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Multifunctional metamaterials (MFMs) capable of energy harvesting and vibration control are particularly attractive for smart structures, wearable/biointegrated electronics, and intelligent robotics. Here, a novel MFM based on triboelectric nanogenerators (TENGs), which can harvest environmental energy and reduce vibration simultaneously, is reported. The unit cells of the MFM consist of a local resonator, an integrated contact‐ separation mode TENG, and spiral‐shaped connecting beams. A multiphysics theoretical model is developed for quantitatively evaluating the performance of the MFM by including the mechanical and electrical fields interactions, which is further validated by experimental testing. It is demonstrated that the TENG‐based MFM can not only effectively harvest vibration energy to power electronics but also dramatically suppress low‐frequency mechanical vibration. This work provides a new design and model for developing novel TENG‐based MFMs for advanced smart systems used in a variety of applications. [ABSTRACT FROM AUTHOR]

A novel tribotronic transistor has been developed by vertically coupling a single-electrode mode triboelectric nanogenerator and a MoS2 field effect transistor. Once an external material contacts with or separates from the device, negative charges are induced by triboelectrification on the surface of the polymer frictional layer, which act as a 'gate' voltage to modulate the carrier transport in the MoS2 channel instead of the conventional applied gate voltage; the drain-source current can be tuned in the range of 1.56-15.74 μA, for nearly ten times. The application of this MoS2 tribotronic transistor for the active smart tactile switch is also demonstrated, in which the on/off ratio can reach as high as ≈16 when a finger touches the device and the increased drain-source current is sufficient to light two light-emitting diodes. This work may provide a technique route to utilize the 2D materials based tribotronic transistors in MEMS, nanorobotics, and human-machine interfacing. [ABSTRACT FROM AUTHOR]

Additive manufacturing, i.e., 3D printing, is being increasingly utilized to fabricate a variety of complex‐shaped electronics and energy devices (e.g., batteries, supercapacitors, and solar cells) due to its excellent process flexibility, good geometry controllability, as well as cost and material waste reduction. In this review, the recent advances in 3D printing of emerging batteries are emphasized and discussed. The recent progress in fabricating 3D‐printed batteries through the major 3D‐printing methods, including lithography‐based 3D printing, template‐assisted electrodeposition‐based 3D printing, inkjet printing, direct ink writing, fused deposition modeling, and aerosol jet printing, are first summarized. Then, the significant achievements made in the development and printing of battery electrodes and electrolytes are highlighted. Finally, major challenges are discussed and potential research frontiers in developing 3D‐printed batteries are proposed. It is expected that with the continuous development of printing techniques and materials, 3D‐printed batteries with long‐term durability, favorable safety as well as high energy and power density will eventually be widely used in many fields. [ABSTRACT FROM AUTHOR]