context: For more than a decade, researchers have known that layered oxide cathodes, particularly NMC and NCA materials, have fragile surfaces. Thus, it allows various chemical/electrochemical reactions with gases (e.g., storing environments) or liquids (e.g., organic electrolytes) at the surfaces. As the urgent demand for commercialization of the Co-free, Ni-rich layered cathodes, the shelf life of active powders is considered as an important characteristic due to the uncertain delay from powder production to electrode processing and to battery manufacturing. In addition, with the nickel concentration approaching 100%, and the pursuit towards Co-free materials, surface stability against the organic electrolyte is vital in the commercialization. LiNiO2-based materials are more unstable than their cobalt-containing analogs because of the increased magnetic frustration of Ni3+ than Co3+. Therefore, surface degradation is more severe in Ni-rich oxide cathodes due to the high oxidation state of nickel. We previously discovered that the electrochemical performance of LiNiO2 cathode can be improved by incorporating dual dopants through the surface and bulk properties enhancement. Herein, we exploit the platform of LiNiO2-based materials to study the surface fragility under various practical conditions. Moreover, we will further discuss advantages of doping chemistry through the post-mortem characterizations. Lastly, we are aiming to provide insights into developing low-cost, high-energy Co-free Ni-rich cathode materials.
answer: Ni-rich oxide