Achieving High‐Temperature Stability of Metastable α‐MoC1‐x by Suppressing Phase Transformation with Mounted Atoms for Lithium Storage Performance.

Despite a significant advancement in preparing metastable materials, one common problem is the strict and precious reaction conditions due to their metastable structures. Herein, we achieved the preparation of high‐temperature stabilized metastable α‐MoC1−x by mounting zinc atoms into its lattice structure. Such a structural construction could suppress the phase transformation from α‐MoC1−x to β‐Mo2C through restricting the displacement of Mo atoms upon increased temperature. The resultant metastable α‐MoC1−x can be stabilized up to 1000 °C and this stability temperature is the highest for the metastable α‐MoC1−x so far. Synchrotron X‐ray absorption spectroscopy (XAS) and X‐ray photoelectron spectroscopy (XPS) confirm the structure of Zn‐mounted α‐MoC1−x. Density functional theory (DFT) calculations reveal that the introduction of the Zn atoms in the lattice structure of α‐MoC1−x could significantly decrease the energy difference (ΔE) between α‐MoC1−x and β‐Mo2C, thus effectively suppressing the phase transformation from α‐MoC1−x to β‐Mo2C and accordingly maintaining the high‐temperature stability of α‐MoC1−x. This novel strategy can be used as a universal method to be extended to synthesize metastable α‐MoC1−x from different precursors or other mounted elements. Moreover, the optimal product exhibits excellent lithium storage performances in terms of the cycling stability and rate performance. [ABSTRACT FROM AUTHOR]