Stretchable, weavable coiled carbon nanotube/MnO2/polymer fiber solid-state supercapacitors.

Changsoon Choi,Youn Tae Kim,A Young Choi,Hyeon Jun Sim,Xavier Lepró,Shi Hyeong Kim,Seon Jeong Kim,Geoffrey M Spinks,Ray H Baughman,Jae Ah Lee

doi:10.1038/srep09387

Abstract

Fiber and yarn supercapacitors that are elastomerically deformable without performance loss are sought for such applications as power sources for wearable electronics, micro-devices, and implantable medical devices. Previously reported yarn and fiber supercapacitors are expensive to fabricate, difficult to upscale, or non-stretchable, which limits possible use. The elastomeric electrodes of the present solid-state supercapacitors are made by using giant inserted twist to coil a nylon sewing thread that is helically wrapped with a carbon nanotube sheet, and then electrochemically depositing pseudocapacitive MnO2 nanofibers. These solid-state supercapacitors decrease capacitance by less than 15% when reversibly stretched by 150% in the fiber direction, and largely retain capacitance while being cyclically stretched during charge and discharge. The maximum linear and areal capacitances (based on active materials) and areal energy storage and power densities (based on overall supercapacitor dimensions) are high (5.4 mF/cm, 40.9 mF/cm2, 2.6 μWh/cm2 and 66.9 μW/cm2, respectively), despite the engineered superelasticity of the fiber supercapacitor. Retention of supercapacitor performance during large strain (50%) elastic deformation is demonstrated for supercapacitors incorporated into the wristband of a glove.

Highlights

Fiber and yarn supercapacitors that are elastomerically deformable without performance loss are sought for such applications as power sources for wearable electronics, micro-devices, and implantable medical devices
Commercial available metal wires having high electrical conductivity has been used as electrodes for fiber supercapacitor[2,3], but their inborn rigidity restrict their use in textiles to store energy for wearable electronics
Carbon nanotube aerogel sheet ribbons, which were continuously drawn from a carbon multiwalled nanotube (MWNT) forest[9], were helically wrapped around the nylon fibers to provide the electronically active fiber electrode component (Supplementary Fig. S1b)

Summary

Introduction

Fiber and yarn supercapacitors that are elastomerically deformable without performance loss are sought for such applications as power sources for wearable electronics, micro-devices, and implantable medical devices. Wet-spun graphene/CNT composite fibers provide highly enhanced specific capacitances due to component synergy[6,7], but contain costly carbon single walled nanotubes[7] and break at ,10% strain[6]. Such limited stretchability of these variously proposed fiber electrodes for supercapacitors may restrict use in advanced applications, like effective power sources for artificial muscles[10] or highly stretchable electronics[11]. Buckled[12] and spring fiber[13] electrodes have been effectively deployed for highly stretchable film/fiber type energy storage devices, realizing high stretchability, low cost, and scalability for one-dimensional fiber and fiber supercapacitors remain still challenging

Methods

Results

Conclusion