Humidity sensitive property of Li-doped mesoporous silica SBA-15

Mesoporous silica SBA-15 was synthesized by a sol–gel method, and different level of LiCl was doped into SBA-15 by heat-treating process at 550 °C to form a series of samples. These samples and pure SBA-15 were investigated as humidity sensor materials at room temperature within the relative humidity range of 11–95%. It was found that after the doping of LiCl, the humidity sensitivity has been greatly improved, the impedance changed by more than three orders of magnitude over the whole humidity range. This was related to the hydrophilic property of the Li+, and a possible mechanism was provided to explain the humidity sensitive properties.