| dc.description.abstract | Lithium-rich layered lithium nickel manganese cobalt oxide Li1.2Mn0.54Ni0.13Co0.13O2 (LRO) has been recognized as a promising cathode material. Due to its highest energy density, widest voltage window, and excellent operating voltage. Furthermore, as a high-manganese cathode material, it possesses low cost and good environmental compatibility. However, the structural instability of LRO leads to poor cycling performance, capacity decay, limiting the development of lithium-rich materials.
To address these challenges, we propose an innovative approach to synthesize LRO cathode materials from precursors using metal-organic frameworks (MOFs) based on purified terephthalic acid (PTA). In this process, organic ligands serve as templates, facilitating uniform arrangement of metal ions and significantly reducing particle size to prepare cathode materials with high cycling stability and energy density. With Fe doping into the PTA-Mn-Ni-Co precursor. We successfully using XRD, XPS, and TEM confirm the incorporation of Fe into the material structure. In addition, we established a direct correlation between material structural changes and electrochemical performance and observed the microscopic structure of the samples through HR-TEM. Our research reveals detailed structural reorganization of cathode materials during long-term cycles and provides a microscopic mechanism for capacity increase, offering theoretical support for understanding battery material regeneration phenomena. The in-situ generate a Li2CO3 coating layer on the surface of LRO during the MOFs process, protecting the material from degradation reactions with the electrolyte and enhancing Li+ diffusion. Furthermore, by appropriate Fe doping, we control the ratio of Li2MnO3 phase to improve material stability. Among the different Fe doping sample, the Li1.2Mn0.54-xNi0.13Co0.13FexO2 (x=0.03) sample exhibits the best performance, achieving an actual capacity of 250 mAh/g at 0.2 C, and discharge capacity of 189 mAh/g and 179 mAh/g after 200 and 500 cycles at 1 C rate, respectively. Moreover, it maintains capacity of 170 mAh/g and 127 mAh/g at 2 C and 5 C rates, respectively. Compared with LRO from other literature, it reveals that the LRO combined with metal-organic frameworks and Fe doping exhibits significantly greater cycling stability than LRO produced by other processes. | en_US |