Scalable synthesis of high-purity Ti4N3T MXene via saturated salt solution (S3) etching

Two-dimensional (2D) nitride MXenes are predicted to exhibit exceptional metallic properties and high polarity; however, their synthesis remains challenging. Research has relied on traditional molten salt etching, highlighting the need for a scalable, high-purity approach. Here, we present the first solution-based synthesis of Ti 4 N 3 T x MXene via a novel saturated salt solution (S 3 ) etching technique employing alkali metal salts. By optimizing the sintering process for high-purity Ti 4 AlN 3 MAX and refining the S 3 etching route, we significantly reduced the etch pit density to 1.2 × 10 6 cm -2 and lowered the etch pit formation rate to 4%, yielding high-quality, phase-pure Ti 4 N 3 T x MXene. Our study highlights the critical role of alkali metal ions in selective A-layer removal and demonstrates the impressive electrical conductivity and electromagnetic interference shielding performance of 2D nitride MXene, setting a new benchmark for this underexplored material. These findings pave the way for advancing 2D nitride MXenes and their diverse applications. This work presents a scalable route to high-quality Ti 4 N 3 T x MXene via a mild saturated salt solution (S 3 ) etching method, enabled by the optimized synthesis of phase-pure nitride MAX precursors. By overcoming the limitations of conventional molten salt routes, we report the first intrinsic measurements of Ti 4 N 3 T x ’s metallic conductivity and EMI shielding performance, positioning nitride MXenes as promising candidates for advanced 2D electronic and electromagnetic applications.