Fig. 13.

Electropinning yarn-based wearable nanogenerator, supercapacitor, and electrochemical actuator. (A) Schematic illustration of the working principles of a NY-based triboelectric nanogenerator. (B) Fabrication and applications of a strong electrochemical actuator. (a) Schematic of the fabrication process; (b) SEM image of the CNT yarn; (c) SEM image of electrospun PVDF-HFP nanofiber-coated CNT coverspun yarn; (d) SEM image of a twisted coverspun yarn; (e) SEM image of a self-plied yarn using two twisted coverspun yarns; (g) Photograph of an obtained yarn muscle wrapped on a mandrel; (h) A dumbbell was lifted by the yarn muscle when a 4 V voltage was applied; (i) The grasping and releasing of a object with the weight of 56 mg by yarn-made grippers when a 4 V voltage was periodly applied. (A) Reprinted with permission from Ref. [207]. (B) Reprinted with permission from Ref. [208].