Enhancing humidity resistance of nickel-rich layered cathode materials by low water-soluble CaF 2 coating.

A low water-solubility but hydrophilic coating of CaF 2 is demonstrated to be effective in mitigating the susceptibility of nickel-rich cathodes to moisture and even water. The ability of the cathode to resist water erosion is not inherently linked to either hydrophobicity or hydrophilicity, but lies in robust chemical bonding within the protective layer exhibiting low water solubility.