Design of high-performance and sustainable Co-free Ni-rich cathodes for next-generation lithium-ion batteries

Great attention has been given to high-performance and inexpensive lithium-ion batteries (LIBs) in response to the ever-increasing demand for the explosive growth of electric vehicles (EVs). High-performance and low-cost Co-free Ni-rich layered cathodes are considered one of the most favorable candidates for next-generation LIBs because the current supply chain of EVs relies heavily on scarce and expensive Co. Herein, we review the recent research progress on Co-free Ni-rich layered cathodes, emphasizing on analyzing the necessity of replacing Co and the popular improvment methods. The current advancements in the design strategies of Co-free Ni-rich layered cathodes are summarized in detail. Despite considerable improvements achieved so far, the main technical challenges contributing to the deterioration of Co-free Ni-rich cathodes such as detrimental phase transitions, crack formation, and severe interfacial side reactions, are difficult to resolve by a single technique. The cooperation of multiple modification strategies is expected to accelerate the industrialization of Co-free Ni-rich layered cathodes, and the corresponding synergistic mechanisms urgently need to be studied. More effects will be aroused to explore high-performance Co-free Ni-rich layered cathodes to promote the sustainable development of LIBs.