Investigation of the wetting behavior of Na and Na alloys on uncoated and coated Na-β”-alumina at temperatures below 150 °C

Bismuth Islands for Low-Temperature Sodium-Beta Alumina Batteries

“…(iii) As a result, NBBs fabricated using our methods can be operated at much lower temperatures than typical NBBs and without the need for conditioning cycles. Importantly, we found that it was isolated bismuth islands, as opposed to a continuous bismuth film, that significantly improve cell performance, retaining 94% charge after the initial cycle. This methodology represents a major advance toward Na wetting engineering, as it provides a protocol to effectively enhance wettability and ultimately leads to improved battery performance.…”

“…It is well-known that poor Na wetting is related to the formation of surface oxidation of liquid Na when β″-Al 2 O 3 is exposed to moisture-rich conditions (Figure S1), , necessitating conditioning cycles to reach full cell capacity . To address this wetting problem, additional metal coatings (e.g., Sn, Bi, and In) or porous nanostructures (e.g., Ni nanowires, Pt mesh, and Pb particles) were applied to the surface of β″-Al 2 O 3 to increase the adhesive energy between metal (Na)–metal coating contacts and to prevent moisture from being absorbed onto β″-Al 2 O 3 . ,− In addition, the application of various Na alloys with Cs, Sn, and Bi, which have a high work of adhesion ( W adh ) with β″-Al 2 O 3 , has been reported to show improvements in the wetting behavior. , Taking advantage of this metal passivation effect, this approach, where metal ions are considered potential impurities, causes a problem with Na + ion transport and limits full utilization of the contact area because of the presence of impurity metals on the surface of β″-Al 2 O 3 . ,, Therefore, metallic elements that can be alloyed with Na in small amounts must be identified such that Na + ion transport is unimpeded while effectively protecting the surface of β″-Al 2 O 3 and as a result, removing the need for conditioning cycles.…”

“…10,18−21 In addition, the application of various Na alloys with Cs, Sn, and Bi, which have a high work of adhesion (W adh ) with β″-Al 2 O 3 , has been reported to show improvements in the wetting behavior. 20,22 Taking advantage of this metal passivation effect, this approach, where metal ions are considered potential impurities, causes a problem with Na + ion transport and limits full utilization of the contact area because of the presence of impurity metals on the surface of β″-Al 2 O 3 . 18,19,23 Therefore, metallic elements that can be alloyed with Na in small amounts must be identified such that Na + ion transport is unimpeded while effectively protecting the surface of β″-Al 2 O 3 and as a result, removing the need for conditioning cycles.…”

A β”‐Alumina/Inorganic Ionic Liquid Dual Electrolyte for Intermediate‐Temperature Sodium–Sulfur Batteries

“…[25][26][27][28][29][30] The BASE is known to manifest a high ionic conductivity at IT (50 mS cm −1 at 150 °C), making them uniquely applicable for Na-S batteries for their ability to prohibit polysulfides migration. [29,31,32] The liquid electrolyte, which is introduced in the positive electrode compartment, enhances the reactivity of polysulfide electrode materials, thus improving their utilization. Although research on IT Na-S batteries is still in its incipient stages, the availability of a wider variety of materials, such as some polymers suitable as IT cell components, makes them more promising than their HT counterparts.…”

Sparked Reduced Graphene Oxide for Low-Temperature Sodium-Beta Alumina Batteries

“…This metal coating approach can be explained according to the thermodynamic work of adhesion w adh , which is correlated with the surface energy of liquid Na γ l,v , the surface energy of the solid surface γ s,v , and the interfacial energy γ l,s , as described by the Young–Dupre equation w adh /γ l,v = 1 + cos θ, where θ represents the contact angle and γ l,v is replaced by (γ s,v – γ l,s )/cos θ from Young’s equation . With a given γ liquid Na,v of 192.41 mJ/m 2 at 450 K, for example, an appropriate metal coating on the β″-Al 2 O 3 surface, such as Ni, Sn, Bi, or Pb, can increase w adh with liquid Na and then reduce θ, consequently improving the wetting. − In such cases, enhanced liquid Na–metal wetting originates from the increased w adh . Given that γ is a function of T , P , and the crystal plane and is an intrinsic property of the material, the choice of metals inevitably determines the liquid Na wettability; therefore, there is little room to improve the Na + transport.…”