High interfacial capacitance in LATP/LSCO/LATP ceramics prepared by film rolling

The growing demand for advanced electronics requires high-performance capacitors featuring large capacitance, low leakage, excellent stability, and enhanced safety. Normally, the high capacitance in liquid based supercapacitor and/or electrolyte capacitor cannot be used in integrated electronics, while the co-fired multilayer ceramic capacitor has inferior specific capacity. As a combination of the above device structures, a stack of highly conductive ceramics (ionic or electronic) with a highly resistive interfacial layer formed in between, was demonstrated to realize ceramic-based supercapacitor. This study investigates a ceramic-based interfacial capacitor using Li_1.3Al_0.3Ti_1.7(PO₄)₃ (LATP) as an ionic conductor (optimal ionic conductivity: 4.18 × 10−4 S/cm) and La_0.9Sr_0.1CoO₃ (LSCO0.1) as an electronic conductor (conductivity: ∼10−1 to 101 S/cm). Utilizing compatible sintering temperatures, LATP/LSCO/LATP sandwich structures were fabricated via film rolling and consequent stacking, followed by co-firing. Interfacial reactions during firing form high-resistance interface layers that prevent the long-range migration of carriers. Consequently, LATP/LSCO/LATP sandwich structures exhibited a specific capacitance exceeding 0.1 μF/cm2 (<100 Hz) at room temperature. Compared to unitary LSCO, the total electronic conductivity of LATP/LSCO/LATP decreased by several orders of magnitude, confirming that the high specific capacitance primarily originates from the generated LATP/LSCO interfaces. This work presents a new strategy for developing interfacial ceramic capacitors and offers significant potential for fabricating advanced all-solid-state capacitive devices.