Enhanced Cycle Performance and Thermal Safety of High Nickel Ternary Batteries Through TiO2/TiN Synergistic Coupling

In this study, a cost-effective ternary soft-pack cell with high nickel content was developed. This involved the uniform dispersion of TiO2 and TiN nanoparticles into the cathode slurry during pulping. TiO2 serves as an interface sacrificial protective agent, reacting with HF generated in the electrolyte to reduce the dissolution of transition metals and slow down the microcracks of positive particles during cycling. TiN, on the other hand, acts as an interfacial soaking agent, contributing to the high thermal conductivity/conductivity of the battery and reducing the uneven temperature rise. These two agents work synergistically to maintain the integrity of particles and prevent the fracture and spalling of the main particles. The addition of TiN effectively disperses and homogenizes the thermal effect caused by the lithium ion intercalation process of the soft-pack full battery. Additionally, the interfacial CEI film at the positive phase boundary is stabilized, which significantly improves the cycle retention and cycle life in electrochemical performance. Therefore, the inclusion of TiO2/TiN enhances the cycle performance and thermal safety of high nickel ternary batteries at high rates and temperatures.