To reduce the cost and enhance the energy density of lithium-ion batteries (LIBs), enabling electric vehicles (EVs) to achieve long ranges and compete cost-effectively with vehicles with internal combustion engines, developing nickel-rich/cobalt-poor layered cathode (LiNi_1−x−yMn_yCo_xO₂, x + y ≤ 0.2) is one of the most current effective strategies. In fact, to increase the capacity (> 200 mAh.g^-1) a high Ni content is required while to impact the battery cost a low Co content is favorable. Hence, the development of new compositions for the positive electrode with less cobalt content becomes essential to provide alternative options. This study is a follow of our previous investigation of low cobalt NMC cathode material, a systematic approach was adopted to synthesize two Ni-rich/Co-poor cathode materials, namely LiNi_0.8Mn_0.19Co_0.01O₂ (NMC-1 %) and LiNi_0.8Mn_0.17Co_0.03O₂ (NMC-3 %) via the co-precipitation method, utilizing a continuous stirred tank reactor. The structure, morphology, and electrochemical properties at 0.1 C, 0.2 C, and 0.5 C current rate, of NMC-1 % and NMC-3 % cathodes were investigated and compared. Furthermore, to assess the structural evolution throughout the de-intercalation/intercalation of Li⁺ ions in both materials, operando diffraction of synchrotron radiations was employed as powerful tool for understanding the first lithiation/ de-lithiation mechanism. Both NMC-1 % and NMC-3 % cathodes demonstrate distinct electrochemical performances. At 0.1 C, their initial specific discharge capacities are 178 mAh.g^-1 and 180 mAh.g^-1, respectively; at 0.2 C, 169 mAh.g^-1 and 171 mAh.g^-1; and at 0.5 C, 138 mAh.g^-1 and 156 mAh.g^-1. When compared with NMC-10 % from our previous study, NMC-1 % achieves comparable capacity retention at these rates, highlighting its performance consistency. Moreover, both materials exhibit distinct mechanisms upon the delithiation/lithiation process.

中文翻译：

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在不改变能量性能的情况下，最大限度地降低 LiNi0.8Mn0.1Co0.1O2 正极材料中的钴含量


为了降低成本并提高锂离子电池 （LIB） 的能量密度，使电动汽车 （EV） 能够实现长续航里程并与内燃机汽车竞争，开发富镍/贫钴多层阴极 （LiNi _{1− x − y} Mn _y Co _x O ₂ ， x + y ≤ 0.2） 是当前最有效的策略之一。事实上，为了增加容量 （> 200 mAh.g ^-1 ），需要高 Ni 含量，而为了影响电池成本，低 Co 含量是有利的。因此，为钴含量较低的正极开发新的成分对于提供替代选择变得至关重要。本研究是我们之前对低钴 NMC 正极材料研究的后续，采用系统的方法通过共沉淀法合成了两种富镍/贫钴正极材料，即 LiNi _0.8 Mn _0.19 Co _0.01 O ₂ （NMC-1 %） 和 LiNi _0.8 Mn _0.17 Co _0.03 O ₂ （NMC-3 %），利用连续搅拌釜式反应器。研究并比较了 NMC-1 % 和 NMC-3 % 阴极在 0.1 C、0.2 C 和 0.5 C 电流倍率下的结构、形态和电化学性能。此外，为了评估两种材料中锂 ⁺ 离子脱嵌/插层过程中的结构演变，同步辐射的原位衍射被用作理解第一个锂化/脱锂机制的有力工具。NMC-1 % 和 NMC-3 % 阴极均表现出不同的电化学性能。在 0.1 C 时，它们的初始比放电容量分别为 178 mAh.g ^-1 和 180 mAh.g ^-1 ;在 0.2 °C 时，169 毫安时。g ^-1 和 171 mAh.g ^-1 ;在 0.5 C 时，138 mAh.g ^-1 和 156 mAh.g ^-1 。与我们之前研究的 NMC-10 % 相比，NMC-1 % 在这些速率下实现了相当的容量保持率，凸显了其性能的一致性。此外，这两种材料在脱锂/锂化过程中表现出不同的机制。