Electrochemical performance of cobalt free, Li1.2(Mn0.32Ni0.32Fe0.16)O2 cathodes for lithium batteries

Cobalt free, eco-friendly layered Li1.2(Mn0.32Ni0.32Fe0.16)O2 compounds were synthesized using the adipic acid assisted sol–gel method. The structure and morphology of the prepared materials were examined by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The XRD results revealed that all of the materials possess a layered α-NaFeO2 structure with R3¯m space group. The TEM images confirmed the presence of carbon on the surface of the synthesized material. Galvanostatic charge/discharge studies demonstrated that the cyclic performance and rate capability of the materials were improved by the presence of carbon and the crystalline nature of the material. Among the synthesized materials, the sample prepared with 1 M adipic acid exhibited not only a high discharge capacity of 160 mAh g−1, but also excellent cycling performance with a capacity retention of over 92% after 25 cycles. In addition, electrochemical impedance spectroscopy (EIS) was used to confirm the improvement in the electronic conductivity and the results are discussed in detail.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Cobalt free, layered cathode Li1.2(Mn0.32Ni0.32Fe0.16)O2 was prepared by sol–gel route. ► Mono-dispersed nanoparticles were obtained during synthesis. ► Improved cell performance was noted while using adipic acid (AA) as chelating agent. ► The half-cell delivered the stable discharge capacity of ∼160 mAh/g for 1 M AA.