Surface-stabilization of LMR-NCM by Washing with Aqueous Buffers to Reduce Gassing and Improve Cycle-Life

Li- and Mn-rich battery active materials like Li 1.14 (Ni 0.26 Co 0.14 Mn 0.60 ) 0.86 O 2 (LMR-NCM) are promising cathode (CAMs) for next-generation Li-Ion batteries, as they combine a higher energy density than state-of-the-art at lower cost. However, suffer from high gassing, particularly during formation, voltage capacity fading over their cycle life. While electrolyte additives known to alleviate these issues, it will be shown that surface modification of LMR-NCM CAMs can also reduce gassing formation improve long-term stability. Here, we present detailed analysis water-based post-treatment LMR-NCMs, which not only lowers initial by more 90%, but avoids the issue transition metal dissolution observed with conventionally used washing procedures low ph. We thus utilized buffered solution increase pH into stability window (near/above 7), while providing controlled + /H -exchange is possible unbuffered aqueous solutions pure H O, O/alcohol mixtures, or acids. TGA-MS experiment showed heating -exchanged leads protective (near-)surface spinel layer, full-cell cycling displayed drastic improvement retention.