Interwoven Carbon Nanotube Wires for High-Performing, Mechanically Robust, Washable, and Wearable Supercapacitors.

Abstract

An energy storage system with large storage capacity, rapid power release, and simultaneous tolerance to harsh mechanical stresses is a major bottleneck for realizing self-sustaining, wearable electronics. Addressing this, we demonstrate carbon nanotube wire (CNT-wire) interwoven solid-state supercapacitive energy storage devices (sewcaps) exhibiting superior storage capacity (30 Wh/kg, compared to electrochemical capacitors at ∼10 Wh/kg) and 14-fold higher power density (3511 W/kg) compared to Li-ion batteries (∼250 W/kg). While the high specific surface area and electrical conductivity of CNT-wires and high ionic conductivity of the electrolyte enable high energy density, the device design enables the combination of planar and radial diffusive pathways for ultralow interface resistance (∼0.2 mΩ/sewcap) and rapid charging-discharging ability (τ = 1.16 ms). Thus, this versatile approach of interweaving to form functional devices provides tunable power delivery across six orders of magnitude (2 μW to 2 W) through reconfiguration of the interweaving pattern and density. Importantly, such textile-integrated sewcaps exhibit unaltered performance (>95% retention across 4000 charge-discharge cycles) under extreme mechanical punishments such as repeated laundering, flexing (∼68°), rolling (360°), and crushing (∼21.8 kPa), implying direct interfacing with wearable platforms.