Ionic conductivity > 1 mS cm−1 at 25 °C, compressibility enabling > 90% density at 250 − 350 MPa, and cost < $50/kg are desirable for inorganic solid-state electrolytes. Here, the authors report Li1.75ZrCl4.75O0.5 as a solid-state electrolyte capable of satisfying these requirements simultaneously.