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A strategy of regulating the basicity of perovskite oxygen ions by cation doping is proposed to design cathode materials with high catalytic activity for solid oxide electrolysis cells (SOECs). Specifically, a series of Sr 2 Fe 1.5- x Zr x Mo 0.5 O 6−δ (SFZ x M) perovskites are developed and characterized for its electrocatalytic activity and oxygen ions basicity to investigate the effect on electrochemical performance. The experimental results show that the single cell prepared with the Sr 2 Fe 1.3 Zr 0.2 Mo 0.5 O 6−δ (SFZ2M) cathode reaches a current density of 1.85 A cm−2 at 1.8 V and 800 °C and exhibits good stability over 120 h under CO 2 atmosphere. Combined with first-principles calculations, it is further confirmed that the introduction of low-electronegativity ions can improve the oxygen ions basicity and also increase the oxygen vacancy concentration of the cathode, thereby realizing the improvement of electrochemical performance. Thus, this strategy provides new insights into designing electrodes for direct CO 2 electrolysis as well as other electrochemical catalysis. [Display omitted] • Zr-doped Sr 2 Fe 1.5 Mo 0.5 O 6-δ (SFZxM) perovskites are firstly evaluated as SOEC cathode. • SFZxM materials greatly enhance the chemisorption of CO 2 by increasing the oxygen vacancies concentration. • The introduction of Zr4+ can improve the oxygen ion basicity of SFZxM cathodes. • The improved electrochemical performance is facilitated by the double regulation of oxygen ion basicity and oxygen vacancies. [ABSTRACT FROM AUTHOR]

Herein, we report a facile and effective adsorption strategy to improve the performance of Lithium-Sulfur (Li-S) batteries. MnO 2 nanosheets grown on the surface of highly conductive graphene resulted in a coupled composite bilayer electrode when coated onto a sulfur cathode. In this way, a high initial specific capacity of 1395 mA h g −1 at a rate of 0.5C, a coulombic efficiency approaching 100% and steady cyclic efficiency with a fade rate of 0.3% per cycle from 10 to 100 cycles has been achieved. This hybrid electrode not only shows enhanced electrochemical performance but can also be easily controlled and scaled thereby aiding future commercialization of high-performance Li-S batteries. [ABSTRACT FROM AUTHOR]

• Cu-doped (La 0.2 Sr 0.8) 0.95 Ti 0.65- x Mn 0.35 Cu x O 3- δ(LSTMC)are firstly evaluated as SOEC cathode. • LSTMC greatly enhances the catalytic activity by enhancing the chemisorption of CO 2. • The catalytic reaction mechanisms of LSTMC are discussed. • A max electrolytic current density of 2.33 A cm−2 is obtained under 1.8 V at 800 °C. Solid oxide electrolysis cell (SOEC) is a promising technology to efficiently convert carbon dioxide. However, the lack of suitable cathode, with desirable catalytic activity, limits the advancement of SOEC. Herein, we report a novel (La 0.2 Sr 0.8) 0.95 Ti 0.65- x Mn 0.35 Cu x O 3-δ (LSTMC x , x = 0, 0.05, 0.1 and 0.15) as a high-performance cathode, co-doped with hetero-valent Cu and Mn ions at B-site synergistically regulates the surface environment of LST. Cu doping significantly improved the catalytic activity by enhancing the chemisorption of CO 2 , and Mn doping increased the concentration of oxygen vacancies, resulting in abundant electrochemically active sites. Moreover, the as-prepared LSTMC render a higher electrocatalysis performance (2.33 A cm−2 at 1.8 V and 800 °C) than the previously reported perovskite-based cathodes. In addition, the LSTMC-based single cell did not exhibit any significant performance degradation after long-term stability test (100 h) under pure CO 2. Therefore, this newly developed perovskite is considered as a promising cathode for SOEC. [ABSTRACT FROM AUTHOR]