Modification and performance analysis of lithium-ion battery cathode materials by doping with transition metal oxides

Abstract

The increasing global demand for high-performance energy storage systems has intensified research focused on enhancing lithium-ion battery performance through cathode material modification. This study investigates the effects of transition metal oxide doping on the electrochemical behavior of lithium-ion battery cathode materials. Various transition metal oxides including Ta₂O₅, MoO₃, Al₂O₃, TiO₂, and Cr₂O₃ were systematically incorporated into layered lithium nickel manganese cobalt oxide (Li[Ni₀.₈Mn₀.₁Co₀.₁]O₂) cathodes using a modified co-precipitation method followed by calcination under optimized conditions. Physicochemical characterization employing X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy confirmed successful doping and revealed significant microstructural modifications, including refined particle size distribution and enhanced crystallinity. Electrochemical testing demonstrated that 2 mol% Ta⁵⁺-doped cathodes exhibited superior performance, retaining 89,4% capacity after 500 cycles at 1C rate, compared to 67,2% for undoped samples. Mo⁶⁺-doped cathodes showed exceptional rate capability, delivering 78.6% of their nominal capacity at 10C discharge rate. Impedance analysis indicated reduced charge transfer resistance in doped samples, while differential scanning calorimetry confirmed enhanced thermal stability. In-situ diffraction studies revealed that high-valence dopants effectively suppressed detrimental phase transitions and lattice oxygen loss during cycling. The findings demonstrate that strategic transition metal oxide doping represents a promising approach for developing next-generation high-energy lithium-ion batteries with improved cycling stability, rate capability, and safety characteristics.