摘要： Materials having a high dielectric constant are needed for a variety of electrical applications from transistors to capacitors. Ferroelectric amorphous-oxide (glass) alkali-ion electrolytes of composition A2.99Ba0.005ClO (A = Li, Na) are shown by two different types of measurement and different consistent analysis to have extraordinarily high dielectric constants varying from 109 at 25°C to 1010 at 220°C if the glass is properly conditioned. These anomalously high dielectric properties coexist with alkali-ion conductivities at 25°C that are equivalent to those of the best organic-liquid electrolytes of a Li-ion cell, and cyclic voltammetry (CV) in a Au/glass electrolyte/Au cell is stable from ?10 to +10 V. A model to interpret microscopically all the key features of the CV curves shows that the electric-double-layer capacitors (EDLCs) that form at the gold/electrolyte interfaces in the Au/glass electrolyte/Au heterojunction reverse polarization at an applied voltage V = ± 2.1 V resulting in three almost equivalent discharging capacitances for a single physical capacitor from -10 to +10 V.