In-situ plasma assisted formation of graphitic nanosheet supported N-doped carbon-coated antisite defectless LiFePO4 as a high-performance cathode material for lithium-ion batteries

Abstract

In this work, an in situ plasma method is developed for the synthesis of Fe•Li-antisite-free LiFePO4 nanoparticles with full nitrogen-doped carbon coating (NC) and graphitic nanosheet support (LFP@NC/GNS). Briefly, plasma discharge promotes in-situ formation of graphitic nanosheets on LFP@NC via Fe0-catalyzed glucose pyrolysis and simultaneously removes Fe•Li antisites in LFP. The resultant LFP@NC/GNS shows enhanced reversible capacities as a cathode material for Li-ion batteries. Even at the super-high current rate of 150 C, LFP@NC/GNS still delivers a stable reversible capacity of 100.7 mAh g−1. Furthermore, LFP@NC/GNS exhibits a super-long cycling stability with no apparent capacity drop when charged/discharged at 10 C and 100 C for 1200 cycles. The absence of the Fe•Li antisites is expected to play a significant role in the high performance of LFP@NC/GNS because it provides further expedited Li+ diffusion paths in the LFP lattices, thereby allowing for ready migration of Li+ ions and better utilization of LFP. The full NC coating and GNS support also aid the performance of LFP@NC/GNS significantly because both can improve the Li storage kinetics and utilization of the active material.