Synthesis of closo-CB₁₁H₁₂^– Salts Using Common Laboratory Reagents

Abstract

Lithium and sodium salts of the closo-carbadodecaborate anion [CB 11 H 12 ] − have been shown to form stable solidstate electrolytes with excellent ionic conductivity for all-solid-state batteries (ASSB). However, potential commercial application is currently hindered by the difficult, low-yielding, and expensive synthetic pathways. We report a novel and cost-effective method to synthesize the [CB 11 H 12 ] − anion in a 40% yield from [B 11 H 14 ] − , which can be synthesized using common laboratory reagents. The method avoids the use of expensive and dangerous reagents such as NaH, decaborane, and CF 3 SiMe 3 and shows excellent reproducibility in product yield and purity.

Enhanced Room-Temperature Ionic Conductivity of NaCB11H12 via High-Energy Mechanical Milling

“…Finally, it has been shown that, even though in a nonoptimized system, MM-NCB allows sodium to be reversibly plated/stripped at rt, withstanding decent current densities in comparison with the specific capacities of commonly employed Na-positive electrodes. Such findings prove that the destabilization driving fast ion motion in large-cage hydroborates is not necessarily achieved by further anion mixing, but can be achieved even starting from a unique and cheap precursor, by tuning the stabilization of nonequilibrium disordered phases.…”

Na2B11H13 and Na11(B11H14)3(B11H13)4 as potential solid-state electrolytes for Na-ion batteries

“…However, the synthesis of Na 11 (B 11 H 14 ) 3 (B 11 H 13 ) 4 reported here requires only the use of wet chemistry approaches and common laboratory consumables, which may be more cost-effective than when compared to the majority of the syntheses reported for carboranes. 67…”

“…reported here requires only the use of wet chemistry approaches and common laboratory consumables, which may be more cost-effective than when compared to the majority of the syntheses reported for carboranes. 67 The oxidative stability limit of Na 2 B 11 H 13 was determined to be 2.1 V against Na metal based on the anodic peak observed in its linear sweep voltammogram at 30 °C (Fig. S13 †).…”

Hydrated lithiumnido-boranes for solid–liquid hybrid batteries

“…These superionic results observed for a-LiB 11 -H 14 $(H 2 O) n between 60 and 90 C also correlate to the results observed for the 0.7Li(CB 9 H 10 )-0.3Li(CB 11 H 12 ) mixture, 35 of which, to date, is the lithium boron-hydrogen sample with the highest ionic conductivity at room temperature (6.7 Â 10 À3 S cm À1 ). It is important to highlight that carboranes are more expensive and more difficult to synthesise than carbon free boron-hydrogen salts, 44 such as a-LiB 11 H 14 $(H 2 O) n reported here.…”

“…32 Some of the most promising lithium-boranes as solid-state electrolytes have carboranes in their structure, such as 0.7Li(CB 9 H 10 )-0.3Li(CB 11 H 12 ) and Li 3 (B 11 H 14 )(CB 9 H 10 ) 2 , which present ionic conductivities higher than 1 Â 10 À3 S cm À1 at 25 C. 32,35 However, carboranes usually present high-costs due to the need for expensive and dangerous reagents, as well as, long synthetic processes. 44,45 The optimisation of synthetic processes of metal-boranes with reduced costs is important for further research and application as solid-state electrolyte.…”