Microsupercapacitors

Microsupercapacitors (MSCs) are attractive energy storage devices for integration into small microsystems such as IoT motes, wireless sensors, and wearables. Unlike batteries, they offer high power density, rapid charge/discharge, and virtually unlimited cycle life, making them ideal complements or replacements for micro-batteries in untethered microelectronic platforms.

At LAFT, we pursue the creation of 100% additively manufactured microsupercapacitors — devices with footprints below 1 cm² — by systematically refining multi-component chemistries and device geometry to maximize electrochemical performance. Our approach combines extrusion-based 3D printing (FDM) with direct-write printing of functional inks, enabling full integration of electrodes, electrolyte, current collectors, packaging, and encapsulation without any cleanroom processing.

World-Record Fully Integrated Additively Fabricated MSCs

In our first generation of fully integrated printed MSCs, we demonstrated millimeter-scale devices (full package: 7 mm × 7 mm; active area: 4 mm × 3.5 mm; total height ~2 mm) with exceptional electrochemical performance. By carefully optimizing the chemistries of every component — electrodes, electrolyte, and current collectors — we achieved an areal capacitance of ~323 mF cm⁻², energy density of 16.1 µWh cm⁻², power density of ~3028 mW cm⁻², and ~91.3% capacitance retention after 21,000 cycles. These are among the highest performance levels reported for fully integrated, fully additively manufactured MSCs. [Hodaei & Subramanian, Journal of Power Sources, 2023]

Sub-mm³ Dimensional Scaling for Chip-Scale Embedding

Building on this foundation, we systematically investigated dimensional scaling of fully integrated additively fabricated MSCs down to the sub-mm³ volume range, making them candidates for chip-scale embedding in microelectronics. By varying electrode length and cross-section, we studied the tradeoffs between capacitance, energy density, and power density across a range of device geometries.

Fabrication steps of additively manufactured microsupercapacitors: (A) silver current collector printing, (B) FDM PCL package, (C) electrode printing, (D) electrolyte deposition, (E) packaged device, (F) dimensional scaling design, (G-H) top and side view photos of a completed device.
Fig. 1 — Fabrication process and dimensional scaling of additively manufactured MSCs. Panels A–E show the sequential printing steps; panels F–H show the scaling design and optical images of a completed sub-mm³ device. Reproduced from Hodaei & Subramanian, J. Mater. Chem. A, 2024, 12, 10229 under CC BY 3.0.

Our scaled devices achieved a maximum areal capacitance of ~731.7 mF cm⁻², areal energy density of ~36.59 µWh cm⁻², areal power density of ~2669.8 mW cm⁻², and ~95% capacitance retention after 17,000 cycles — the highest values reported to date for such systems. In volumetric terms, these devices reached 8.7 F cm⁻³ (capacitance), 0.436 mWh cm⁻³ (energy density), and 31.78 W cm⁻³ (power density).

Electrochemical characterization of microsupercapacitors: cyclic voltammetry and galvanostatic charge-discharge curves for devices with different electrode thicknesses and lengths.
Fig. 4 — Electrochemical performance of scaled MSCs. Cyclic voltammetry and galvanostatic charge–discharge profiles as a function of electrode geometry, demonstrating the scalability of capacitance and energy storage. Reproduced from Hodaei & Subramanian, J. Mater. Chem. A, 2024, 12, 10229 under CC BY 3.0.

These results were enabled by a novel nanocomposite electrode based on edge-oxidized graphite oxide (EOGO) and cerium oxide nanoparticles, a UV-curable PEGDA/LiCl hydrogel electrolyte, and a silver paste current collector. Devices are fully packaged using 3D-printed polycaprolactone (PCL) and a UV-curable resin encapsulant. [Hodaei & Subramanian, Journal of Materials Chemistry A, 2024]

Ragone plot comparing the energy and power density of LAFT additively fabricated microsupercapacitors against the state of the art in the literature.
Fig. 7 — Ragone plot benchmarking LAFT’s additively fabricated MSCs against the state of the art. Our devices achieve simultaneously high energy and power densities, placing them at the forefront of reported performance for fully integrated printed MSCs. Reproduced from Hodaei & Subramanian, J. Mater. Chem. A, 2024, 12, 10229 under CC BY 3.0.

Affiliated Member

Amin Hodaei

Key Publications

  • A. Hodaei, V. Subramanian, “Sub-mm³ dimensional scaling of fully-integrated additively-fabricated microsupercapacitors for embedded energy storage applications,” Journal of Materials Chemistry A, 12, 10229–10241, 2024. DOI: 10.1039/D3TA07159F
  • A. Hodaei, V. Subramanian, “Additive fabrication of fully-integrated high-performance millimeter-scale microsupercapacitors: Fine-tuning chemistry to maximize performance,” Journal of Power Sources, 588, 233738, 2023. DOI: 10.1016/j.jpowsour.2023.233738