Improved and Scalable Synthesis of [Et4N][closo-1-CHB9H9]

Solubility of metal-boron-hydrogen compounds

Boron-hydrogen compounds are of increasing importance as electrolytes in solid state batteries, for hydrogen storage and possibly as high temperature super conductors. Solvent based methods are of increasing importance to obtain pure products, for purification of materials and also for the synthesis of novel compounds. In this context, the solubility information of several classes of metal-boron-hydrogen compounds such as borohydrides, closo-decahydridodecaborates, closo-dodecahydridododecaborates, arachno- and nido-hydridoborates in typical solvents is vital. This information is currently dispersed in the literature, hence the need to present a cohesive summary and comparison of these properties. This review collects, analyses and discusses the available data to provide inspiration for the future design of new synthesis routes and the discovery of novel materials.

Facile Synthesis of Potassium Decahydrido-Monocarba-closo-Decaborate Imidazole Complex Electrolyte for All-Solid-State Potassium Metal Batteries

All-solid-state potassium metal batteries have caught increasing interest owing to their abundance, cost-effectiveness, and high energy/power density. However, their development is generally constrained by the lack of suitable solid-state electrolytes. Herein, we report a new complex KCB9H10 ⋅ 2C3H4N2, synthesized by grinding and heating the mixture of potassium decahydrido-monocarba-closo-decaborate (KCB9H10) and imidazole (C3H4N2) under mild conditions, to achieve the K-ion superionic solid-state electrolyte. The crystal structure was revealed as an orthorhombic lattice with the space group of Pna21 by FOX software. The diffusion properties for K+ in the crystal structure were calculated using the climbing image nudged elastic band (CI-NEB) method. KCB9H10 ⋅ 2C3H4N2 exhibited a high ionic conductivity of 1.3×10-4 S cm-1 at 30 °C, four orders of magnitude higher than that of KCB9H10. This ionic conductivity is also the highest value of hydridoborate-based K+ conductors reported. Moreover, KCB9H10 ⋅ 2C3H4N2 demonstrated a K+ transference number of 0.96, an electrochemical stability window of 1.2 to 3.2 V vs. K/K+, and good stability against the K metal coated by a layer of potassium imidazolate (KIm). These great performances make KCB9H10 ⋅ 2C3H4N2 a promising K-ion solid-state electrolyte.

New approaches to the functionalization of the 1-carba-closo-decaborate anion

Two new approaches to the functionalization of the 1-carba-closo-decaborate anion [1-CB₉H₁₀]^- at boron atoms via the ring-opening of its 1,4-dioxane derivative with various nucleophiles and Pd-catalysed cross-coupling of its iodo derivative with aromatic amines and heteroaromatics were developed.