Emerging electrochemical humidity sensors for zero power consumption and self-powered humidity detection: a perspective

Electrochemical humidity (ECH) sensor integrated humidity sensing and power generation functions not only can spontaneously output humidity sensing voltage and achieve zero power consumption (excitation voltage free), but also have the high output power potential of a battery, which is expected to power other electronic devices in the circuit system, receiving widespread attention in the field of power generation humidity sensors. However, there are still the following issues with the ECH sensor: (1) the working principle is not yet clear and even controversial; (2) the humidity sensing and power generation performances need to be improved; (3) a self-powered humidity detection system needs to be realized. This perspective aims to provide an overview of the ECH sensor based on the above issues. In addition, insights and solutions are proposed to address the current issues faced by the ECH sensor in terms of mechanisms, materials, structures, performances and applications. With this perspective article, the basic research and practical applications of the ECH sensor with zero power consumption and self-powered potential are expected to make significant progress in the future. This perspective summarizes recent advances in electrochemical humidity sensors and mainly focuses on three aspects: working principles; humidity sensing and power generation performances; self-powered humidity detection system.