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 closotype 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 [B11 H11]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.