A potentiometric SO₂ gas sensor based on the Li₃PO₄-Li₂SiO₃ solid electrolyte thin film

Area of Science:

• Electrochemistry
• Materials Science
• Chemical Sensing

Background:

• Development of solid-state electrochemical sensors for gas detection is crucial for environmental monitoring and industrial safety.
• Potentiometric sensors offer advantages in selectivity and long-term stability for gas analysis.

Purpose of the Study:

• To develop and characterize a novel potentiometric sulfur dioxide (SO2) gas sensor.
• To investigate the performance of a Li3PO4-Li2SiO3 solid electrolyte thin film in a SO2 sensing application.

Main Methods:

• Fabrication of a thin film solid electrolyte using RF magnetron sputtering.
• Construction of a galvanic cell sensor with gold electrodes and a Li2SO4-V2O5 sensing layer doped with TiO2 and MgO.
• Testing sensor response and recovery characteristics at various temperatures (400-500 °C) and SO2 concentrations.

Main Results:

• The sensor exhibited good response to SO2 at temperatures between 400-450 °C.
• Optimal doping of the sensing electrode (Li2SO4:TiO2 at 1:1 mol ratio with 5 wt.% V2O5 and 5 wt.% MgO) yielded favorable characteristics.
• Achieved sensitivity ranged from 90.15 to 57.19 mV/dec, with response/recovery times of 20-40 s and 2.5-4 min, respectively.

Conclusions:

• The developed potentiometric SO2 sensor based on Li3PO4-Li2SiO3 solid electrolyte demonstrates promising performance for gas detection.
• The sensor shows good sensitivity and stability, with performance approaching theoretical values at 425 °C.