Enhanced electrochemical performance of LiFe0.4Mn0.6(PO4)1 − x(BO3)x as cathode material for lithium ion batteries

• B-substituted LiFe0.4Mn0.6(PO4)1 − x(BO3)x synthesized as a cathode material.
• LiFe0.4Mn0.6(PO4)0.995(BO3)0.005 shows discharge capacity of 159 mAh g− 1 at 0.1 C.
• LiFe0.4Mn0.6(PO4)1 − x(BO3)x exhibited enhanced cycleability with high C rate.
• Uniformly introduced BO33 − boron polyanion is observed by EELS spectroscopy.

A potential cathode material for lithium ion batteries has been developed using a boron polyanion substituted lithium iron manganese phosphate, LiFe0.4Mn0.6(PO4)1 − x(BO3)x (x = 0 to 0.03). Without any external carbon source, the material has been synthesized by solid-state reaction using ball-mill and was subsequently characterized by X-ray diffraction, scanning electron microscopy, electron energy loss spectroscopy, X-ray photoelectron spectroscopy, cyclic voltammetry, and galvanostatic charge–discharge measurement. The LiFe0.4Mn0.6(PO4)1 − x(BO3)x samples show a single-phase crystalline nature with X-ray diffraction analysis, and enhanced discharge capacity at various C-rates as compared to that of pure LiFe0.4Mn0.6PO4. Among several LiFe0.4Mn0.6(PO4)1 − x(BO3)x samples, LiFe0.4Mn0.6(PO4)0.995(BO3)0.005 demonstrated the best cycleability, exhibiting an initial discharge capacity of 159.4 mAh g− 1 at 0.1 C and 113 mAh g− 1 at 3 C. LiFe0.4Mn0.6(PO4)1 − x(BO3)x demonstrates enhanced electrochemical properties with excellent reversible cycling via boron polyanion substitution.

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