Raising the surface treatment temperature, ceramic solid-state electrolyte β′′-Al2O3 decorated with now highly metallic lead microspheres improves surface wetting of molten sodium and thus the performance of sodium-sulfur batteries.

We present a novel anode interface modification on the β″-alumina solid-state electrolyte that improves the wetting behavior of molten sodium in battery applications. Heat treating a simple slurry, composed only of water, acetone, carbon black, and lead acetate, formed a porous carbon network decorated with PbO x (0 ≤ x ≤ 2) nanoparticles between 10 and 50 nm. Extensive performance analysis, through impedance spectroscopy and symmetric cycling, shows a stable, low-resistance interface for close to 6000 cycles. Furthermore, an intermediate temperature Na−S cell with a modified β″-alumina solid-state electrolyte could achieve an average stable cycling capacity as high as 509 mA h/g. This modification drastically decreases the amount of Pb content to approximately 3% in the anode interface (6 wt % or 0.4 mol %) and could further eliminate the need for toxic Pb altogether by replacing it with environmentally benign Sn. Overall, in situ reduction of oxide nanoparticles created a high-performance anode interface, further enabling large-scale applications of liquid metal anodes with solid-state electrolytes.

Coordination polymers (CPs) supporting tunable through-framework conduction and responsive properties are of significant interest for enabling a new generation of active devices. However, such architectures are rare. We report a redox-active CP composed of two-dimensional (2D) lattices of coordinatively bonded Mo(INA) clusters (INA = isonicotinate). The 2D lattices are commensurately stacked and their ordering topology can be synthetically tuned. The material has a hierarchical pore structure (pore sizes distributed between 7 and 33 Å) and exhibits unique CO adsorption (nominally Type VI) for an isotherm collected at 195 K. Furthermore, cyclic voltammetry and electrokinetic analyses identify a quasi-reversible feature at E = -1.275 V versus ferrocene/ferrocenium that can be ascribed to the [Mo(INA)] redox couple, with an associated standard heterogeneous electron transfer rate constant k = 1.49 s. The tunable structure, porosity, and redox activity of our material may render it a promising platform for CPs with responsive properties.