An official website of the United States government
Supercapacitors and batteries are essential for sustainable energy development. However, the bottleneck is the associated high cost, which limits bulk use of batteries and supercapacitors. In this context, realizing that the cost of energy‐storage device mainly depends on materials, synthesis processes/procedures, and device fabrication, an effort is made to rationally design and develop novel low‐cost electrode materials with enhanced electrochemical performance in asymmetric supercapacitors. Herein, surface functionalization approach is adopted to design low‐cost 3D mesoporous and nanostructured nickel–nickel oxide electrode materials using facile synthesis for application in supercapacitors. It is demonstrated that the 3D mesoporous Ni provides the high surface area and enhanced ionic conductivity, while germanium functionalization improves the electrical conductivity and reduces the charge‐transfer resistance of NiO. Surface functionalization with Ge demonstrates the significant improvement in specific capacitance of NiO. The asymmetric supercapacitor using these Ge‐functionalized NiO–Ni electrodes provides a specific capacitance of 304 Fg−1(94 mF cm−2), energy density of 23.8 Wh kg−1(7.35 μWh cm−2), and power density of 6.8 kW kg−1(2.1 mW cm−2) with excellent cyclic stability of 92% after 10 000 cycles. To validate their practical applications, powering the digital watch using the asymmetric supercapacitors in laboratory conditions is demonstrated.
more »
« less
This content will become publicly available on August 26, 2026
Rapid 3D Printing of Nanoporous Microsupercapacitor Electrodes Using Projection Two‐Photon Lithography
ABSTRACT Despite their high power density, microsupercapacitors (MSCs) are impractical for many energy storage applications due to their limited energy density. Their energy density can be increased by shaping the electrodes into 3D structures with high specific surface area (SSA). Direct printing of nanoporous 3D electrodes is a promising approach for achieving high SSA. However, conventional nanoscale 3D printing is too slow due to point‐by‐point processing. Here, we have employed the projection two‐photon lithography technique to fabricate nanoporous 3D electrodes via a rapid layer‐by‐layer mechanism. The 3D MSC electrodes are engineered as an array of nanoporous polymeric micropillars that are printed with customizable spacing and count over a 0.25 cm2area. After printing, these micropillars are conformally coated with titanium nitride to form conductive 3D electrodes, which exhibit a specific capacitance of 361 μF/cm2. This is two orders of magnitude higher than the capacitance of the flat surface and exceeds the capacitance of both traditional bare electrodes, such as single‐wall carbon nanotubes (< 100 μF/cm2), and electrodes produced by photo‐polymerization 3D printing (˜200 μF/cm2). As our work demonstrates that high energy density 3D electrodes can be rapidly fabricated, it significantly expands the utility of MSCs as miniaturized energy storage devices.
more »
« less
- Award ID(s):
- 2045147
- PAR ID:
- 10630937
- Publisher / Repository:
- Wiley
- Date Published:
- Journal Name:
- Engineering Reports
- Volume:
- 7
- Issue:
- 8
- ISSN:
- 2577-8196
- Subject(s) / Keyword(s):
- additive manufacturing direct laser writing electrochemical energy storage photopolymerization
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
Abstract Extensive research into green technologies is driven by the worldwide push for eco‐friendly materials and energy solutions. The focus is on synergies that prioritize sustainability and environmental benefits. This study explores the potential of abundant, non‐toxic, and sustainable resources such as paper, lignin‐enriched paper, and cork for producing laser‐induced graphene (LIG) supercapacitor electrodes with improved capacitance. A single‐step methodology using a CO2laser system is developed for fabricating these electrodes under ambient conditions, providing an environmentally friendly alternative to conventional carbon sources. The resulting green micro‐supercapacitors (MSCs) achieve impressive areal capacitance (≈7–10 mF cm−2) and power and energy densities (≈4 μW cm‐2and ≈0.77 µWh cm−2at 0.01 mA cm−2). Stability tests conducted over 5000 charge–discharge cycles demonstrate a capacitance retention of ≈80–85%, highlighting the device durability. These LIG‐based devices offer versatility, allowing voltage output adjustment through stacked and sandwich MSCs configurations (parallel or series), suitable for various large‐scale applications. This study demonstrates that it is possible to create high‐quality energy storage devices based on biodegradable materials. This development can lead to progress in renewable energy and off‐grid technology, as well as a reduction in electronic waste.more » « less
