Porous Ion Gel: A Versatile Ionotronic Sensory Platform for High-Performance, Wearable Ionoskins with Electrical and Optical Dual Output

Abstract

The development of elastic ionic conductors offers opportunities to fabricate key wearable ionic components such as ionoskins that can perceive mechanical deformation. However, there is still plenty of room to overcome the trade-off between sensitivity and detectable range of previous systems and impart additional functionality. Here, we propose porous ion gels for high-performance, functional ionic sensory platforms. The porous ion gels can be effectively deformed by closing pores even with a small pressure, and a large change in the contact area of the gel and the electrode is induced, leading to a significant difference in electrical doublelayer capacitance. The porous ion gels are applied to ionoskins after optimizing mechanical characteristics by adjusting gel parameters. The device indicates a high sensitivity of ∼152.8 kPa −1 , a broad sensory pressure range (up to 400 kPa), and excellent durability (>6000 cycles). Successful monitoring of various human motions that induce different magnitudes of pressure is demonstrated with high precision. More interestingly, the functionality of the porous ion gel is extended to include electrochemiluminescence (ECL), resulting in the production of emissive ECL ionoskins. The ECL intensity from the emissive ionoskin is linearly correlated with the applied pressure, which can even be inferred even by the naked eye. The porous ion gel-based functional ionoskins are expected to be key components in future sensory ionotronics.

Flexible Pseudocapacitive Iontronic Tactile Sensor Based on Microsphere‐Decorated Electrode and Microporous Polymer Electrolyte for Ultrasensitive Pressure Detection

“…[29][30][31] To overcome the obstacles, building microstructures in dielectrics [31,32] or electrodes [33][34][35] have been proved to be an effective approach and have been successfully validated in various topographical microstructures including the artificial micropyramid, [36,37] microwrinkles, [38] microdomes, [39] and micropillars [40,41] as well as other structures directly molded from bionic patterns on the morphological surfaces of leave and flower petals. [42,43] However, limitations still exists: 1) due to the easily saturated effective contacting area, the microstructures reported are only effective for a low pressure detection range (typically less than 10 kPa); [44][45][46] 2) the fabrication of such artificial microstructures requires the use of high precise but expensive equipment (e.g., lithography machine) and complicated processes; [47] 3) the preparation of such bionic microstructures lacks uniformity within one single device and among different devices. [2] Therefore, a facile and efficient fabrication strategy of constructing microstructures in key components of tactile sensors to obtain enhanced sensing performance is still highly desired.…”

Ionic Liquid-Based Gels for Applications in Electrochemical Energy Storage and Conversion Devices: A Review of Recent Progress and Future Prospects

“…IL-based gels, which are composed of polymeric gelators and ILs, are another potential platform that can offer many possible approaches, with vast research scopes. The properties of the co-polymer gelators are a critical parameter that is directly related to gel performance [ 57 , 58 , 59 , 60 , 61 ]. Gelation should be accomplished with the lowest quantity of polymer possible to generate highly conductive gels.…”

“…Gelation should be accomplished with the lowest quantity of polymer possible to generate highly conductive gels. Thus, coherent molecular design is required to include both IL-soluble and IL-insoluble components [ 59 , 60 , 61 ]. When combined with IL, the IL-soluble segments swell, forming ion conductive channels, while the components that are insoluble in ILs aggregate to limit enthalpically unfavorable interaction with the ILs.…”

“…When combined with IL, the IL-soluble segments swell, forming ion conductive channels, while the components that are insoluble in ILs aggregate to limit enthalpically unfavorable interaction with the ILs. Various copolymers such as block [ 62 , 63 , 64 , 65 ], star [ 57 , 58 ], and random [ 59 , 60 , 61 ] types of ion gel have been proposed based on these requirements.…”

High-Porosity Foam-Based Iontronic Pressure Sensor with Superhigh Sensitivity of 9280 kPa−1

“…First, although the dielectric layer made of foam material may improve the sensitivity to some extent, the thickness-governed sensing mechanism limits the potential sensitivity peak [ 26 , 27 ]. For another, structural parameters, such as porosity or elastic modulus of foams, have not been received enough attention in iontronic sensors that based on contact area-governed sensing mechanism [ 28 ]. Therefore, determining how to combine the advantages of ionic material and foam architecture is an open question.…”