Self-powered electrochemical humidity sensor based on Cu/(cellulose nanocrystals/NaCl)/Zn structure for respiratory rate detection

Recently, the self-powered electrochemical humidity (ECH) sensors have received extensive attention. In this work, a self-powered ECH sensor is constructed based on cellulose nanocrystals (CNC)/NaCl humidity sensing material, and Cu and Zn electrodes. The results show that the proposed CNC/NaCl ECH sensor has good humidity sensing and power generation performances. Specifically, it has a wide humidity detection range (10.9 %–91.5 % relative humidity (RH)), fast response/recovery speed (27/22 s), and good linearity (41.1 %–91.5 % RH) at room temperature of 25 °C. A single CNC/NaCl ECH sensor can achieve high response voltage of 0.62 V, large short-circuit current (∼20 μA) and load power (∼4.48 μW) at 91.5 % RH. In addition, this work verifies the potential application of the CNC/NaCl ECH sensor in respiratory rate detection.