Braga M Helena, Oliveira Joana E, Kai Tianhan, Murchison Andrew J, Bard Allen J, Goodenough John B
The Materials Institute, Department of Mechanical Engineering , The University of Texas at Austin , Austin , Texas 78712 , United States.
LAETA, Department of Engineering Physics, FEUP , University of Porto , 4200-465 Porto , Portugal.
J Am Chem Soc. 2018 Dec 26;140(51):17968-17976. doi: 10.1021/jacs.8b09603. Epub 2018 Dec 14.
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 ABaClO (A = Li, Na) are shown by two different types of measurement and different consistent analyses to have extraordinarily high dielectric constants, varying from 10 at 25 °C to 10 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 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.
从晶体管到电容器等各种电气应用都需要具有高介电常数的材料。通过两种不同类型的测量和不同的一致性分析表明，成分ABaClO（A = Li，Na）的铁电非晶氧化物（玻璃）碱离子电解质具有极高的介电常数，如果玻璃经过适当处理，介电常数在25°C时为10，在220°C时为10 。这些异常高的介电性能与25°C时的碱离子电导率共存，该电导率与锂离子电池中最好的有机液体电解质相当，并且在Au/玻璃电解质/Au电池中的循环伏安法（CV）在-10至+10 V范围内是稳定的。一个从微观上解释CV曲线所有关键特征的模型表明，在Au/玻璃电解质/Au异质结中，在金/电解质界面形成的双电层电容器在施加电压V = ±2.1 V时会发生反向极化，导致单个物理电容器在-10至+10 V范围内有三个几乎相等的放电电容。
