Effect of Al and Fe Doping on the Electrochemical Behavior of Li_1.2Ni_0.133Mn_0.534Co_0.133O₂ Li-Rich Cathode Material

This article studies the doping of Li-rich cathode materials. Aluminum and iron were chosen as dopants. Li-rich cathode materials for lithium-ion batteries, which were composed of Li_1.2Ni_0.133Mn_0.534Co_0.133O₂ with a partial replacement of cobalt (2 at %) by iron and aluminum, were synthesized. The dopants were introduced at the precursor synthesis stage by co-precipitation. The presence of Fe and Al in the composition of the synthesized samples was proved by inductively coupled plasma mass spectrometry, X-ray diffraction analysis and X-ray microanalysis. The cathode materials were tested electrochemically. The incorporation of Al and Fe into the structure of lithium-enriched materials improved the cyclability and reduced the voltage fade of the cathodes. An analysis of the electrochemical data showed that the structural changes that occur in the initial cycles are different for the doped and starting materials and affect their cycling stability. The partial cation substitution suppressed the unfavorable phase transition to lower-voltage structures and improved the electrochemical performance of the materials under study.