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

Abstract

Solid-state sodium batteries have attracted great attention owing to their improved safety, high energy density, large abundance and low cost of sodium compared to current Li-ion batteries. Sodium-boranes have been...

A High‐Rate and Long‐Life Sodium Metal Battery Based on a NaB3H8 ⋅ xNH3@NaB3H8 Composite Solid‐State Electrolyte

“…During the heating stage of the first cycle, NaB 3 H 8 • xNH 3 @NaB 3 H 8 presented an ionic conductivity of 8.4×10 À 4 S cm À 1 at 25 °C and reaching 2.1×10 À 2 S cm À 1 at 45 °C after the order-disorder phase transformation. The RT Na + conductivity of NaB 3 H 8 • xNH 3 @NaB 3 H 8 is higher than those of most hydridoborates previously reported and only [5c,f,h,7,8,9b,10a, 16,26] Angewandte Chemie Forschungsartikel lower when compared to closo-carbaborates, such as ballmilled NaCB 11 H 12 , [5h] Na 4 (CB 11 H 12 ) 2 (B 12 H 12 ), [26c] and Na 2 -(CB 9 H 10 )(CB 11 H 12 ) [8b] (Figure 4b). Above 45 °C, after phase transition, the Na + conductivity becomes comparable to that observed for NaCB 9 H 10 or the ball-milled NaCB 11 H 12 (Figure 4b).…”

“…The electronic conductivity of NaB 3 H 8 • xNH 3 @NaB 3 H 8 was also measured and calculated to be 3.7×10 À 8 S cm À 1 at 30 °C (Figure 5a), suggesting negligible electron conduction. Moreover, by using the linear sweep voltammetry (LSV) measurements (Figure 5b), the oxidative stability limit of NaB 3 H 8 • xNH 3 @NaB 3 H 8 was determined to be 3.85 V (vs. Na + /Na) at 30 °C, higher than those of NaB 11 H 14 (2.6 V), [15a] Na 11 (B 11 H 14 ) 3 (B 11 H 13 ) 4 (2.1 V), [16] and Na 2 B 12 H 12 (3.45 V), [10d] but lower than those of NaCB 11 H 12 (4.1 V) [5h] and conjuncto-Na 3 B 24 H 23 (6.7 V). [15c] The reduction reaction in the anodic scan occurs at about 1.34 V. These indicate a stable potential window of 1.34-3.85 V for NaB 3 H 8 • xNH 3 @NaB 3 H 8 .…”

“…Even after forming the mixed‐anion solid solutions, the optimized Na 2 (BH 4 )(NH 2 ) and Na 11 (B 11 H 14 ) 3 (B 11 H 13 ) 4 still presented a RT Na + conductivity of less than 10 −4 S cm −1 [15b,16] . Besides, the reported nido ‐borate‐based SEs have narrow electrochemical stability windows [15a,16] . These disadvantages restrict the development of high‐performance hydridoborate‐based AS 3 MBs.…”

A High‐Rate and Long‐Life Sodium Metal Battery Based on a NaB3H8 ⋅ xNH3@NaB3H8 Composite Solid‐State Electrolyte

“…During the heating stage of the first cycle, NaB 3 H 8 • xNH 3 @NaB 3 H 8 presented an ionic conductivity of 8.4×10 À 4 S cm À 1 at 25 °C and reaching 2.1×10 À 2 S cm À 1 at 45 °C after the order-disorder phase transformation. The RT Na + conductivity of NaB 3 H 8 • xNH 3 @NaB 3 H 8 is higher than those of most hydridoborates previously reported and only [5c,f,h,7,8,9b,10a, 16,26] Angewandte Chemie lower when compared to closo-carbaborates, such as ballmilled NaCB 11 H 12 , [5h] Na 4 (CB 11 H 12 ) 2 (B 12 H 12 ), [26c] and Na 2 -(CB 9 H 10 )(CB 11 H 12 ) [8b] (Figure 4b). Above 45 °C, after phase transition, the Na + conductivity becomes comparable to that observed for NaCB 9 H 10 or the ball-milled NaCB 11 H 12 (Figure 4b).…”

Stannaborates: tuning the ion conductivity of dodecaborate salts with tin substitution

“…These anions have been paired with different alkali metal cations such as lithium, sodium, and potassium and show excellent ionic conductivity performance at elevated temperatures, for example, Li 2 B 12 H 12 (8 × 10 −2 S cm −1 at 280 °C), Na 2 B 10 H 10 (2 × 10 −2 S cm −1 at 150 °C), and KB 11 H 14 (1 × 10 −4 S cm −1 at 150 °C). 11–14…”