Recent Advances in nickel-rich Co-free layered cathode materials for lithium-ion batteriesA mini-review

The increasing use of electric vehicles (EVs) based on lithium-ion batteries and the need to access cheap and stable raw materials have directed research programs toward layered oxide cathodes in recent years. Most of the cathodes used in this generation of EVs have cobalt elements. These cathodes suffer from the problem of safety and low driving range. In addition, the high toxicity and unstable supply sources and the predicted shortage of cobalt have hampered the use of these cathodes. The key to solving these problems is to increase the nickel content while reducing or eliminating cobalt. In this article, an attempt has been made to organize and summarize the latest nickel-rich cobalt-free cathodes, including NMA, NFA, and NZA, along with the introduction of doped elements, synthesis methods, advantages, and challenges, including the description of the crystal structure (destruction of the network structure caused by Ni۲+/Li+ cation mixing), charge/discharge capacities, cycle life, mechanical degradation (cracking), surface chemical instability caused by chemical reactions (Li۲Co۳ formation and electrolyte oxidation caused by Ni۳+/۴+) and phase transitions. Common problems should be identified and among the priorities, research should be done in the future to lead to sustainable production and development of nickel-rich Co-free cathodes