. The celerity and cycling capability of the prepared material endow it with great potential for application in high performance lithium-ion batteries.