Multimodal, Ultrasensitive, and Biomimetic Electronic Skin Based on Gradient Micro‐Frustum Ionogel for Imaginary Keyboard and Haptic Cognition

Abstract Electronic skins (E‐skins) are poised to revolutionize human interaction not only with one another but also with machines, electronics, and surrounding environment. However, the wearable E‐skin that simultaneously offers multiple sensing capabilities, high sensitivity, and broad sensing ranges remains a great challenge. Here, drawing inspiration from human haptic perception, a multimodal, ultrasensitive, and biomimetic E‐skin (MES) founded on micro‐frustum ionogel is developed based on iontronic capacitive and triboelectric effects for imaginary keyboard and multifunctional haptic cognition. Leveraging simultaneously the ionogel as capacitive layer and triboelectric layer, the MES enables human‐dermis perception performances of high sensitivity (357.56 kPa⁻¹), low limit of detection (0.47 Pa), and broad linear detection range (0–500 kPa). Moreover, human finger joint movements can be precisely monitored by the attached MES and be transferred into accurate typed letter information on an imaginary keyboard. More importantly, by harnessing signal acquisition/processing circuits and machine learning, the real‐time haptic cognition of different materials, surface roughness, and contact pressure can be achieved by the MES, which endows the advancement of interaction between next‐generation intelligent robot and physical environment. Consequently, the proposed MES demonstrates impressive potentials in the fields of wearable electronics, human–machine interaction (HMI), and Artificial Intelligence (AI).