A bioinspired microdevice unifying energy storage and actuation through hydration control.

Area of Science:

• Materials Science
• Polymer Chemistry
• Energy Storage
• Microactuation

Background:

• Biological systems integrate energy storage and actuation, unlike synthetic systems which use separate components.
• Conjugated polymers can combine energy storage and actuation but face performance-stability trade-offs due to ion insertion and water uptake.
• Anion hydration within the polymer backbone is a key factor influencing this trade-off.

Purpose of the Study:

• To investigate the role of anion hydration in governing the performance-stability trade-off in conjugated polymers.
• To develop a strategy for enhancing the integration of energy storage and actuation in microscale devices.
• To demonstrate a novel monolithic device leveraging controlled anion hydration.

Main Methods:

• Utilized in-operando Raman spectroscopy to monitor polymer behavior during operation.
• Employed time-resolved mass measurements to quantify water ingress and mass changes.
• Manipulated anion hydration levels to alter polymer response and stability.

Main Results:

• Reducing anion hydration suppressed water ingress and mitigated polymer backbone degradation.
• Controlled hydration shifted the polymer response from a two-step swelling to a single, rapid volumetric relaxation.
• A monolithic sub-millimeter device integrated energy storage (161 mAh cm⁻²) and actuation, reducing actuator energy consumption by fourfold.

Conclusions:

• Anion hydration is a critical design parameter for multifunctional conjugated polymer devices.
• Controlling anion hydration enables simultaneous optimization of performance and stability in energy storage and actuation.
• This approach offers significant promise for developing advanced integrated energy-motion architectures at the microscale.