A new halospinel superionic conductor for high-voltage all solid state lithium batteries

We report a new Li-superionic chloride, Li2Sc2/3Cl4, that crystallizes in a disordered spinel structure, and exhibits an ionic conductivity of 1.5 mS cm(-1)with a low activation energy barrier for Li(+)ion diffusion of 0.34 eV. This material is the first spinel-type superionic halide. Structural elucidationviapowder neutron diffraction reveals a significantly disordered Li+-ion distribution over available tetrahedral and octahedral sites within the lattice, forming an infinitely 3D connected Li(+)ion diffusion pathway comprised of face-sharing octahedra and tetrahedra. Due to the high oxidative stability of Li2Sc2/3Cl4, all solid state lithium batteries employing Li(2)Sc(2/3)Cl(4)and high voltage cathodes (LiCoO2, LiNi(0.6)Mn(0.2)Co(0.2)O(2)or high-Ni LiNi0.85Mn0.1Co0.05O2) - without any coating - exhibit excellent electrochemical performance up to 4.6 V in terms of capacity retention and cycle life.