Humidity-Resistant Hydrogen Sulfide Sensor Based on Dense Tangled Gel Armor in Dynamic Environments

Accurate detection of hydrogen sulfide in high-humidity environments is critical for applications ranging from oral pathology via breath analysis to industrial safety monitoring. However, conventional sensors suffer severe signal drift and electrode degradation under humidity above 90%, impeding reliable operation in real-world scenarios. Here, we present a self-powered, humidity-resistant sensor using a primary battery architecture coupled with a densely tangled hydrogel electrolyte. The sensing principle relies on non-faradaic adsorption-induced modulation of the Ag electrode potential. By precisely engineering polymer entanglement density, we create a hydrophobic gel armor that suppresses moisture penetration, confining signal drift to 14.68% at 95% relative humidity. This mechanism enables an ultra-low detection limit of 0.029 ppb, a high specificity of 98.7% against common interferents, and robust mechanical flexibility under 30% strain. The device integrates into portable, Bluetooth-enabled platforms for distributed monitoring across applications including clinical breath analysis, food spoilage detection, and underwater pipeline leak inspection.