Cost‐Effective Hydrogen Sensor Employing a Quartz Crystal Tuning Fork

ABSTRACT Palladium has become one of the most hydrogen sensing systems due to its high affinity and selectivity for hydrogen. In this study, a commercially available quartz crystal, costing less than 0.1 US dollar, was used as a piezoelectric resonator. By removing the metal housing of the quartz crystal, a palladium (Pd) wire was bridged across the prongs of a quartz tuning fork (QTF), forming a Pd‐modified QTF. A quartz‐enhanced conductance spectroscopy (QECS) sensor system was then employed to evaluate the hydrogen sensor's performance. Benefiting from the hydrogen absorption of the palladium wire and the resonance amplification of the QTF, a detection sensitivity of 300 mHz/H 2 % was achieved. Finally, the potential application of the developed hydrogen sensor for the early warning of thermal runaway in lithium‐ion batteries was discussed.