Enabling Enhanced Cycling Stability of a LiNi0.8Co0.15Al0.05O2 Cathode by Constructing a Ti-Rich Surface

Herein, we construct a Ti-rich interface of a LiNi0.8Co0.15Al0.05O2 (NCA) secondary particle using titanium nitride (TiN) nanopowders as a dopant to reduce interfacial reaction. Results show that Ti ions integrate into the layered lattice during the dissociation of Ti-N and was enriched within the surface layer. The solid Ti-O bonding effectively enhances the interface stability and reduces lattice change toward an improved cycle stability. As a result, continuous growth of CEI film and dissolution of transition metal elements were depressed. Both thinner cathode-electrolyte interphases (CEI) and phase transition layers form on the surface of particles after a long cycle. The Ti-doping NCA cathode (NCATiN) provides a better capacity retention of 90.9% over 200 cycles.