Institute for Materials Research, Tohoku University, Katahira 2-1-1, Sendai, 980-8577, Japan.
J Am Chem Soc. 2009 Nov 18;131(45):16389-91. doi: 10.1021/ja907249p.
Some of the authors have reported that a complex hydride, Li(BH(4)), with the (BH(4))(-) anion exhibits lithium fast-ion conduction (more than 1 x 10(-3) S/cm) accompanied by the structural transition at approximately 390 K for the first time in 30 years since the conduction in Li(2)(NH) was reported in 1979. Here we report another conceptual study and remarkable results of Li(2)(BH(4))(NH(2)) and Li(4)(BH(4))(NH(2))(3) combined with the (BH(4))(-) and (NH(2))(-) anions showing ion conductivities 4 orders of magnitude higher than that for Li(BH(4)) at RT, due to being provided with new occupation sites for Li(+) ions. Both Li(2)(BH(4))(NH(2)) and Li(4)(BH(4))(NH(2))(3) exhibit a lithium fast-ion conductivity of 2 x 10(-4) S/cm at RT, and the activation energy for conduction in Li(4)(BH(4))(NH(2))(3) is evaluated to be 0.26 eV, less than half those in Li(2)(BH(4))(NH(2)) and Li(BH(4)). This study not only demonstrates an important direction in which to search for higher ion conductivity in complex hydrides but also greatly increases the material variations of solid electrolytes.
一些作者首次报道了一种复杂的氢化物 Li(BH4)，其中（BH4）-阴离子具有锂离子快速传导（超过 1 x 10-3 S/cm），并伴有大约 390 K 的结构转变，这是自 1979 年报道 Li(2)(NH)的传导以来 30 年来的首次。在这里，我们报告了另一个概念性研究和显著结果，即 Li(2)(BH4)(NH2)和 Li(4)(BH4)(NH2)3 与（BH4）-和（NH2）-阴离子结合，显示出离子电导率比 RT 时的 Li(BH4)高 4 个数量级，这是由于提供了新的 Li+离子占据位点。Li(2)(BH4)(NH2)和 Li(4)(BH4)(NH2)3 在 RT 时均表现出 2 x 10-4 S/cm 的锂离子快速离子电导率，并且 Li(4)(BH4)(NH2)3 中传导的活化能评估为 0.26 eV，不到 Li(2)(BH4)(NH2)和 Li(BH4)的一半。这项研究不仅展示了在复杂氢化物中寻找更高离子电导率的重要方向，而且大大增加了固体电解质的材料变化。
