First-Principles Studies on Ultrafast Ionic Transport through van der Waals Solid Electrolytes of YX3 (X = Cl, Br, I) with Quasi-One-Dimensional Atomic Pore Channels

Solid electrolytes with intrinsic ionic transport channels are expected to achieve ultrafast ionic transport and improve ionic conductivity. Herein, a series of novel van der Waals (vdW) materials YX3 (X = Cl, Br, I) with quasi-one-dimensional (quasi-1D) atomic pore channels have been investigated for transport of Li+, Na+, and K+ ions by adopting first-principles calculations. The results indicate that the intrinsic YX3 systems are dynamically stable based on phonon spectra and YX3-ion complexes are energetically stable through examining the binding interactions. Moreover, the energy barriers of ionic transport through YX3 are in the range 0.004-0.020 eV within the 1D atomic pore channels, which are much smaller than those of conventional solid electrolytes, implying the ultrafast ionic transport in the time scale of subpicoseconds. Meanwhile, the insulating characteristics of YX3 systems are well maintained during the ionic transport process. Besides, YX3 systems show better interface stability in contact with Li, Na, and K metal electrodes compared with conventional solid electrolytes. These results provide theoretical guidance for vdW materials of YX3 applications in energy storage devices as promising solid electrolyte candidates.