A durable non-contact reciprocated triboelectric nanogenerator for low-frequency vibration energy harvesting

Harvesting vibration energy using a triboelectric nanogenerator (TENG) is a promising approach in solving the power supply restriction of the Internet of Things. Currently, the low durability due to friction surface wearing is the primary limitation of TENGs, which restricts their applicability and practicability. This study introduces a non-contact-type TENG aimed at significantly enhancing its durability by increasing its anti-wear capability. The configuration of the proposed TENG includes permanent magnets and rolling-balls. The reciprocating motion of functional friction surfaces, facilitated by the permanent magnets, enhances the efficiency of harvesting low-frequency vibration energy. The embedded rolling-balls are utilized to separate two functional friction surfaces, which minimizes the friction surface wearing between different dielectric materials. The electrical output characteristics of this non-contact TENG under variable load resistances are explored according to sinusoidal excitation based on either variable frequencies or accelerations. The results demonstrate that the proposed nanogenerator can generate a short-circuit current of 2118.2 nA and achieve a peak power density of 9.891 mW/m2. The electrical responses of this non-contact TENG remain stable over 120 000 continuous working cycles, lasting for more than 200 min. Furthermore, the nanogenerator can identify and harvest energy from running or jumping motions performed by individuals in different postures and at various speeds or heights. With its exceptional durability and stability, this non-contact nanogenerator offers a novel approach to low-frequency vibration energy harvesting, paving the way for practical applications in the field.