Stamping Fabrication of Flexible Planar Micro‐Supercapacitors Using Porous Graphene Inks

Abstract

High performance, flexibility, safety, and robust integration for micro-supercapacitors (MSCs) are of immense interest for the urgent demand for miniaturized, smart energy-storage devices. However, repetitive photolithography processes in the fabrication of on-chip electronic components including various photoresists, masks, and toxic etchants are often not well-suited for industrial production. Here, a cost-effective stamping strategy is developed for scalable and rapid preparation of graphene-based planar MSCs. Combining stamps with desired shapes and highly conductive graphene inks, flexible MSCs with controlled structures are prepared on arbitrary substrates without any metal current collectors, additives, and polymer binders. The interdigitated MSC exhibits high areal capacitance up to 21.7 mF cm −2 at a current of 0.5 mA and a high power density of 6 mW cm −2 at an energy density of 5 µWh cm −2. Moreover, the MSCs show outstanding cycling performance and remarkable flexibility over 10 000 charge-discharge cycles and 300 bending cycles. In addition, the capacitance and output voltage of the MSCs are easily adjustable through interconnection with well-defined arrangements. The efficient, rapid manufacturing of the graphene-based interdigital MSCs with outstanding flexibility, shape diversity, and high areal capacitance shows great potential in wearable and portable electronics.

Electrochemically Exfoliated Chlorine‐Doped Graphene for Flexible All‐Solid‐State Micro‐Supercapacitors with High Volumetric Energy Density

“…The maximum volumetric energy density of the Cl2-G-MSC is 97.9 mW h cm −3 at the volumetric power density of 3.4 W cm −3 , and the maximum volumetric power density is 38.5 W cm −3 at the volumetric energy density of 8.8 mW h cm −3 . In addition, our microdevice performs favorably, when compared to a number of recently reported G-based MSCs as shown in Figure 6f, such as porous graphene-based MSCs (2.95 mWh cm −3 at 149 mW cm −3 ), [15] N-GQDs//MoS 2 -QDs asymmetric MSCs (0.55 mWh cm −3 at 400 mW cm −3 ), [17] dual-mesoporous PPy/graphene MSC (0.9 mWh cm −3 at 397 mW cm −3 ), [18] anisotropic boron-carbon nanosheets FSC (167.05 mWh cm −3 at 150 W cm −3 ), [25] electrochemically exfoliated O, P-functionalized holey graphene MSCs (4.24 mWh cm −3 at 120 mW cm −3 ), [46] carbon-nanosphereslaser scribed graphene supercapacitors (0.18 mWh cm −3 at 10 mW cm −3 ), [56] YP80/G composite (43 mWh cm −3 at 7.6 W cm −3 ), [57] and especially fluorine-modified graphene MSCs (56 mWh cm −3 at 60 mW cm −3 ). [42] The single flexible Cl2-G-MSC with the high voltage of 3.5 V could easily light up an LED (Figure 6g) with different colors when fully charged, indicating the widespread potential in flexible energy-storage application.…”

“…[13,14] In addition, conventional microdevices with sandwich structures involving conductive metal wire generally suffer from rather limited mechanical flexibility, high cost, and heavy weight. [15,16] By contrast, allsolid-state planar micro-supercapacitors (MSCs) constructed by screen-printing and dry-transferring technology on appropriate substrates exhibit obvious advantages, such as an easy integration, high power density, rapid charge/discharge rates, prolonged cycling stability, and high safety, which have been recognized as among the most promising microdevices in the fields of integrated electronics. [17][18][19][20][21] More recently, considerable efforts have been dedicated to engineering a variety of electrode materials with superior energy-storage capability to make thinner, smaller, and more versatile MSCs.…”

Planar Graphene‐Based Microsupercapacitors

“…The common printing methods include screen printing, [151,152] spray printing, [106,153] and stamping. [154][155][156] Screen printing is a mature and low-cost printing technique, which uses a mesh with designed blocking stencil pattern to apply slurry-like inks on the substrate surface to fabricate MSCs. It is compatible with diverse substrate.…”

Rational Formulation of Graphene Nanocomposite Ink for 2D Mutually Embedded Structure Interdigital Microsupercapacitors

“…Especially, we note that most reported printable inks contain high boiling or noxious solvents with the purpose of either improving the dispersibility of the active materials or adjusting the rheological properties. 35,36 Most importantly, the π−π stacking and hydrophobicity of graphene, the inefficient nanomaterial utilization, and sophisticated preparation processing of the electrode material reduce the energetic performance of printed flexible MSCs. 4,37 In this regard, the component engineering strategies of graphene-based inks, such as interlayer intercalation, material hybridization, and synergistic effect, are of vital importance to maximize the energy storage performance of MSCs but are still at the nascent stage.…”

“…Albeit this significant progress, quite limited success has been achieved on graphene-based devices with a high-energy-harvesting property and amenable to large-scale production with high reproducibility. Especially, we note that most reported printable inks contain high boiling or noxious solvents with the purpose of either improving the dispersibility of the active materials or adjusting the rheological properties. , Most importantly, the π–π stacking and hydrophobicity of graphene, the inefficient nanomaterial utilization, and sophisticated preparation processing of the electrode material reduce the energetic performance of printed flexible MSCs. , In this regard, the component engineering strategies of graphene-based inks, such as interlayer intercalation, material hybridization, and synergistic effect, are of vital importance to maximize the energy storage performance of MSCs but are still at the nascent stage. ,, Consequently, questing functional viscous aqueous inks with appropriate printability and uninvolved increase in the source of significant cost is of paramount importance for the scalable production of high-performance MSCs.…”