Vacancy-Driven Na+ Superionic Conduction in New Ca-Doped Na3PS4 for All-Solid-State Na-Ion Batteries

Chang Ki Moon, Hyun Jae Lee, Kern Ho Park, Hiram Kwak, Jongwook W. Heo, Keunsu Choi, Hyemi Yang, Maeng Suk Kim, Seung Tae Hong, Jun Hee Lee, Yoon Seok Jung

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89 Citations (Scopus)


Mechanically sinterable sulfide Na+ superionic conductors are key to enabling room-temperature-operable all-solid-state Na-ion batteries (ASNBs) for large-scale energy storage applications. To date, few candidates can fulfill the requirement of a high ionic conductivity of ≥1 mS cm-1 using abundant, cost-effective, and nontoxic elements. Herein, the development of a new Na+ superionic conductor, Ca-doped cubic Na3PS4, showing a maximum conductivity of ∼1 mS cm-1 at 25 °C is described. Complementary analyses using conductivity measurement by the AC impedance method, 23Na nuclear magnetic resonance spectroscopy, and density functional theory calculations reveal that the aliovalent substitution of Na+ in Na3PS4 with Ca2+ renders a cubic phase with Na vacancies, which increases the activation barriers but drastically enhances Na-ion diffusion. It is demonstrated that TiS2/Na-Sn ASNBs employing Ca-doped Na3PS4 exhibit a high charge capacity of 200 mA h g-1 at 0.06C, good cycling performance, and higher rate capability than those employing undoped cubic Na3PS4.

Original languageEnglish
Pages (from-to)2504-2512
Number of pages9
JournalACS Energy Letters
Issue number10
Publication statusPublished - 2018 Oct 12

Bibliographical note

Publisher Copyright:
© Copyright 2018 American Chemical Society.

All Science Journal Classification (ASJC) codes

  • Chemistry (miscellaneous)
  • Renewable Energy, Sustainability and the Environment
  • Fuel Technology
  • Energy Engineering and Power Technology
  • Materials Chemistry


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