Conductive TiN network-assisted fast-charging of lithium-ion batteries

Abstract

To reduce the charging time of lithium-ion batteries, we propose a surface-engineering technique for improving the sluggish interfacial reactions of commercial graphite anodes. Titanium nitride (TiN) nanoparticles are integrated onto graphite particles as a functional promoter by using an Mg-assisted nitriding process combined with a molten salt method. Unlike conventional nitriding processes, this synthesis method ensures enhanced safety and efficiency because it does not require the use of ammonia gas. Moreover, the molten-salt method facilitates a uniform and scalable production process. The TiN nanoparticles effectively reduce the interfacial resistance on the graphite surface due to its low Li⁺ adsorption energy (−2.0 eV) and provide excellent electrical conductivity (∼10⁶ S cm⁻¹) during cycling. Furthermore, the partial conversion of TiN nanoparticles leads to the formation of highly conductive Li₃N–TiN clusters, which effectively modify the physicochemical properties of the graphite surface to enhance Li⁺ conduction. Notably, a full-cell configured with a TiN-coated graphite anode exhibits fast-charging performance, reaching 80% of the state of charge within just 16 min. It also maintains a stable cycling performance over 300 cycles under fast-charging conditions (i.e., 3C charging and 1C discharging). The full cell retains a high reversible capacity (93.5%) after 300 cycles, with no evidence of undesirable Li plating on the graphite surface.