Enhanced Electrical Conductivities of Complex Hydrides Li<SUB>2</SUB>(BH<SUB>4</SUB>)(NH<SUB>2</SUB>) and Li<SUB>4</SUB>(BH<SUB>4</SUB>)(NH<SUB>2</SUB>)<SUB>3</SUB> by Melting

Abstract

The electrical conductivities of complex hydrides Li2(BH4)(NH2) and Li4(BH4)(NH2)3 consisting of (BH4)− and (NH2)− anions are investigated focusing on their low melting temperatures (365 K for Li2(BH4)(NH2) and 490 K for Li4(BH4)(NH2)3). The two hydrides show lithium fast-ion conductivities of about 1×10−4 S·cm−1 at room temperature. After melting, the total ion conductivities of Li2(BH4)(NH2) and Li4(BH4)(NH2)3 reach 6×10−2 S·cm−1 (378 K) and 2×10−1 S·cm−1 (513 K), respectively. The crystal structure and local atomistic structures closely correlated with the lithium ion conduction before and after melting are also discussed.