LEGO-block-inspired versatile triboelectric nanogenerators as power cells to harvest vibration energy

Triboelectric nanogenerators (TENGs) are efficient low-frequency and high-entropy mechanical energy harvesting devices that can provide sustainable power supply for Internet of Things applications. However, TENGs have low versatility and practicability because they need to be optimized for every application scenario. Inspired by LEGO blocks, we developed small-size, high-energy-density multifunctional triboelectric nanogenerators (LI-TENGs). Similar to a power cell, LI-TENGs are compact, can be rapidly assembled and connected, do not require additional wires for connecting devices, have high space utilization, and exhibit considerable capability for various low-frequency vibration mechanical energy harvesting applications. With an arched spring-steel sheet laminating structure, a tiny LI-TENG can transfer charge up to 760 nC and reach an open-circuit voltage of 210 V, an output charge volume density of up to 7 mC m(-3) under mechanical vibrations at low frequencies (<5 Hz), and a volume power density of 48.47 W m(-3) at a load resistance of 2.72 M omega. LI-TENG units can be assembled into a parallel or perpendicular configuration for harvesting multi-directional vibration energies. Moreover, the LI-TENG has been successfully applied to various practical scenarios, such as vehicle night warning and blue energy harvesting. Thus, LI-TENGs provide a novel design approach for obtaining versatile TENGs and their arrays.