Enabling Electrochemical–Mechanical Robustness of Ultra‐High Ni Cathode via Self‐Supported Primary‐Grain‐Alignment Strategy

Abstract

Abstract The electrochemical–mechanical degradation of ultrahigh Ni cathode for lithium‐ion batteries is a crucial aspect that limits the cycle life and safety of devices. Herein, the study reports a facile strategy involving rational design of primary grain crystallographic orientation within polycrystalline cathode, which well enhanced its electro‐mechanical strength and Li+ transfer kinetics. Ex situ and in situ experiments/simulations including cross‐sectional particle electron backscatter diffraction (EBSD), single‐particle micro‐compression, thermogravimetric analysis combined with mass spectrometry (TGA‐MS), and finite element modeling reveal that, the primary‐grain‐alignment strategy effectively mitigates the particle pulverization, lattice oxygen release thereby enhances battery cycle life and safety. Besides the preexisting doping and coating methodologies to improve the stability of Ni‐rich cathode, the primary‐grain‐alignment strategy, with no foreign elements or heterophase layers, is unprecedently proposed here. The results shed new light on the study of electrochemical–mechanical strain alleviation for electrode materials.

Keywords

• cathode designs
• electrochemical–mechanical properties
• Ni‐rich cathodes
• Lithium ion batteries