Enhanced Electrical Conductivities of Complex Hydrides Li₂(BH₄)(NH₂) and Li₄(BH₄)(NH₂)₃ 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.