This paper reviews the research progress on ionogels in flexible pressure sensors. Ionogels comprise solid carrier networks and ionic liquids (ILs) dispersed therein and have good non-volatility, high conductivity, thermal stability, a wide electrochemical window, and mechanical properties. These characteristics give ionogels broad application prospects in wearable electronic devices, intelligent robots, and healthcare. The article first introduces the classification of ionogels, including the classification based on ILs and solid carrier networks. Then, the preparation methods and processing technologies of ionogels, such as the direct mixing method, in situ polymerization/gel method, and solvent exchange method, are discussed. Subsequently, the article expounds in detail on the properties and modification methods of ionogels, including toughness, conductivity, hydrophobicity, self-healing, and adhesiveness. Finally, the article focuses on the application of ionogels in flexible pressure sensors and points out the challenges faced in future research. The language of this mini-review is academic but not overly technical, making it accessible to even researchers new to the field and establishing an overall impression of research. We believe this mini-review serves as a solid introductory resource for a niche topic, with large and clear references for further research.

Chemical warfare agents (CWAs) are known as poor man’s bombs because of their small lethal dose, cheapness, and ease of production. Therefore, the highly sensitive and rapid detection of CWAs at room temperature (RT = 25 °C) is essential. In this paper, we have developed a resistive semiconductor sensor for the highly sensitive detection of CWAs at RT. The gas-sensing material is SnS₂/rGO nanosheets (NSs) prepared by hydrothermal synthesis. The lower detection limits of the SnS₂/rGO NSs-based gas sensor were 0.05 mg/m³ and 0.1 mg/m³ for the typical chemical weapons sarin (GB) and sulfur mustard (HD), respectively. The responsivity can reach −3.54% and −10.2% in 95 s for 1.0 mg/m³ GB, and in 47 s for 1.0 mg/m³ HD. They are 1.17 and 2.71 times higher than the previously reported Nb-MoS₂ NSs-based gas sensors, respectively. In addition, it has better repeatability (RSD = 6.77%) and stability for up to 10 weeks (RSD = 20.99%). Furthermore, to simplify the work of later researchers based on the detection of CWAs by two-dimensional transition metal sulfur compounds (2D-TMDCs), we carried out calculations of the SnS₂ NSs-based and SnS₂/rGO NSs-based gas sensor-adsorbing CWAs. Detailed comparisons are made in conjunction with experimental results. For different materials, it was found that the SnS₂/rGO NSs-based gas sensor performed better in all aspects of adsorbing CWAs in the experimental results. Adsorbed CWAs at a distance smaller than that of the SnS₂ NSs-based gas sensor in the theoretical calculations, as well as its adsorption energy and transferred charge, were larger than those of the SnS₂ NSs-based gas sensor. For different CWAs, the experimental results show that the sensitivity of the SnS₂/rGO NSs-based gas sensor for the adsorption of GB is higher than that of HD, and accordingly, the theoretical calculations show that the adsorption distance of the SnS₂/rGO NSs-based gas sensor for the adsorption of GB is smaller than that of HD, and the adsorption energy and the amount of transferred charge are larger than that of HD. This regularity conclusion proves the feasibility of adsorption of CWAs by gas sensors based on SnS₂ NSs, as well as the feasibility and reliability of theoretical prediction experiments. This work lays a good theoretical foundation for subsequent rapid screenings of gas sensors with gas-sensitive materials for detecting CWAs.