Ternary LiBH₄-NaBH₄-MgH₂ composite as fast ionic conductor

In the present paper, ball milled LiBH₄-NaBH₄-MgH₂ ternary-phase composite achieves nearly 100 times as much as the lithium ionic conductivity of the pristine LiBH₄ at a temperature below 373 K. 4LiBH₄-NaBH₄-30%MgH₂ possesses ionic conductivity of 11.2 ms cm⁻¹ at a temperature of 383 K, which is almost 100 times higher than that of pristine LiBH₄. Furthermore, cyclic voltammetry (CV) measurements on these composite samples identified a wide potential window ranging from −1 V to 4 V, demonstrating the electrochemical stability of these samples when Li⁺ ions has been transported. Both X-ray diffraction (XRD) and Fourier Transform infrared spectroscopy (FTIR) results verified the structural stability of LiBH₄-NaBH₄-MgH₂ composites during the temperature ramping process. Both phase transformation enthalpies and temperatures for LiBH₄ were all reduced according to differential scanning calorimetry (DSC) measurements, implying that the high temperature phase of LiBH₄ could be effectively stabilized by co-additives of NaBH₄-MgH₂.