Encapsulated, High-Performance, Stretchable Array of Stacked Planar Micro-Supercapacitors as Waterproof Wearable Energy Storage Devices

Hyoungjun Kim, Jangyeol Yoon, Geumbee Lee, Seung Ho Paik, Gukgwon Choi, Daeil Kim, Beop-Min Kim, Goangseup Zi, Jeong Sook Ha

Research output: Contribution to journalArticle

51 Citations (Scopus)

Abstract

We report the fabrication of an encapsulated, high-performance, stretchable array of stacked planar micro-supercapacitors (MSCs) as a wearable energy storage device for waterproof applications. A pair of planar all-solid-state MSCs with spray-coated multiwalled carbon nanotube electrodes and a drop-cast UV-patternable ion-gel electrolyte was fabricated on a polyethylene terephthalate film using serial connection to increase the operation voltage of the MSC. Additionally, multiple MSCs could be vertically stacked with parallel connections to increase both the total capacitance and the areal capacitance owing to the use of a solid-state patterned electrolyte. The overall device of five parallel-connected stacked MSCs, a microlight-emitting diode (μ-LED), and a switch was encapsulated in thin Ecoflex film so that the capacitance remained at 82% of its initial value even after 4 d in water; the μ-LED was lit without noticeable decrease in brightness under deformation including bending and stretching. Furthermore, an Ecoflex encapsulated oximeter wound around a finger was operated using the stored energy of the MSC array attached to the hand (even in water) to give information on arterial pulse rate and oxygen saturation in the blood. This study suggests potential applications of our encapsulated MSC array in wearable energy storage devices especially in water.

Original languageEnglish
Pages (from-to)16016-16025
Number of pages10
JournalACS Applied Materials and Interfaces
Volume8
Issue number25
DOIs
Publication statusPublished - 2016 Jun 29

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Keywords

  • encapsulation
  • liquid metal
  • micro-supercapacitor
  • oximeter
  • stretchable
  • waterproof

ASJC Scopus subject areas

  • Materials Science(all)

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