A Novel Strategy for Preparing Nano-Sized and High-Performance LiMnxFe1−xPO4 Cathode Materials from Discarded LiMn2O4 and LiFePO4 Electrode

Abstract

The research strategy of using discarded lithium manganate (LiMn2O4, LMO) and lithium iron phosphate (LiFePO4, LFP) electrode materials to obtain lithium manganese iron phosphate (LiMnxFe1−xPO4, LMFP) materials with high energy density and ionic conductivity is increasingly highlighted as powerful and effective. The study explores a new strategy to prepare high-performance LMFP materials using high-temperature sintering based on the successful recovery of LMO and LFP electrode wastes. X-ray diffraction results show that the LMFP cathode materials are prepared successfully by using discarded LMO and LFP materials. LM0.4F0.6P and LM0.6F0.4P, whose manganese-to-iron molar ratio [MR(Mn/Fe)] 4:6 and 6:4, exhibit nano-sized olivine spheres with lattice diagram corresponding to the (101) crystal planes. The constant current curves show that LM0.6F0.4P has a specific discharge capacity of 154.4 mAh g−1 at 0.2 C. The capacity retention rate is maintained at 96.2% after 100 cycles. The cyclic voltammetry curves show that two distinct pairs of redox potentials appeared for LM0.6F0.4P in the voltage interval located at (3.63 V/3.43 V) and (4.18 V/3.87 V). Thus, the proposed strategy predicts that the discarded LMO and LFP can be used as raw materials to prepare high-performance LMFP cathode materials, significantly reducing energy consumption and environmental pollution.