Platform Technology Lab, Samsung Advanced Institute of Technology, 130 Samsung-ro, Suwon, Gyeonggi-do, 16678, Republic of Korea.
Energy Lab, Samsung Advanced Institute of Technology, 130 Samsung-ro, Suwon, Gyeonggi-do, 16678, Republic of Korea.
Sci Rep. 2017 Aug 2;7(1):7151. doi: 10.1038/s41598-017-07375-6.
Ni-rich layered oxides are promising cathode materials due to their high capacities. However, their synthesis process retains a large amount of Li residue on the surface, which is a main source of gas generation during operation of the battery. In this study, combined with simulation and experiment, we propose the optimal metal phosphate coating materials for removing residual Li from the surface of the Ni-rich layered oxide cathode material LiNiCoMnO. First-principles-based screening process for 16 metal phosphates is performed to identify an ideal coating material that is highly reactive to LiO. By constructing the phase diagram, we obtain the equilibrium phases from the reaction of coating materials and LiO, based on a database using a DFT hybrid functional. Experimental verification for this approach is accomplished with Mn(PO), Co(PO), Fe(PO), and TiPO. The Li-removing capabilities of these materials are comparable to the calculated results. In addition, electrochemical performances up to 50 charge/discharge cycles show that Mn-, Co-, Fe-phosphate materials are superior to an uncoated sample in terms of preventing capacity fading behavior, while TiPO shows poor initial capacity and rapid reduction of capacity during cycling. Finally, Li-containing equilibrium phases examined from XRD analysis are in agreement with the simulation results.
富镍层状氧化物由于其高容量而成为有前途的阴极材料。然而，它们的合成过程在表面保留大量的锂残留物，这是电池运行过程中产生气体的主要来源。在这项研究中，我们结合模拟和实验，提出了用于去除富镍层状氧化物阴极材料 LiNiCoMnO 表面残留锂的最佳金属磷酸盐涂层材料。通过基于第一性原理的筛选过程，对 16 种金属磷酸盐进行筛选，以确定与 LiO 高度反应的理想涂层材料。通过构建相图，我们根据使用 DFT 混合泛函的数据库，从涂层材料和 LiO 的反应中获得平衡相。通过 Mn(PO)、Co(PO)、Fe(PO)和 TiPO 对这种方法进行了实验验证。这些材料的除锂能力与计算结果相当。此外，高达 50 次充放电循环的电化学性能表明，在防止容量衰减方面，Mn、Co、Fe 磷酸盐材料优于未涂层样品，而 TiPO 则表现出初始容量差和循环过程中容量迅速下降的问题。最后，从 XRD 分析中检查的含锂平衡相与模拟结果一致。
