Structural manipulation approaches towards enhanced sodium ionic conductivity in Na-rich antiperovskites

JOURNAL OF POWER SOURCES

卷:293

Article

Wang, Yonggang^1,2,3  Wang, Qingfei¹  Liu, Zhenpu¹  Zhou, Zhengyang²  Li, Shuai³  Zhu, Jinlong³  Zou, Ruqiang¹  Wang, Yingxia²  Lin, Jianhua² 

[1] Peking Univ, Coll Engn, Beijing 100871, Peoples R China

[2] Peking Univ, Coll Chem & Mol Engn, State Key Lab Rare Earth Mat Chem & Applicat, Beijing 100871, Peoples R China

[3] Univ Nevada, Dept Phys & Astron, Las Vegas, NV 89154 USA

关键词: Antiperovskite;    Solid electrolyte;    Sodium ionic conductor;    Superionic;   

DOI  :  10.1016/j.jpowsour.2015.06.002

来源: Elsevier

【 摘 要 】

High-performance solid electrolytes are critical for realizing all-solid-state batteries with enhanced safety and cycling efficiency. However, currently available candidates (sulfides and the NASICON-type ceramics) still suffer from drawbacks such as inflammability, high-cost and unfavorable machinability. Here we present the structural manipulation approaches to improve the sodium ionic conductivity in a series of affordable Na-rich antiperovskites. Experimentally, the whole solid solutions of Na3OX (X = Cl, Br, I) are synthesized via a facile and timesaving route from the cheapest raw materials (Na, NaOH and NaX). The materials are nonflammable, suitable for thermoplastic processing due to low melting temperatures (<300 degrees C) without decomposing. Notably, owing to the flexibility of perovskite-type structure, it's feasible to control the local structure features by means of size-mismatch substitution and unequivalent-doping for a favorable sodium ionic diffusion pathway. Enhancement of sodium ionic conductivity by 2 magnitudes is demonstrated by these chemical tuning methods. The optimized sodium ionic conductivity in Na2.9Sr0.05OBr0.6I0.4 bulk samples reaches 1.9 x 10(-3) S/cm at 200 degrees C and even higher at elevated temperature. We believe further chemical tuning efforts on Na-rich antiperovskites will promote their performance greatly for practical all-solid state battery applications. (C) 2015 Elsevier B.V. All rights reserved.

【 授权许可】

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