Li–Na ternary amidoborane for hydrogen storage: experimental and first-principles study

Abstract

Li–Na ternary amidoborane, Na[Li(NH₂BH₃)₂], was recently synthesized by reacting LiH and NaH with NH₃BH₃. This mixed-cation amidoborane shows improved dehydrogenation performance compared to that of single-cation amidoboranes, i.e., LiNH₂BH₃ and NaNH₂BH₃. In this paper, we synthesized the Li–Na ternary amidoborane by blending and re-crystallizing equivalent LiNH₂BH₃ and NaNH₂BH₃ in tetrahydrofuran (THF), and employed first-principles calculations and the special quasirandom structure (SQS) method to theoretically explore the likelihood for the existence of Li_1−xNa_x(NH₂BH₃) for various Li/Na ratios. The thermodynamic, electronic and phononic properties were investigated to understand the possible dehydrogenation mechanisms of Na[Li(NH₂BH₃)₂].