Unique insights into the design of low-strain single-crystalline Ni-rich cathodes with superior cycling stability
Qiang Han, Haifeng Yu, Lele Cai, Ling Chen, Chunzhong Li, Hao Jiang
Abstract
Micro-sized single-crystalline Ni-rich cathodes are emerging as prominent candidates owing to their larger compact density and higher safety compared with poly-crystalline counterparts, yet the uneven stress distribution and lattice oxygen loss result in the intragranular crack generation and planar gliding. Herein, taking LiNi 0.83 Co 0.12 Mn 0.05 O 2 as an example, an optimal particle size of 3.7 µm is predicted by simulating the stress distributions at various states of charge and their relationship with fracture free-energy, and then, the fitted curves of particle size with calcination temperature and time are further built, which guides the successful synthesis of target-sized particles ( m -NCM83) with highly ordered layered structure by a unique high-temperature short-duration pulse lithiation strategy. The m -NCM83 significantly reduces strain energy, Li/O loss, and cationic mixing, thereby inhibiting crack formation, planar gliding, and surface degradation. Accordingly, the m-NCM83 exhibits superior cycling stability with highly structural integrity and dual-doped m-NCM83 further shows excellent 88.1% capacity retention.