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We report a thin film wearable aluminum-air battery that utilizes the flow of a biological fluid (eye tear) as a moving electrolyte. When the eye blinks, the eye-tear fluid comes into contact with two metal electrodes, and it produces spontaneous redox reactions, which generate an electric current when connected to a load. In this paper, we demonstrate that a 5×5 mm2 tear-activated Al-air battery is capable of providing maximum energy of 45 μJ per eyeblinking cycle. Furthermore, we investigate the effect of different air-breathing electrodes, including gold, platinum, and silver, on the battery's performance. Results demonstrate that the battery's maximum voltage and current outputs are 1 V and 220 μA while using Pt as the cathode. The moving biofluid Al-air battery with the Pt cathode charges up a 10 μF capacitor in 10 s. Furthermore, load line analysis shows a maximum deliverable load power density of 64 μW·cm-2 for this device.
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Eye Tear Activated Mg‐Air Battery Driven by Natural Eye Blinking for Smart Contact Lenses
Abstract A sliding electrolyte metal‐air microbattery driven by natural eye blinking motion is demonstrated as a source of electrical energy that can be integrated with smart contact lens platforms. The metal‐air battery (footprint 10 mm2) consists of a Mg anode and a Pt cathode, patterned on an insulating substrate and the battery electrolyte is a film of eye‐tear fluid that is periodically dragged on top of the electrodes during the natural eye‐blinking cycle, which activates the battery. When tested with an eye emulator, the open‐circuit voltage across the eye‐tear activated metal‐air battery (ETMAB) is 2.2 V. Impedance matching analysis reveals a maximum battery‐specific capacity of 3561 mAh g–1obtained at a discharge current density of 5 mA cm–2. The blinking activated battery exhibits the maximum generated power density of 1.3 mW cm–2at the load of 740 Ω. The blinking ETMAB delivers eight times higher energy output and more than three times longer lifetime than achievable with static ETMAB designs.
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- Award ID(s):
- 1932602
- PAR ID:
- 10390656
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Advanced Materials Technologies
- Volume:
- 8
- Issue:
- 1
- ISSN:
- 2365-709X
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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