Monolithic Flexible Supercapacitors Integrated into Single Sheets of Paper and Membrane via Vapor Printing

Abstract

A novel approach to fabricate supercapacitors (SCs) via vapor printing, specifically oxidative chemical vapor deposition (oCVD), is demonstrated. Compared to stacking multiple layers into a SC, this method enables the monolithic integration of all components into a single-sheet substrate, minimizing the inactive materials and eliminating the possibility of multilayer delamination. Electrodes comprised of pseudocapacitive material, poly(3,4-ethylenedioxythiophene) (PEDOT), are deposited into both sides of a sheet of flexible porous substrate. The film deposition and patterning are achieved in a single step. The oCVD PEDOT penetrates partially into the porous substrate from both surfaces, while leaving the interior of the substrate serving as a separator. Near the surface, the PEDOT coating conforms to the substrate's structure without blocking the pores, resembling the substrate's intrinsic morphology with high surface area. The porously structured PEDOT coating, paired with in situ ion gel electrolyte synthesis, gives enhanced electrode-electrolyte interfaces. The monolithic device demonstrates high volumetric capacitance (11.3 F cm ), energy density (2.98 mWh cm ), and power density (0.42 W cm ). These outstanding performance metrics are attributed to the large loading of active materials, minimization of inactive materials, and good electrode-electrolyte interfaces. SC arrays can be printed on a single substrate without the use of wire interconnects.

Monolithic Integration of All‐in‐One Supercapacitor for 3D Electronics

“…[1][2][3][4][5] As an energy storage device and circuit element, supercapacitor has been widely investigated in the last two decades as a discrete component. [13,14] All-in-one supercapacitors enable monolithic integration of all of the components into one substrate, which can drastically minimize the proportion of inactive material and avoid the possibility of multilayer delamination. [6,7,11,12] This discrete stacking approach increases weight and volume, and decreases mechanical integrity, leading to a low gravimetric or volumetric capacity.…”

“…[6][7][8][9][10] State-of-the-art supercapacitors predominantly present sandwiched architecture, where current collector, cathode, separator, and anode are separately prepared and then assembled by stacking. [13][14][15] The substrates for the all-in-one supercapacitor can act as the separators simultaneously, where two sides of the substrate are metallized to form a conductive/nonconductive/conductive sandwiched structure. [13,14] All-in-one supercapacitors enable monolithic integration of all of the components into one substrate, which can drastically minimize the proportion of inactive material and avoid the possibility of multilayer delamination.…”

“…[6,7,11,12] This discrete stacking approach increases weight and volume, and decreases mechanical integrity, leading to a low gravimetric or volumetric capacity. [14,16,17] The conductive layer displays a 3D framework structure, which can facilitate efficient ion/electron transportation. [13][14][15] The substrates for the all-in-one supercapacitor can act as the separators simultaneously, where two sides of the substrate are metallized to form a conductive/nonconductive/conductive sandwiched structure.…”

“…[13,14] All-in-one supercapacitors enable monolithic integration of all of the components into one substrate, which can drastically minimize the proportion of inactive material and avoid the possibility of multilayer delamination. In the previous works, different 3D porous sheets, such as paper, [14] nylon membrane, [14] hydrogel, [17] and polypropylene [16] films, have been utilized as the substrates. [14,16,17] The conductive layer displays a 3D framework structure, which can facilitate efficient ion/electron transportation.…”

“…These prototypes demonstrate a conceptual all-in-one architecture and show superior electrochemical performance. [14] 2. [18,19] Among the electrode materials, 2D materials were intensively studied for their high theoretical capacitance due to their large specific surface area (SSA) and abundant electrochemical active sites.…”