This technology is a cathode for lithium secondary batteries featuring a metal-organic framework (MOF) coating on the surface of the cathode active material, with chelating agents embedded to physically block the MOF pores. The coating layer prevents direct contact between the electrolyte and the active material while capturing leached transition metal ions.
In lithium secondary batteries, repeated charge-discharge cycles cause transition metals to leach from the cathode active material into the electrolyte. Direct contact between the active material and the electrolyte leads to degradation caused by side reactions and crosstalk, resulting in a rapid decline in discharge capacity over time.
This technology introduces chelating agents, such as EDTA, into the pores of carboxyl-functionalized MOFs (e.g., MOF-808) at a weight ratio of 1:0.3 to 1:15. This coating is applied thinly to NCM-based cathode active materials at 0.1 to 0.4 parts by weight per 100 parts of active material to capture transition metals and lower the desolvation energy of lithium ions. This coating ensures stable discharge capacity for over 100 cycles. Applicable to high-nickel NCM cathodes for EVs, long-life cells for ESS, and surface treatment processes, it uses less than 1 wt% of coating to suppress transition metal leaching and electrolyte side reactions, significantly improving long-term cycle capacity retention.
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