Green synthetic PPy/MXene-based cotton fabric hydrovolt generators for self-powered wearables

Harvesting energy from naturally abundant water resources is expected to alleviate the need for the current energy shortage. However, existing studies rarely consider the effect of capacitors on the output of hydropower generation. Here, inspired by capacitors, we prepared a flexible and efficient hydrovoltaic generator by loading polypyrrole (PPy) and Ti₃C₂Tx MXene onto cotton fabrics by a simple green one-step synthesis method with self-assembly. Specifically, the ionic imbalance at the interface can be exacerbated by the use of expanded capacitance, while synergistically the two materials PPy/MXene will adsorb different ions, which promotes efficient adsorption of ions and ensures energy conversion. This generator can produce an open-circuit voltage (V_OC) of 0.35 V and a short-circuit current (I_SC) of ~260 microA in just 5 mL of a 3.5 wt% NaCl solution, and the optimized device can achieve an output power of 35.76 microW. Furthermore, this capacitance-enhanced fabric-based hydrovolt generator can directly power electronic devices and demonstrates its potential future applications in practical applications such as respiratory monitoring and touch sensing.