Sodium ionic conductivity and stability of amorphous Na2O·2SiO2 added with MxOy (M = Zr, Y, and Sm). (5th April 2018)

• Record Type: Journal Article
• Authors: Zhang, Shan-Lin; Wang, Xiao-Na; Li, Cheng-Xin; Li, Chang-Jiu
• Is Part Of: Materials & design. Volume 143(2018)
• Page Start: 104
• Page End: 111
• Publication Date: 2018-04-05
• Subjects: Ionic conductor -- Amorphous Na2O·2SiO2 -- Oxide adding -- Conductivity -- Thermal stability; Materials -- Periodicals; Engineering design -- Periodicals; Matériaux -- Périodiques; Conception technique -- Périodiques; Electronic journals; 620.11
• DOI: 10.1016/j.matdes.2018.01.041
• Languages: English
• ISSNs: 0264-1275

Abstract

Abstract: Amorphous Na2 O·2SiO2 (A-Na2 O·2SiO2 ) is one of the promising sodium ionic conductors for solid-state sodium-ion battery electrolytes owing to its easy preparation and low production cost. However, Na2 O·2SiO2 glass suffers from relatively low conductivity and poor thermal stability as a result of crystallization and other defects. Herein, we improved the ionic conductivity and thermal stability of A-Na2 O·2SiO2 by adding this material with metal oxides (Mx Oy, M = Y, Sm, and Zr) at varying loadings. The physical properties and stability of the A-Na2 O·2SiO2 added with different oxides were systematically investigated. The results indicated that oxide adding on A-Na2 O·2SiO2 resulted in larger density values that increased with the adding content. Additionally, oxide adding changed the strength of the SiO bond in A-Na2 O·2SiO2, thereby affecting the overall network structure and uniformity. Among the different oxides prepared, added with 3 mol% Sm2 O3, 3 mol% Y2 O3, and 2 mol% ZrO2 showed maximum hardness and elasticity modulus values. Additionally, oxide adding on A-Na2 O·2SiO2 resulted in significantly improved ionic conductivity values. 3 mol% Y2 O3 -added A-Na2 O·2SiO2 material showed the highest ionic conductivity value (5.2 × 10 −3 S cm −1 ) and optimum thermal stability, indicating that Y2 O3 -added Na2 O·2SiO2 has high potential to be high-performance and stable sodium ionic conductors. Graphical abstract: Highlights: Oxides adding can change the network structure and physical properties of A-Na2 O·2SiO2 significantly. The ionic conductivity of A-Na2 O·2SiO2 increased ~5 times by adding 3 mol% Y2 O3 . The conductivity of 3 mol% Y2 O3 -added A-Na2 O·2SiO2 at 400 °C almost not changed after 500 h annealing Conductivity degradation of A-Na2 O·2SiO2 can be attributed to the crystallization.