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Real-time, daily health monitoring can provide large amounts of patient data, which may greatly improve the likelihood of diagnosing health conditions at an early stage. One potential sensor is a flexible humidity sensor to monitor moisture and humidity information such as dehydration. However, achieving a durable functional nanomaterial-based flexible humidity sensor remains a challenge due to partial desorption of water molecules during the recovery process, especially at high humidities. In this work, we demonstrate a highly stable resistive-type Pd/HNb3O8 humidity sensor, which exhibits a perdurable performance for over 100 h of cycle tests under a 90% relative humidity (RH) without significant performance degradation. One notable advantage of the Pd/HNb3O8 humidity sensor is its ability to regulate hydroniums due to the strong reducibility of H atoms dissociated on the Pd surface. This feature realizes a high stability even at a high humidity (99.9% RH). Using this superior performance, the Pd/HNb3O8 humidity sensor realizes wireless monitoring of the changes in the fingertip humidity of an adult under different physiological states, demonstrating a facile and reliable path for dehydration diagnosis.

Unlike common TMDCs such as MoS2, PtSe2 can be fabricated at temperatures below 600 °C, or even as low as 300 °C, while still maintaining high quality. By varying the selenization temperature from 300 °C to 600 °C, the electrical properties were changed significantly, resulting in superior gas sensing performance. Through comprehensive material analysis, an interesting phenomenon was found, namely that strain along the [001] direction existed in films grown at a low temperature rather than at a high temperature. Moreover, due to the layer-dependent property of PtSe2, a phase transition from metal-to-semiconductor occurs as the thickness is reduced. Hybridization of phase engineering and thermal strain engineering significantly enhances the gas sensing performance, resulting in PtSe2 with a dramatic increase in the response to 1 ppm NO2 from 25% to 550% once the thickness was reduced from 10 to 5 layers. In addition, PtSe2 showed good stability during exposure to not only 1 ppm but also 50 ppb NO2 for more than 5 cycles with responses of over 550% and 60%, respectively.

Non-layered e-Ti2N with a work function of ∼4.75 eV, synthesized by a rapid process assisted by N2 plasma immersion, is successfully applied as the anode material of lithium-ion batteries with good performance; it exhibits discharge capacity of ∼450 mA h g−1, which is close to the theoretical value, coulombic efficiencies of >85%, and capacity retentions (≥80%).