Mechanically Robust and Highly Conductive Ionogels for Soft Ionotronics

Ionogels are promising materials for flexible electronics due to their continuous conductive phase, high thermal and chemical stability. However, a large amount of ionic liquid is required to get high conductivity, resulting in a sharp decline in the mechanical properties. Therefore, it is a great challenge to prepare ionogels with both high conductivity and mechanical properties, which is important for their practical applications. Herein, ionogels with high mechanical strength and stretchability, extraordinary ionic conductivity, excellent transparency, outstanding durability, and stability are fabricated with crosslinked polymer, ionic liquid, and lithium salt. The adoption of lithium salt can significantly improve both the mechanical strength and stretchability, which is a common dilemma in material science, and simultaneously, address the conflict between mechanical strength and ionic conductivity in ionogels. It is primarily corresponding to the microphase-separation effects induced by the lithium bonds formed between lithium ions and carbonyl groups on the polymer networks. Ionotronics including resistance-type sensors for strain and temperature sensing and triboelectric nanogenerators with stable output performance are fabricated. Moreover, ionogel-based microcircuit and sensing arrays with high resolution and accuracy are fabricated through digital light processing printing technology. The ionogels have great promise for various ionotronics in many fields.