Wafer-Scale Fabrication and Encapsulation of Micro Supercapacitor

Micro supercapacitors (MSCs) with ultrahigh capacitance density and thin-film fabrication capability are promising energy storage and power-filtering devices for integrated systems. However, the wafer-scale fabrication and encapsulation of MSCs are challenging, mainly resulting from incompatibility between chemically active electrolytes and standard microfabrication techniques. Here, we report a complete wafer-scale preparation of well-encapsulated MSCs based on newly developed electrolyte deposition and device package methods. The proposed encapsulation process only compromises spin-coating and photolithography processes; hence, it is cost-effective, gives high throughput, and is intrinsically scalable. The experimental results demonstrate that the encapsulation approach promises a longer device lifetime and minor impacts on capacitive performances. The prototype MSC has a capacitance density exceeding 2 mF/cm
²
at a high scan rate of 10 V/s and a time constant of ~8 ms, meeting the AC-line-filtering requirements. Moreover, the process uniformity, operation leakage current, and temperature endurance range are also investigated and discussed. This work will significantly promote the practical application of MSCs.