Stabilizing Interfacial Behaviors of Ni‐rich Cathodes by Upcycling of Oyster Shells Waste

Abstract Layered lithium oxides (LNCM), with over 60% Ni, are promising cathode materials for electric vehicles due to their high capacity. however, reliable cycling retention cannot easily achieved owing to the instability of the interface. Here, recycled oyster shell (OS) is employed as an efficient precursor for the surface modification of LNCM cathodes; subsequently, Ca‐based artificial cathode–electrolyte interphases (CEI) are obtained at the LNCM interfaces through a simple calcination process. When the pulverized OS is calcined with LNCM cathode materials at elevated temperatures, CaCO₃ is converted to CaO via thermal decomposition at the LNCM interface, which effectively protects the unstable interface. Microscopic analyses indicate the nanodomain island‐type CEI layers embedded after OS calcination. The OS‐coated LNCM cathode materials increase the cycling retention after 100 cycles (93.8% vs. 62.7%) and decrease the internal cell pressure by preventing electrolyte decomposition. Incorporating Ca into the LNCM cathode materials also inhibits microcrack formation because of the improvement in particle hardness and the remarkable decrease in the irreversible dissolution of transition metals from LNCM cathodes, considering that Ca plays a crucial role in scavenging fluoride species. Consequently, recycling OS as a functional LNCM precursor is an innovative approach for enhanced cycling retention.