Integrated Lithium-Rich yLi2MnO3∙(1-y)LiNi1/3Co1/3Mn1/3O2 Layered Cathode Nanomaterials for Lithium-Ion Batteries

Integrated Li- and Mn-rich layered cathodes <i>y</i>Li₂MnO₃∙(1-<i>y</i>)Li<i>M</i>O₂ (<i>M</i> = Mn, Co, and Ni) have shown their ability to deliver specific capacities close to 300 mAh g^-1, but their significant drawbacks are capacity fading and voltage decay during cycling. In this study, new stoichiometric high-voltage Li-rich oxides with <i>y</i> = 0.0, 0.3, and 0.5 are synthesized in identical conditions using a sol-gel method. These compositions were analyzed to determine their optimal configuration and to understand their extraordinary behavior. Their nanostructural properties were investigated using XRD and Raman spectroscopy, while the morphology and grain-size distribution of the samples were characterized by BET, SEM and HRTEM analyses. The electrochemical performances of the integrated Li- and Mn-rich compounds were evaluated through galvanostatic cycling and electrochemical impedance spectroscopy. The best cathode material 0.5Li₂MnO₃∙0.5LiNi_1/3Co_1/3Mn_1/3O₂ had a capacity retention of 83.6% after 100 cycles in the potential range 2.0-4.8 V vs. Li⁺/Li.