Benefiting from the ultrahigh capacitance of electric double layer interfaces, iontronic sensors have emerged as a powerful platform for mechanical sensing, offering exceptional sensitivity, strong immunity to electromagnetic interference, and robust signal stability. Despite rapid advances in materials, structural design, and interfacial engineering, the fundamental electrical parameters that govern ion transport and electric double layer formation, i.e. ionic conductivity and excitation frequency, have remained largely unexplored in a systematic and quantitative manner.
A research team led by Jin Ge at Sun Yat-Sen University in Guangzhou, China, has now addressed this gap by elucidating how these two intrinsic parameters dictate iontronic pressure-sensing performance, providing a practical and scalable strategy for developing high-sensitivity tactile sensors for next-generation human–machine interfaces.
The team reported their research findings in Nano Research on June 8, 2026
"In this work, we established an ionic droplet-based model system to decouple and analyze the roles of ionic conductivity and excitation frequency," said Jin Ge, corresponding author of the study and professor at the School of Chemistry, Sun Yat-Sen University. "By combining electrochemical impedance spectroscopy with equivalent circuit modeling, we quantitatively correlated device impedance and apparent capacitance variation with these parameters. Our results reveal that capacitance variation is enhanced by lowering ionic conductivity and increasing excitation frequency."
Building on this framework, the researchers integrated the model with a mechanical architecture to construct a droplet-based pressure sensor. Systematic testing under varied ionic conductivities and excitation frequencies demonstrated that sensitivity can be enhanced by as much as 8772% solely through electrical parameter tuning, without any modification to device structure.
"This finding highlights a previously underappreciated design dimension," Jin Ge noted. "Whereas most existing studies focus on materials innovation and structural optimization, our results show that precise regulation of electrical parameters can serve as an equally effective route to performance enhancement."
To assess the generality of the strategy, the team extended the system from liquid droplets to solid-state ionic conductors by replacing the droplet with a hydrogel. The same performance trends were observed, confirming that the proposed mechanism and optimization approach are broadly applicable across different iontronic material systems.
The researchers further demonstrated practical applications of both device formats. The droplet-based sensor was integrated into a robotic arm for real-time contact pressure monitoring and discrimination of objects with varying softness. Meanwhile, a 4 × 4 pressure-sensing array based on the hydrogel device enabled spatially resolved pressure mapping, highlighting its potential for tactile imaging.
By identifying ionic conductivity and excitation frequency as key governing parameters and establishing a quantitative framework for their modulation, this work advances the fundamental understanding of iontronic sensing mechanisms. "We anticipate that this strategy will complement existing materials and structural approaches, opening new avenues for the rational design and optimization of high-performance iontronic sensors," Jin Ge said.
Other contributors include Yongming Wang, Jiasen Xie, Mingwei Gu, Ying Yang, Xingyu Ma, Lin Zheng, Junshuai Chen, Yunjie Lu and Jinhui Gu from the MOE Laboratory of Bioinorganic and Synthetic Chemistry, GBRCE for Functional Molecular Engineering, LIFM, IGCME, School of Chemistry, Sun Yat-Sen University, Guangzhou, China.
This work was supported by the National Natural Science Foundation of China (22475242) and the Guangdong Basic and Applied Basic Research Foundation (2025A1515010271).
DOI Link:
https://doi.org/10.26599/NR.2026.94908691
About Nano Research
Nano Research is a peer-reviewed, open access, international and interdisciplinary research journal, sponsored by Tsinghua University and the Chinese Chemical Society, published by Tsinghua University Press on the platform SciOpen. It publishes original high-quality research and significant review articles on all aspects of nanoscience and nanotechnology, ranging from basic aspects of the science of nanoscale materials to practical applications of such materials. After 18 years of development, it has become one of the most influential academic journals in the nano field. Nano Research has published more than 1,000 papers every year from 2022, with its cumulative count surpassing 8,000 articles. In 2025 InCites Journal Citation Reports, its 2025 IF is 9.4 (8.3, 5 years), and it continues to be the Q1 area among the four subject classifications. Nano Research Award, established by Nano Research together with TUP and Springer Nature in 2013, and Nano Research Young Innovators (NR45) Awards, established by Nano Research in 2018, have become international academic awards with global influence.
