Wearable Energy Storage with MXene Textile Supercapacitors for Real World Use

Successful implementation of wearable electronics requires practical wearable energy storage systems that can meet certain power and energy metrics. However, flexible, stretchable, and truly textile-grade energy storing platforms have so far remained missing from most e-textile systems due to the insufficient performance metrics of current available materials and technologies. Two-dimensional (2D) transition metal carbides and nitrides (MXenes) offer unique combinations of properties including metallic conductivity, high specific capacitance, hydrophilicity, and solution processability, as well as mechanical flexibility and robustness that render these materials promising for flexible wearable energy storage technologies. Here we demonstrate textile-based electrochemical capacitor devices with high areal loading of Ti₃C₂T<i>_x</i> that can be integrated in series via a stacked design approach and meet the real-world power requirements for wearable electronics. A demo textile supercapacitor with 5 cells in series and a footprint area of 25 cm² and a MXene loading of 24.2 mg cm^-2 could operates in a 6 V voltage window delivering an energy density of 0.401 mWh cm^-2 at a power density of 0.248 mW cm^-2, and an areal capacitance of 146 mF cm^-2 at a 0.16 mA cm^-2discharge current. The MXene textile supercapacitor powers a temperature monitoring system requiring high current densities with wireless data transmission to a receiver for 96 minutes. This initial report of a MXene textile supercapacitor powering a practical peripheral electronics system demonstrates the potential of this family of 2D materials to support a wide range of devices such as motion trackers and biomedical monitors in a flexible textile form factor.