Mn2+- and Fe2+-doped LiNiPO4 cathode materials: structural, electrical, dielectric, and electrochemical properties

LiNiPO4, LiNi0.8Mn0.2PO4, and LiNi0.8Mn0.1Fe0.1PO4 cathodes were prepared via the solid-state reaction technique. The XRD analysis confirmed that all three samples were well crystallized and belonged to the Pnmb space group with an olivine-type structure. FTIR analysis identified the four fundamental stretching and bending vibration modes of ions (PO43- groups) in the tetrahedral sites of all samples. The electrical conductivity was found in the range of 1.51-2.16 x 10(-8) S/cm. The dielectric spectra revealed the existence of interfacial polarization Maxwell-Wagner-type dielectric dispersion in all samples. The frequency dependence study of electric modulus revealed the contribution of both long-range and short-range mobility of charge carriers in all samples. This study confirmed that single Mn2+ ions doping is more effective to enhance the electrical conductivity and electrochemical performance of LiNiPO4 cathode than Mn2+ and Fe2+ ions co-doping.

Automated summary

In this study, LiNiPO4, LiNi0.8Mn0.2PO4, and LiNi0.8Mn0.1Fe0.1PO4 cathodes were prepared via solid-state reaction technique and characterized by XRD and FTIR analysis. It was found that doping with Mn2+ ions alone was more effective in enhancing the electrical conductivity and electrochemical performance of the cathode compared to co-doping with Mn2+ and Fe2+ ions.