Giant piezoionic effect of ultrathin MXene nanosheets toward highly-sensitive sleep apnea diagnosis

Flexible piezoionic sensors are emerging as an important platform for non-invasive human health detections. But it keeps a long way toward applications because of the weak piezoionic effects of general sensing materials. Here, we report giant piezoionic effect of ultrathin MXene nanosheets, which is enabled by abundant ion channels and strong ionic affinity. The flexible sensor delivers a high piezoionic signal of 219 mV, which significantly exceeds those of the best-known piezoionic materials. It displays superior working stability with signal retention of 98% even after 10,000 cycles under ambient conditions. The piezoionic sensors display high sensitivity for recognising physiological signals of human body, including wrist bendings, exercise modes, and pulse vibrations. Especially, sleep apnea diagnosis, which is vital for sleep-related disease, can be real-time detected accurately and reliably based on the flexible sensors. The discovery of giant piezoionic effects for sensitive health detections will accelerate development of smart medical instruments.

Automated summary

Flexible piezoionic sensors are being recognized as an important tool for non-invasive human health monitoring. The discovery of giant piezoionic effects in ultrathin MXene nanosheets has provided a solution to the weak piezoionic effects in general sensing materials. These sensors show high sensitivity for physiological signals and can accurately detect sleep apnea in real-time, which is crucial for sleep-related disorders. The development of smart medical instruments will be accelerated with the advancement of sensitive health detection using giant piezoionic effects.