Cr-Doped Li-Rich Nickel Cobalt Manganese Oxide as a Positive Electrode Material in Li-Ion Batteries to Enhance Cycling Stability

Li-rich nickel cobalt manganese oxide materials with Cr doping were designed in order to improve the cycling stability of Li-rich cathode materials. Several samples with the chemical formula Li1.171(Ni0.191Co0.099Mn0.539)O2, Li1.148Cr0.008(Ni0.191Co0.099Mn0.539)O2, Li1.112Cr0.019(Ni0.191Co0.099Mn0.539)O2, and Li1.171Cr0.039(Ni0.191Co0.099Mn0.539)O2 labeled, respectively, HE-NCM, Li100–3xCrx-NCM (x = 0.67 and 1.67), and Li100Cr3.33-NCM were synthesized by the Pechini method. The materials were characterized by X-ray and neutron diffraction as well as with scanning electron microscopy (SEM). The Li100Cr3.33-NCM material displays the best mitigation of the potential drop after 100 cycles. After 100 cycles, Li98Cr0.67-NCM, Li95Cr3.33-NCM, and Li100Cr3.33-NCM deliver a stable specific charge higher than 200 mA h/g with high-loaded electrodes. While the Li100–3xCrx-NCM samples still display a significant fading of their average discharge potential, the average discharge potential of Li100Cr3.33-NCM material is better stabilized at a value offering a specific energy superior to 700 W h/kg, thus confirming the advantages of Cr doping.