-
The ever-growing demand for portable, bendable, twistable, and wearable microelectronics operating in a wide temperature range has stimulated an immense interest in the development of solid-state flexible energy storage devices using scalable fabrication technology. Herein, we developed additively manufactured graphene aerosol gel-based all-solid-state micro-supercapacitors (MSCs) via inkjet printing with functioning temperature in the range from −15 to +70 °C and exhibiting a super-stable and reliable electrochemical performance using interdigitated finger electrodes and PVA/H3PO4 solid-state electrolyte. The graphene aerosol gel was obtained using a scalable single step synthesis method from a gas phase precursor using a detonation process, producing a nanoscale shell type structure. The fabricated graphene aerosol gel-based solid-state MSC achieved a volumetric capacitance of 376.63 mF cm−3 (areal capacitance of 76.23 μF cm−2) at a constant current of 0.25 μA and demonstrated exceptional cyclic stability (∼99.6% of capacitance retention) over 10 000 cycles. To exploit the mechanical strength of the as-fabricated graphene aerosol gel-based solid-state MSC, its supercapacitive performance was scrutinized under various bending and twisting angles and the results showed excellent mechanical flexibility. Furthermore, to study the electrochemical performance of the as-fabricated graphene aerosol gel solid-state MSC in stringent surroundings, a broad temperature dependent supercapacitive analysis was performed as stated above. The electrochemical results of the as-fabricated graphene aerosol gel based all-solid-state MSC exhibit a highly potential route to develop scalable and authentic future miniaturized energy storage devices for IoT based smart electronic appliances.more » « less
-
Micro-supercapacitor is a member of the miniaturized energy storage device family, which offers great advantages on power density and life span. However, the limited device capacitance and narrow voltage window limit its energy density, hindering its application. In the present work, a novel micro-pseudocapacitor (MPC) constructed via the facile extrusion-based 3D printing technique has been demonstrated to deliver efficient charge storage with high device capacitance and moderate voltage window. Such an asymmetric MPC is constructed with 3D-printing-enabled asymmetric interdigitated cellular microelectrodes; in which, one is Ni–Co–O nanosheets grown on macroporous 3D reduced GO (3DG) microelectrode and the other is MnO 2 nanosheets grown on 3DG. Such an MPC offers facilitated fast electron transport, ionic diffusion, large number of active sites and desired porosity for electrolyte penetration. The asymmetric MPC shows a high specific capacity of 500 mC cm −2 , an energy density of 90 μW h cm −2 and a voltage window of 1.3 V. A device cycling stability with 10 000 charge and discharge cycles is also achieved for the as-fabricated asymmetric MPCs. These encouraging results may open a new avenue to design and fabricate state-of-the-art miniaturized electrochemical energy storage devices with customized geometries.more » « less
-
Abstract Electrochemical capacitors (ECs) offer superior specific capacitance for energy storage compared to traditional electrolytic capacitors but face limitations in alternating current (AC) filtering due to the need for balancing fast response and high capacitance. This study addresses these challenges by developing a freestanding nanostructured carbon electrode, derived from the rapid carbonization of bacterial cellulose (BC) embedded with zeolitic imidazolate framework 8 (ZIF‐8) and in situ formed carbon nanotubes (CNTs). The electrode exhibits an exceptionally low area resistance of 9.8 mΩ cm2and a high specific capacitance of 2.1 mF cm−2at 120 Hz, maintaining performance even at high frequencies. Stacking these electrodes enhances the capacitance to 5.3 mF cm−2, with the phase angle degrading to −74.4° at 120 Hz; however, they retain a phase angle below −45° up to ≈50 kHz, demonstrating excellent high‐frequency performance. Furthermore, connecting three aqueous units in series as an integrated cell or utilizing organic electrolytes extends the voltage window to 2.4 V, enhancing their suitability for high‐voltage applications. Ripple voltage analysis under various loads and frequencies indicates effective filtering capabilities, highlighting the potential of these nanostructured ECs for next‐generation electronic applications.more » « less
