Experimental Corroboration of Lithium Orthothioborate Superionic Conductor by Systematic Elemental Manipulation.

The Li superionic conductor LiBS has been theoretically predicted as an ideal solid electrolyte (SE) due to its low Li migration energy barrier and high ionic conductivity. However, the experimentally synthesized LiBS has a 10 times lower ionic conductivity. Herein, we investigate the effect of a series of cation and anion substitutions in LiBS SE on its ionic conductivity, including LiMBS (M = Cu, Zn, Sn, P, W, = 0.05, 0.1, 0.2, 0.25), LiBSX (X = O, Cl, Br, I, = 0.05, 0.1) and LiPBSCl ( = 0.05, 0.1, 0.15, 0.2, 0.4, 0.6). Amorphous ionic conductor LiPBSCl has a high ion conductivity of 0.52 mS cm at room temperature with an activation energy of 0.41 eV. The electrochemical performance of all-solid-state batteries with LiPBSCl SEs show stable cycling with a discharge capacity retention of >97% after 200 cycles at 1 under 55 °C.