Novel coaxial fiber-shaped sensing system integrated with an asymmetric supercapacitor and a humidity sensor

A high-performance fiber-shaped integrated multifunctional sensing system was designed and fabricated based on flexible fiber-shaped supercapacitors (FFSCs) and humidity sensors. A facile and cost-effective method was proposed to grow three-dimensional MnO2 nanoballs (NBs)@Ni cone/carbon nanotube (CNT) film with a high specific capacitance of 609.06 mF cm−2 at a current density of 0.5 mA/cm2. In addition, asymmetric coaxial FFSCs (ACFFSCs) with a maximum operating voltage of 1.8 V were assembled by wrapping MnO2 NBs@Ni cone/CNT film on MoS2 nanosheet arrays/carbon nanotube fibers as the inner and outer electrodes of the ACFFSCs device, respectively, with poly(vinyl alcohol)/KOH as the gel electrolyte. The assembled ACFFSCs device embraces a high specific capacitance of 195.38 mF cm−2, and a superior areal energy density of 83.59 μWh cm−2. Moreover, the ACFFSCs device acts as the stable power supply for the coaxial fibrous humidity sensor, and the obtained flexible humidity sensing system possesses high sensitivity (2.483/%RH) in the detection of relative humidity (RH), with a fast response speed of 0.39 s.