Abstract New Li-ion conductors with several different structure types are reported. Li 4B 7O 12(Cl,Br) and LiM 2P 3O 12 (MZr, Hf) have framework structures. The others are based on structures with isolated polyhedra in a network of edge-linked Li polyhedra and include Li 2+xC 1−xB xO 3, Li 3−x B 1−xC xO 3, Li 4+xSi 1−xSi 1−xAl xO 4, Li 4−xSi 1−xP xO 4, Li 4−2xSi 1−xS xO 4 and Li 5−xAl 1−xSi xO 4. Li 0.8Zr 1.8 Ta 0.2P 3O 12 has the best room temperature conductivity, ∼5 × 10 −6 (Ωcm) −1. At 300°C, the conductivities of Li 3.75Si 0.75P 0.25O 4, Li 3.4Si 0.3O 4 and Li 2.25C 0.75B 0.25O 3 are 1 × 10 −2 (Ωcm) −1. These compositions resist attack by molten li at 200°C and some can be easily prepared as dense ceramics.