A NEW POTENTIAL-TYPE HUMIDITY SENSOR USING EMD-BASED MANGANESE OXIDESAS A SOLID-ELECTROLYTE

A new approach for a potential-type humidity sensor is to use the batt ery systems M1/MnO(x)/M2 as the sensing elements, where M1/M2 are two electrodes of different metals, and MnO(x) samples act as the solid el ectrolyte. Systems consisting of MnO2 electrolytes with Pt/Cu electrod es are most favorable for obtaining high electrical potentials in a hi gh ambient humidity. However, the humidity response characteristics of these systems can be greatly improved by mixing a certain amount of M n3O4 into the MnO2 electrolyte materials. For all systems, the potenti al value produced between the Pt/Cu couple tends to equal the sum of t hose produced between the Pt/Ni and the Cu/Ni couples. A simple model is proposed to interpret the phenomena.