The competitive ionic conductivities in functional composite electrolytes based on the series of M-NLCO (M = Ge_(0.8)Sm_(0.2)O_(2-δ), Ge_(0.8)Gd_(0.2)O_(2-δ), Ge_(0.8)Y_(0.2)O_(2-δ);NLCO = 0.53Li_2CO3-0.47Na_2CO_3)

摘要

In order to identify competitive ion-conducting materials in ceria-carbonates composite electrolytes, M-NLCO (M = Ge_(0.8)Sm_(0.2)O_(2-δ), Ge_(0.8)Gd_(0.2)O_(2-δ), Ge_(0.8)Y_(0.2)O_(2-δ) (YDC); NLCO = 0.53Li_2CO_3-0.47Na_2CO_3) sintered at different temperatures (600° G, 625° G, 650° G, 675° G and 700° G) have been prepared and characterized. It is found that independent of systems, the 675° G-sintered composites in M-NLCO always present the highest conductivities because of the best NLCO distribution and interfacial microstructures. Moreover, among three composites (sintered at 675° C), the total (σ_t) and grain boundary (σ_(gb)) conductivities measured at 600° C are ranked as: SDC-NLCO (σ_(t-SDC-NLCO)~(600'c) = 9.1× 10~(-2)Scm~(-1) σ_(gb-sdc-nlco)~600'C= 28.1 × 10~(-2)Scm~(-1) , GDC-NLCO (σ_(t-SDC-NLCO)~(600'c) = 5.8 × 10~(-2)Scm~(-1). σ_(gb-sdc-nlco)~600'C = 18.9 × 10~(-2)Scm~(-1)) > YDC-NLCO (σ_(t-SDC-NLCO)~(600'c) = 3.1 × 10~(-2)Scm~(-1). σ_(gb-sdc-nlco)~600'C = 12.6 ×10~(-2) Scm~(-1)), which is attributed to ionic-radius compatibility between the dopant and the host as well as the NLCO distribution and interfacial microstructures. It can be concluded that ionic-radius compatibility between the dopant and the host, NLCO distribution and interfacial microstructures have important effects on improving ionic conductivities for ceria-carbonates composite electrolytes.