Synthesis of new<scp>two‐dimensional</scp>titanium carbonitride<scp>Ti₂C₀</scp>_.<scp>₅N₀</scp>_.5T_<i>x</i><scp>MXene</scp>and its performance as an electrode material for<scp>sodium‐ion</scp>battery

Two-dimensional (2D) layered transition metal carbides/nitrides, called MXenes, are attractive alternative electrode materials for electrochemical energy storage. Owing to their metallic electrical conductivity and low ion diffusion barrier, MXenes promising anode sodium-ion batteries (SIBs). Herein, we report on a new 2D carbonitride MXene, viz., Ti2C0.5N0.5Tx (Tx stands surface terminations), the only second after Ti3CNTx so far. A type of in situ HF (HCl/KF) etching condition was employed synthesize multilayer powders from Ti2AlC0.5N0.5. Spontaneous intercalation tetramethylammonium followed by sonication water allowed large-scale delamination this titanium into sheets. Multilayer showed higher specific capacities larger electroactive area than those Ti2CTx powders. show capacity 182 mAh g−1 at 20 mA g−1, highest among all reported MXene electrodes as SIBs with excellent cycling stability.