(Graph Presented) Some of the authors have reported that a complex hydride, Li(BH4), with the (BH4)- anion exhibits lithium fast-ion conduction (more than 1 ± 10-3 S/cm) accompanied by the structural transition at ∼390 K for the first time in 30 years since the conduction in Li2(NH) was reported in 1979. Here we report another conceptual study and remarkable results of Li2(BH 4)(NH2) and Li4(BH4)(NH 2)3 combined with the (BH4)- and (NH2)- anions showing ion conductivities 4 orders of magnitude higher than that for Li(BH4) at RT, due to being provided with new occupation sites for Li+ ions. Both Li2(BH 4)(NH2) and Li4(BH4)(NH 2)3 exhibit a lithium fast-ion conductivity of 2 × 10-4 S/cm at RT, and the activation energy for conduction in Li 4(BH4)(NH2)3 is evaluated to be 0.26 ev, less than half those in Li2(BH4)(NH2) and Li(BH4). 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.
ASJC Scopus subject areas
- Colloid and Surface Chemistry