Lithium rich layered oxides (LRLOs) are one of the best alternatives for the next generation positive electrodes materials for Li-ion batteries. However, LRLOs suffer a remarkable voltage decay upon cycling that prevents stable and prolonged electrochemical performances and contains large quantities of cobalt in the transition metal blend. Here, we demonstrate the performance in batteries of a series of innovative materials with general formula Li_1.2+xMn_0.54Ni_0.13Co_0.13-x-yAl_yO₂ (where 0.03≤x ≤ 0.08 and 0.03≤y ≤ 0.05) capable to supply large reversible specific capacities (around 200 mAh g⁻¹), stable cycling performance with reduced voltage decay. This communication sheds light on the interplay between structural and electronic disorder induced by Al/Li co-doping in LRLO and the corresponding functional properties in batteries. The impact of substitution of cobalt by Li and Al co-doping on the structural and morphological properties has been examined by Synchrotron X-ray diffraction (XRD), microwave plasma atomic emission spectrometer (MP-AES) and scanning electron microscopy (SEM). Furthermore, to better understand the structure-function interplay of these over-lithiated materials, ex situ analyses are here reported coupling Synchrotron X-Ray diffraction and Raman Spectroscopy. Based on the obtained results, we proved that coupling the over-lithiation with the aluminum doping, is an effective strategy to reduce the cobalt content into the LRLOs structure maintaining high electrochemical performance. Beside the values of specific capacities obtained in lithium cells, these materials exhibit excellent capacity retention and voltage retention, in particular for the material with the smallest content of cobalt, i.e. Li_1.28Mn_0.54Ni_0.13Co_0.02Al_0.03O₂. Furthermore, thanks to the ex-situ analysis of the latter, we explained the structural evolution of the sample upon cycling that showed the formation of a secondary trigonal phase and the occurrence of limited local distortions of layered structure.

富锂层状氧化物 (LRLO) 是下一代锂离子电池正极材料的最佳替代品之一。然而，LRLO 在循环过程中会遭受显着的电压衰减，这会阻止稳定和延长的电化学性能，并且在过渡金属混合物中含有大量的钴。在这里，我们展示了一系列具有通式 Li _1.2+x Mn _0.54 Ni _0.13 Co _0.13-xy Al _y O ₂（其中 0.03≤ x  ≤ 0.08 和 0.03≤ y  ≤ 0.05）能够供应的创新材料在电池中的性能大的可逆比容量（约 200 mAh g ^-1），稳定的循环性能和降低的电压衰减。这种交流揭示了 LRLO 中 Al/Li 共掺杂引起的结构和电子无序与电池中相应的功能特性之间的相互作用。通过同步加速器 X 射线衍射 (XRD)、微波等离子体原子发射光谱仪 (MP-AES) 和扫描电子显微镜 (SEM) 研究了锂和铝共掺杂取代钴对结构和形态性质的影响。此外，为了更好地了解这些过度锂化材料的结构-功能相互作用，本文报道了将同步加速器 X 射线衍射和拉曼光谱耦合在一起的异位分析。基于所获得的结果，我们证明了过度锂化与铝掺杂的耦合，是减少钴含量进入 LRLO 结构以保持高电化学性能的有效策略。除了在锂电池中获得的比容量值外，这些材料还表现出优异的容量保持率和电压保持率，特别是对于钴含量最低的材料，即 Li_1.28锰_0.54镍_0.13钴_0.02铝_0.03 O ₂。此外，由于后者的异位分析，我们解释了样品在循环过程中的结构演变，表明形成了二次三角相，并发生了有限的层状结构局部变形。