TY - JOUR
T1 - Origin of Outstanding Phase and Moisture Stability in a Na3P1-xAsxS4 Superionic Conductor
AU - Shang, Shun Li
AU - Yu, Zhaoxin
AU - Wang, Yi
AU - Wang, Donghai
AU - Liu, Zi Kui
N1 - Publisher Copyright:
© 2017 American Chemical Society.
PY - 2017/5/17
Y1 - 2017/5/17
N2 - Sodium ion (Na) solid-state electrolytes (SSEs) are critical to address notorious safety issues associated with liquid electrolytes used in the current Na ion batteries. Fulfilling multiple innovations is a grand challenge but is imperative for advanced Na ion SSEs, such as a combination of high ionic conductivity and excellent chemical stability. Here, our first-principles and phonon calculations reveal that Na3P1-xAsxS4 (0 ≤ x ≤ 1) is a solid-state superionic conductor stabilized at 0 K by zero-point vibrational energy and at finite temperatures by vibrational and configurational entropies. Especially, our integrated first-principles and experimental approach indicates that Na3P1-xAsxS4 is dry-air stable. Additionally, the alloying element arsenic greatly enhances the moisture (i.e., H2O) stability of Na3P1-xAsxS4 by shifting the reaction products from the easy-forming oxysulfides (such as Na3POS3 and Na3PO2S2 with H2S release) to the difficult-forming hydrates (such as Na3P1-xAsxS4·nH2O with n = 8 and/or 9) due mainly to a weaker As-O affinity compared to that of P-O. The present work demonstrates that alloying is able to achieve multiple innovations for solid-state electrolytes, such as a desirable superionic conductor with not only a high ionic conductivity (for example, 1.46 mS/cm at room temperature achieved in Na3P0.62As0.38S4) but also an excellent chemical stability with respect to temperature, composition, and moisture.
AB - Sodium ion (Na) solid-state electrolytes (SSEs) are critical to address notorious safety issues associated with liquid electrolytes used in the current Na ion batteries. Fulfilling multiple innovations is a grand challenge but is imperative for advanced Na ion SSEs, such as a combination of high ionic conductivity and excellent chemical stability. Here, our first-principles and phonon calculations reveal that Na3P1-xAsxS4 (0 ≤ x ≤ 1) is a solid-state superionic conductor stabilized at 0 K by zero-point vibrational energy and at finite temperatures by vibrational and configurational entropies. Especially, our integrated first-principles and experimental approach indicates that Na3P1-xAsxS4 is dry-air stable. Additionally, the alloying element arsenic greatly enhances the moisture (i.e., H2O) stability of Na3P1-xAsxS4 by shifting the reaction products from the easy-forming oxysulfides (such as Na3POS3 and Na3PO2S2 with H2S release) to the difficult-forming hydrates (such as Na3P1-xAsxS4·nH2O with n = 8 and/or 9) due mainly to a weaker As-O affinity compared to that of P-O. The present work demonstrates that alloying is able to achieve multiple innovations for solid-state electrolytes, such as a desirable superionic conductor with not only a high ionic conductivity (for example, 1.46 mS/cm at room temperature achieved in Na3P0.62As0.38S4) but also an excellent chemical stability with respect to temperature, composition, and moisture.
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U2 - 10.1021/acsami.7b03606
DO - 10.1021/acsami.7b03606
M3 - Article
C2 - 28453260
AN - SCOPUS:85019416338
SN - 1944-8244
VL - 9
SP - 16261
EP - 16269
JO - ACS Applied Materials and Interfaces
JF - ACS Applied Materials and Interfaces
IS - 19
ER -