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

초록

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.

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