National & Local Joint Engineering Laboratory for New Petrochemical Materials & Fine Utilization of Resources, Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research (Ministry of Education of China), Key Laboratory of the Assembly and Application of Organic Functional Molecules of Hunan Province , Hunan Normal University , Changsha 410081 , People's Republic of China.
Hunan Changyuan Lico, Company, Limited , Changsha 410205 , People's Republic of China.
ACS Appl Mater Interfaces. 2019 Nov 27;11(47):44036-44045. doi: 10.1021/acsami.9b11452. Epub 2019 Nov 18.
Nickel-rich layered oxides are promising cathodes for power batteries owing to their high capacity and low cost. However, during the production, storage, and application of nickel-rich cathodes, especially in case the Ni content exceeds 70%, their surfaces almost inevitably react with ambient air to form electrochemically inert LiCO and LiOH, leading to significant capacity loss and therefore imposing a significant hurdle to practical applications of nickel-rich cathodes. Here, we reveal surface structures and electrochemical properties of the exposed LiNiCoAlO (NCA) cathodes and investigate systematically the impact of exposure humidity, temperature, and time on NCA cathodes. We demonstrate that introduction of a 3.0-4.5 V galvanostatic cycling operation at initial cycles can remarkably regenerate the subsequent 3.0-4.3 V battery performances of the exposed cathode. This work represents a facile method to regenerate the battery performance of surface-degraded nickel-rich cathodes, opening up an avenue in fulfilling efficient production, storage, and application of nickel-rich cathode materials.
富镍层状氧化物由于其高容量和低成本，是用于动力电池的有前途的正极材料。然而，在富镍正极的生产、储存和应用过程中，特别是在 Ni 含量超过 70%的情况下，其表面几乎不可避免地会与环境空气发生反应，形成电化学惰性的 LiCO 和 LiOH，导致容量显著损失，因此对富镍正极的实际应用构成了重大障碍。在这里，我们揭示了暴露的 LiNiCoAlO（NCA）正极的表面结构和电化学性质，并系统地研究了暴露湿度、温度和时间对 NCA 正极的影响。我们证明，在初始循环中引入 3.0-4.5 V 的恒流循环操作可以显著恢复暴露正极后续 3.0-4.3 V 的电池性能。这项工作代表了一种使表面退化的富镍正极电池性能再生的简便方法，为实现富镍正极材料的高效生产、储存和应用开辟了一条途径。
