Fundamental and solutions of microcrack in Ni-rich layered oxide cathode materials of lithium-ion batteries

Ni-rich layered transition metal oxide is one of the most promising cathode materials for the next generation lithium-based automotive batteries due to its excellent electrochemical performances. Nevertheless, its further applications are capped by the structural/interfacial instability during the prolonged charging/discharging, leading to severe performance fading and serious safety concerns. Here, we provide a comprehensive review about challenges and solutions to modify Ni-rich layered cathodes specifically for microcrack failure. Firstly, the mechanism of microcrack formation and evolution are concluded thoroughly. Secondly, recent advances in stabilizing the structure/interface of Ni-rich cathodes are summarized such as surface coating, cation/anion doping, composition tailoring, morphology engineering and electrolytes optimization. Furthermore, strategies to mitigate the microcrack and then boost the electrochemical performance of Ni-rich cathodes at the chemical & mechanical engineering level are presented. More importantly, outlook and perspectives to facilitate the practical application of Ni-rich layered cathodes toward electrical vehicle application are provided as well. The information compiled herein can promote the understanding of the microcracks of Ni-rich cathode materials, including its fundamental science, characterization method, and strategies for designing crack-free Ni-rich cathode materials. Furthermore, we provide a new idea for material modification, which is perspective strategy from crystallographic, structural mechanics and chemistry under the guidance of “chemical-mechanical” effect. • The mechanism of microcrack formation and evolution are concluded. • Recent advances in stabilizing the structure/interface of Ni-rich cathodes are summarized. • Strategies to mitigate the microcrack and then boost the electrochemical performance of Ni-rich cathodes are presented. • Main challenges and the future horizons are outlooked.