Single Layer Dititanium Oxide Ti2O MOene: Multifunctional Promises for Electride, Anode Materials, and Superconductor.
Using the first principles calculations, we report the existence of the single layer (SL) dititanium oxide Ti2O (labeled as MOene) that constructs a novel family of MXene based on transition metal oxides. This MOene material strongly contrasts the conventional ones consisting of transition metal carbides and/or nitrides. SL Ti2O has high thermal and dynamical stabilities because of the strong Ti O ionic bonding interactions. Moreover, this material is an intrinsic electride and exhibits extremely low diffusion barriers of ~12.0 and 6.3 meV for Li and Na diffusion, respectively. When applied as anode materials in lithium ion batteries and sodium ion batteries, it possesses a high energy storage capacity (960.23 mAhg 1) surpassing the traditional MXenes based anodes. The superb electrochemical performance stems from the existing anionic electron on Ti2O surface. Astonishingly, SL Ti2O is also determined to be a superconductor with a superconducting transition temperature (Tc) of ~9.8 K, which originates from the soft mode of the first acoustic phonon branch and enhanced electron phonon coupling in the low frequency region. Furthermore, this soft mode behaves much softer upon applying a compressive strain of 2% leading to a higher Tc of 11.9 K. Our finding broadens the family of MXenes and could facilitate more experimental efforts toward future nanodevices.
The journal of physical chemistry letters