Battery-Sensor Hybrid: A New Gas Sensing Paradigm with Complete Energy Self-Sufficiency.

Fully autonomous operation has long been an ultimate goal in environmental sensing. Although self-powered gas sensors based on energy harvesting have been widely reported to provide power for autonomous operation, these sensors rely on external sources of harvestable energy, thus are not completely self-sufficient. Herein, a battery-sensor hybrid device that can simultaneously function as both a power source and a gas sensor is presented. The battery-sensor consists of a cathode that reduces NO2 to NO2- via a catalyst with Fe-Nx species distributed on highly graphitic porous nitrogen-doped carbon. On the basis of the efficient and selective electrocatalytic activity of the catalyst, the battery-sensor is capable of sensing NO2 and does so without any external power, overcoming the long-standing grand challenge to achieve complete energy self-sufficiency. Furthermore, through controlling the working current the sensing range can be significantly expanded and electronically tuned, which is not only unprecedented for gas sensors but also of remarkable commercial practicality. The proposed battery-sensor hybrid architecture represents a new paradigm toward sensors with complete energy self-sufficiency.