美国太平洋西北国家实验室Jie Xiao研究团队发现了单晶富镍阴极的可逆平面滑动和微裂纹。 该研究成果发表在2020年12月11日出版的国际学术期刊《科学》。

高能富镍阴极将在先进的锂电池中发挥关键作用，但它会受到水分敏感性、副反应和气体生成的影响。

单晶富镍阴极通过减少相界和材料表面，在解决多晶阴极面临的挑战具有很大的潜力。然而，尽管单晶富镍阴极的过电位、微观结构和电化学行为之间存在着根本性的联系，但高性能单晶富镍阴极的合成仍然是一个具有挑战性的课题。

在单晶富镍阴极中，研究人员观察到沿（003）晶面的可逆平面滑动和微裂纹。微结构缺陷的可逆形成与晶格中Li原子浓度梯度引起的局部应力有关，这为从合成改性中减轻颗粒断裂提供了线索。

附：英文原文

Title: Reversible planar gliding and microcracking in a single-crystalline Ni-rich cathode

Author: Yujing Bi, Jinhui Tao, Yuqin Wu, Linze Li, Yaobin Xu, Enyuan Hu, Bingbin Wu, Jiangtao Hu, Chongmin Wang, Ji-Guang Zhang, Yue Qi, Jie Xiao

Issue&Volume: 2020/12/11

Abstract: High-energy nickel (Ni)–rich cathode will play a key role in advanced lithium (Li)–ion batteries, but it suffers from moisture sensitivity, side reactions, and gas generation. Single-crystalline Ni-rich cathode has a great potential to address the challenges present in its polycrystalline counterpart by reducing phase boundaries and materials surfaces. However, synthesis of high-performance single-crystalline Ni-rich cathode is very challenging, notwithstanding a fundamental linkage between overpotential, microstructure, and electrochemical behaviors in single-crystalline Ni-rich cathodes. We observe reversible planar gliding and microcracking along the (003) plane in a single-crystalline Ni-rich cathode. The reversible formation of microstructure defects is correlated with the localized stresses induced by a concentration gradient of Li atoms in the lattice, providing clues to mitigate particle fracture from synthesis modifications.

DOI: 10.1126/science.abc3167

Source: https://science.sciencemag.org/content/370/6522/1313