ABSTRACT
Motivated by the recent experimental synthesis of a LaCl3-based lithium superionic conductor [Yin, Y.-C. Nature 2023, 616, 77-83], we explore the potential of a LaCl3-based system for a sodium superionic conductor in this work. Using density functional theory combined with molecular dynamics simulation and a grand potential phase diagram analysis, we find that the resulting Na3La5Cl18 exhibits high energetic stability with a small energy-above-hull of 18 meV per atom, a large band gap of 5.58 eV, a wide electrochemical window of 0.41-3.76 V from the cathodic to the anodic limit, and a high Na+ conductivity of 1.3 mS/cm at 300 K. Furthermore, Na3La5Cl18 shows high chemical interface stability with the reported high-potential cathode materials such as NaCoO2, NaCrO2, Na2FePO4F, Na3V2(PO4)3, and Na3V2(PO4)2F3. These findings clearly suggest that the LaCl3-based framework can be used as a building block not only for Li-ion but also for Na-ion batteries.
ABSTRACT
Although the electronics and optoelectronics based on two-dimensional (2D) SnS have attracted great interest, their development is hindered by the large contact resistance at the interface of the metal-semiconductor junction. In this work, using first-principles calculations, we evaluate the contact performance in a van der Waals heterostructure composed of 2D SnS and TaS2. We demonstrate that holes can freely transfer from the electrode to the channel as a consequence of the Schottky-barrier-free interface as well as an upward band bending. Moreover, we show that the intrinsic properties of the SnS monolayer are well-preserved in the heterojunction, which is different from those of contact with metal surfaces. An enhanced optical response is also observed as compared with the freestanding sheet. Given the recent experimental synthesis of the SnS-TaS2 superlattice, this study enhances the understanding of the interface properties of SnS-based metal contact, which is essential for future device applications.
