Lithium ion conductivity of complex hydrides incorporating multiple closo‑type complex anions

We report the lithium ionic conductivities of closo‑type complex hydrides synthesized from various molar ratios of lithium borohydride (LiBH₄) and decaborane (B₁₀H₁₄) as starting materials. The prepared closo‑type complex hydrides comprised [B₁₂H₁₂]²⁻, [B₁₁H₁₁]²⁻, and [B₁₀H₁₀]²⁻ complex anions. In addition, increasing the LiBH₄ content in the starting materials increased the amounts of [B₁₁H₁₁]²⁻ and [B₁₀H₁₀]²⁻, leading to an improved ion conductivity of the prepared sample. The present study offers useful insights into strategies for controlling the complex anion composition in emerging solid electrolytes of closo-type complex hydrides at the molecular level, and improving their ionic conductivities.