Pacific Northwest National Laboratory, Richland, WA 99352, USA.
School of Engineering, Brown University, Providence, RI 02912, USA.
Science. 2020 Dec 11;370(6522):1313-1317. doi: 10.1126/science.abc3167.
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.
高能量密度的镍（Ni）富正极在先进的锂离子（Li）电池中起着关键作用，但它存在对湿气敏感、副反应和气体生成等问题。单晶 Ni 富正极通过减少相界和材料表面，可以很好地解决多晶 Ni 富正极存在的问题。然而，尽管单晶 Ni 富正极的过电势、微观结构和电化学行为之间存在着根本联系，但合成高性能单晶 Ni 富正极仍然极具挑战性。我们在单晶 Ni 富正极中观察到沿着（003）面的可逆平面滑移和微裂纹。微观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，为通过合成改性减轻颗粒断裂提供了线索。
