材料科学
电解质
离子电导率
快离子导体
电导率
无机化学
氧化物
硫化物
碱金属
兴奋剂
钙钛矿(结构)
烧结
金属
化学工程
物理化学
化学
冶金
电极
有机化学
工程类
光电子学
作者
Shengsheng Fan,Meng Lei,Wei Han,Jiulin Hu,Congling Yin,Tongxiang Liang,Chilin Li
标识
DOI:10.1016/j.ensm.2020.05.030
摘要
High-conductivity solid electrolytes are crucial components for the development of Na-based solid state batteries. However the electrolyte structure prototype and corresponding synthesis method are still lacking. The conventional oxide and sulfide electrolytes are precursor-expensive (e.g. Na2S) or energy-intensive in sintering synthesis (e.g. at 1000 °C). Here, we propose a novel anti-perovskite solid electrolyte of Na-rich fluorinated sulfate (Na3SO4F) benefiting from Mg and Cl co-doping by solid state reaction from low-cost precursors at moderate temperature (500 °C). The tailored dual doping enables an improvement of ionic conductivity by three orders of magnitude close to 10−4 S cm−1 at 60 °C. The creation of Na vacancies (by aliovalent Mg doping) and lattice expansion (by substituting F sites with larger-sized Cl ions) are responsible for the conductivity upgrade. A Na–Sn/Fe [Fe(CN)6]3 solid state battery based on Na2.98Mg0.01SO4F0.95Cl0.05 electrolyte can reversibly run with a first discharge capacity as high as 91.0 mAh g−1 and a reversible capacity preserved at 77.0 mAh g−1. This result paves a way to novel anti-perovskite family of fluorinated sulfates as potential alkali metal ion solid electrolytes beyond already reported A3OX (A = Li or Na, X = heavy halogen or hydrogenide anions) anti-perovskites.
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