Mitigating hydrogen gas evolution in high nickel cathodes using single-crystalline NCM particles

Abstract

Hydrogen gas (H₂) evolution in high-nickel lithium nickel cobalt manganese oxide (NCM) cathodes poses significant safety and performance challenges, particularly in cylindrical cell-type lithium-ion batteries (LIBs). This study investigates the use of single-crystal NCM (Ni 96%) cathodes to mitigate H₂ evolution in the early and later stages of full-cell configurations. Utilizing in situ differential electrochemical mass spectrometry and various spectroscopic characterization, we examine the characteristics of cathodes. In the early stage, the reduced surface area of single-crystal NCM cathodes minimizes the formation of carbonate salts and LiOH contaminant species, thereby mitigating H₂ evolution. Furthermore, the exceptional structural stability of the single-crystal NCM particles prevents pulverization during cycling, which in turn reduces nickel dissolution from the NCM cathodes, resulting in suppressing H₂ evolution in a later stage by limiting the formation of metallic catalysts. Thus, single-crystal NCM cathodes offer crucial insights into the design of high-nickel NCM-based batteries with enhanced safety.