Platform Technology Lab , Samsung Advanced Institute of Technology , 130 Samsung-ro , Suwon , Gyeonggi-do 16678 , Republic of Korea.
Department of Mechanical Engineering , Gachon University , 1342 Seongnamdaero, Sujeong-gu , Seongnam-si , Gyeonggi-do 13120 , Republic of Korea.
ACS Appl Mater Interfaces. 2018 Jun 20;10(24):20599-20610. doi: 10.1021/acsami.8b05648. Epub 2018 Jun 11.
For developing the industrially feasible Ni-rich layered oxide cathode with extended cycle life, it is necessary to mitigate both the mechanical degradation due to intergranular cracking between primary particles and gas generation from the reaction between the electrolyte and residual Li in the cathode. To simultaneously resolve these two issues, we herein propose a simple but novel method to reinforce the primary particles in LiNiCoMnO by providing a Li-reactive material, whose spinel interphase is coherent with the surface of the cathode. The modified structure significantly outperforms analogous bare samples: they conserve more than 90% of the initial capacity after 50 cycles and also exhibit a greater rate capability. By tracking the same particle location during cycling, we confirmed that the current method significantly reduces crack generation because the provided coating material can penetrate inside the grain boundary of the secondary particle and help maintain the volume of the primary particle. Finally, first-principles calculations were implemented to determine the role of this spinel material, i.e., having intrinsically isotropic lattice parameters, superior mechanical properties, and only a small volume change during delithiation. We believe that the proposed method is straightforward and cost-effective; hence, it is directly applicable for the mass production of Ni-rich cathode material to enable its commercialization.
为了开发具有长循环寿命的工业可行的富镍层状氧化物阴极，有必要缓解由于初级颗粒之间的晶间开裂以及阴极中电解质和残留 Li 之间的反应产生的气体生成所导致的机械降解。为了同时解决这两个问题，我们在此提出了一种简单但新颖的方法，通过提供与阴极表面具有相干性的尖晶石相间层来增强 LiNiCoMnO 中的初级颗粒。改性结构的性能明显优于类似的裸样：它们在 50 次循环后保留了超过初始容量的 90%，并且还表现出更高的倍率性能。通过在循环过程中跟踪相同的颗粒位置，我们证实了该方法可以显著减少裂纹的产生，因为提供的涂层材料可以渗透到二次颗粒的晶界中，并有助于保持初级颗粒的体积。最后，进行了第一性原理计算以确定这种尖晶石材料的作用，即具有固有各向同性的晶格参数、优异的机械性能以及在去锂化过程中仅发生小的体积变化。我们相信，所提出的方法简单且具有成本效益，因此可以直接应用于富镍阴极材料的大规模生产，以实现其商业化。
