Research ArticleWEARABLE ELECTRONICS

Flexible and stretchable power sources for wearable electronics

See allHide authors and affiliations

Science Advances  16 Jun 2017:
Vol. 3, no. 6, e1602051
DOI: 10.1126/sciadv.1602051
  • Fig. 1 Fabrication of the compliant batteries.

    (A) The assembly flow diagram for the (B) flexible wire–shaped batteries achieved by shaping the current collector–electrode as a helical band spring and (C) stretchable serpentine-shaped batteries fabricated using the current collector of serpentine ribbon geometry.

  • Fig. 2 Electrochemical and mechanical characterization of the flexible wire battery.

    (A) Capacity per unit length (mA·hour cm−1) and coulombic efficiency (%) of silver-zinc wire battery cycled at 0.25C charge and 0.5C discharge rates between 1 and 1.8 V. (B) Galvanostatic charge-discharge curves for cycles 3, 30, and 90 of the battery in (A). (C) Specific capacity (mA·hour cm−1) and coulombic efficiency (%) of silver-zinc wire battery cycled between 1 and 1.8 V at charge rates C, 0.5C, and 0.25C and discharge rates 2C, C, and 0.5C, respectively. (D) Galvanostatic charge-discharge curves of the battery in (C). (E) Optical images of the flexible wire battery in a relaxed and deformed state. (F) Cycling performance of the battery operated in a flat configuration and while being continuously flexed to a bending diameter (D) of 1 cm.

  • Fig. 3 Electrochemical and mechanical performance of the stretchable batteries.

    (A) Specific capacity (mA·hour cm−1) and coulombic efficiency (%) of the battery that was first operated in a relaxed configuration (region I), stretched to 100% (region II) followed by cycling in a relaxed configuration (region III), and then subjected to five sets of 100 stretch cycles. Each set of 100 stretch cycles was alternated with one electrochemical cycle (region IV) followed by cycling in a relaxed configuration (region V). (B) Galvanostatic charge-discharge curves for the 2nd (flat configuration), 12th (stretched configuration), and 22nd (flat configuration) electrochemical cycles of the battery in (A). (C) Galvanostatic charge-discharge curves for the electrochemical cycles following the 1st, 100th, 200th, 300th, 400th, and 500th stretch cycles of the battery in (A). (D) Schematics of simple serpentine current collector and optical images of four serpentine-shaped batteries connected in series. Batteries continuously power an OLED while being subjected to uniaxial strain of 100%. (E) Schematics of self-similar serpentine current collector and optical images of the full battery assembled around such current collector. Geometry of the battery facilitates biaxial stretching.

  • Fig. 4 Integrated energy-harvesting and storage system.

    (A) Structure of organic photovoltaic module. (B and C) Current-voltage characteristics of four-cell OPV module under various indoor lighting conditions (B) and sunlight (C). (D) Images of photovoltaic module and wire battery integrated into a wearable bracelet. (E and F) Voltage and current during battery charging. OPV module is exposed to either CFL lighting with illuminance of 3000 lux (E) or sunlight (F). (G and H) Voltage, current, and cumulative stored charge of solar battery charging during a simulated day of use. Yellow shaded areas indicate periods of exposure to sunlight. White areas correspond to CFL lighting with illuminance of 300 (G) or 3000 lux (H).

Supplementary Materials

  • Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/3/6/e1602051/DC1

    fig. S1. The optical images for the serpentine ribbon current collectors stretched to 50, 100, 150, and 200% before and after releasing the stretch.

    fig. S2. Dimensions and optical images of the helical band spring and serpentine ribbon current collectors.

    fig. S3. SEM images of the wire battery components.

    fig. S4. SEM characterization of the thread-embedded silver electrode.

    fig. S5. The schematic of the custom-made flexing apparatus.

    fig. S6. Charge-discharge curves of the wire battery operated under continuous flexing conditions.

    fig. S7. Electrochemical cycling performance of the wire battery that was periodically stopped and flexed 1500 times in between the electrochemical cycles.

    fig. S8. A postmortem analysis of the wire battery.

    fig. S9. Performance characteristics of the 4-cm-long wire battery designed for integration with the solar module.

    fig. S10. Performance characteristics of the OPV module designed for integration with the wire battery.

    fig. S11. Power-voltage characteristics of the OPV module designed for integration with the wire battery.

    fig. S12. The schematic of the encapsulation of serpentine battery.

    fig. S13. Current-voltage characteristic of the particular OPV module used to charge the wire battery under sunlight.

    table S1. Performance parameters of single-OPV cells and four-cell modules under various lighting conditions.

    Supplementary Methods

  • Supplementary Materials

    This PDF file includes:

    • fig. S1. The optical images for the serpentine ribbon current collectors stretched to 50, 100, 150, and 200% before and after releasing the stretch.
    • fig. S2. Dimensions and optical images of the helical band spring and serpentine ribbon current collectors.
    • fig. S3. SEM images of the wire battery components.
    • fig. S4. SEM characterization of the thread-embedded silver electrode.
    • fig. S5. The schematic of the custom-made flexing apparatus.
    • fig. S6. Charge-discharge curves of the wire battery operated under continuous flexing conditions.
    • fig. S7. Electrochemical cycling performance of the wire battery that was periodically stopped and flexed 1500 times in between the electrochemical cycles.
    • fig. S8. A postmortem analysis of the wire battery.
    • fig. S9. Performance characteristics of the 4-cm-long wire battery designed for integration with the solar module.
    • fig. S10. Performance characteristics of the OPV module designed for integration with the wire battery.
    • fig. S11. Power-voltage characteristics of the OPV module designed for integration with the wire battery.
    • fig. S12. The schematic of the encapsulation of serpentine battery.
    • fig. S13. Current-voltage characteristic of the particular OPV module used to charge the wire battery under sunlight.
    • table S1. Performance parameters of single-OPV cells and four-cell modules under various lighting conditions.
    • Supplementary Methods

    Download PDF

    Files in this Data Supplement:

Navigate This Article