Symmetrical MnO₂–Carbon Nanotube–Textile Nanostructures for Wearable Pseudocapacitors with High Mass Loading

While MnO(2) is a promising material for pseudocapacitor applications due to its high specific capacity and low cost, MnO(2) electrodes suffer from their low electrical and ionic conductivities. In this article, we report a structure where MnO(2) nanoflowers were conformally electrodeposited onto carbon nanotube (CNT)-enabled conductive textile fibers. Such nanostructures effectively decrease the ion diffusion and charge transport resistance in the electrode. For a given areal mass loading, the thickness of MnO(2) on conductive textile fibers is much smaller than that on a flat metal substrate. Such a porous structure also allows a large mass loading, up to 8.3 mg/cm(2), which leads to a high areal capacitance of 2.8 F/cm(2) at a scan rate of 0.05 mV/s. Full cells were demonstrated, where the MnO(2)-CNT-textile was used as a positive electrode, reduced MnO(2)-CNT-textile as a negative electrode, and 0.5 M Na(2)SO(4) in water as the electrolyte. The resulting pseudocapacitor shows promising results as a low-cost energy storage solution and an attractive wearable power.