Elastic Properties of Alkali Superionic Conductor Electrolytes from First Principles Calculations

Abstract

In this work, we present a comprehensive investigation of the elastic properties (the full elastic tensor, bulk, shear and Young's moduli, and Poisson's ratio) of 23 well-known ceramic alkali superionic conductor electrolytes (SICEs) using first principles calculations. We find that the computed elastic moduli are in good agreement with experimental data (wherever available) and chemical bonding nature. The anion species and structural framework have a significant influence on the elastic properties, and the relative elastic moduli of the various classes of SICEs follow the order thiophosphate < antiperovskite < phosphate < NASICON < garnet < perovskite. Within the same framework structure, we observe that Na SICEs are softer than their Li analogs. We discuss the implications of these findings in the context of fabrication, battery operation, and enabling a Li metal anode. The data computed in this work will also serve as a useful reference for future experiments as well as theoretical modeling of SICEs for rechargeable alkali-ion batteries.

Role of Na+ Interstitials and Dopants in Enhancing the Na+ Conductivity of the Cubic Na3PS4 Superionic Conductor

“…18,19 Recent first-principles work also shows that Na 3 PS 4 is likely to have favorable elastic properties that allow good electrode contact to be achieved with cold-press sintering. 20 c-Na 3 PS 4 is therefore a promising solid electrolyte candidate, particularly if its ionic conductivity is further improved with proper doping strategies. Using first-principles computational methods, one can rapidly investigate the microscopic mechanisms of diffusion in c-Na 3 PS 4 and the effect of doping on its overall conductivity.…”

Room-Temperature All-solid-state Rechargeable Sodium-ion Batteries with a Cl-doped Na3PS4 Superionic Conductor

“…Though it is likely that sulfide and selenide-based solid electrolytes may exhibit lower intrinsic electrochemical stability, the formation of passivating phases at the electrode-solid electrolyte interface can potentially mitigate further reactions212223. Sulfide electrolytes, particularly sodium sulfides, also tend to be softer than oxides24, which allows intimate contact between electrode and solid electrolyte to be achieved via cold pressing instead of high-temperature sintering.…”

Interface‐Engineered Li7La3Zr2O12‐Based Garnet Solid Electrolytes with Suppressed Li‐Dendrite Formation and Enhanced Electrochemical Performance

“…Long‐term testing of an LLZO‐IL/Li symmetrical cell at a current density of 0.1 mA cm −2 at room temperature is shown in Figure d. The voltage polarization is stable at 0.17 V for more than 300 cycles without short circuit. The role of BMP‐TFSI in the HSE is depicted schematically in Figure e. From the mechanical perspective, the “soft” BMP‐TFSI continuous coating layer, which fills the voids and connects the grain boundaries, can easily form intimate contacts with the “rigid” LLZO oxide and maintain good interfacial compatibility toward lithium metal . Therefore, on the one hand, the coating layer can form a compact and stable interlayer to resist the volume strain at the electrolyte/electrode interface and inside the HSE during cycling .…”