Solid-State Ion-Conductive Elastomers with Robustness and Conductivity for Pressure Sensors and Triboelectric Nanogenerators

Abstract

Solid-state ion-conductive elastomers (ICEs) serve as core materials for flexible electronic devices, demonstrating significant application potential in flexible pressure sensing, wearable electronics, and soft robotics. However, achieving a synergistic enhancement of mechanical properties and ionic conductivity in solid-state ion-conductive elastomers remains a substantial challenge. In this study, a multiple cross-linking strategy was employed. By incorporating lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) into a polyurethane matrix, a polyurethane-based solid-state ion-conductive elastomer (designated MCPU-100Li) exhibiting concurrent high mechanical strength and high ionic conductivity was designed and synthesized. Benefiting from the multiple cross-linked network within the polymer, MCPU-100Li demonstrates high tensile strength (6.56 MPa), high ionic conductivity (5.84 × 10–4 S cm–1), high tear resistance with a fracture energy of 17.4 kJ m–2 and good environmental stability. The flexible pressure sensor based on MCPU-100Li exhibits high sensitivity, rapid response, and robust stability, enabling precise detection of electrical signal variations under different pressures. Furthermore, integrated with a chessboard-like array, this sensor achieves high-resolution spatial mapping of position and pressure through multichannel signal analysis, demonstrating capabilities for diverse board layouts and dynamic recognition. Additionally, MCPU-100Li functions effectively as a key triboelectric layer material in triboelectric nanogenerators (TENGs), highlighting its promising potential for applications in wearable electronics and energy harvesting.