All-printed supercapacitor array with vertical stacking

Additive manufacturing technologies offer synergistic benefits in supercapacitor manufacturing through sequential layer-by-layer processes, high resource efficiency, sustainable operation and amenability for flexible devices. While cell-level fabrication of a printed supercapacitor has been established, an efficient expansion strategy for developing an array-level supercapacitor system is still required. An all-printed supercapacitor array, composed of multiple supercapacitors with internal interconnections in series and parallel, is introduced in this work. The process is based on sequential layer-by-layer printing using customized inks with interconnections between cells done automatically by extended current collector lines, which eliminate additional interconnection steps. The effect of series and parallel connections on array performance is evaluated through experimental and theoretical analysis of array configuration dependence, and an array design guideline is suggested based on the results. The entire process is compatible with flexible substrates, allowing vertical stacking through a controlled cut-and-fold process. Vertical stacking increases the areal efficiency significantly with only negligible loss of performance. The measured performance factors of the arrays are in good agreement with theoretical expectations, yielding an areal capacitance of 0.101 F/cm2, areal energy density of 0.081 mWh/cm2 and areal power density of 1.21 mW/cm2 for a 3 × 3 array. The expected performance factors for various array configurations are also provided based on simulation results.