Battling electricity scarcity with Li – TENGs

Fig1. Working representation of a TENG.

Triboelectric nanogenerators (TENGs) have the potential to drive the future of electricity generation and nanotechnology. We already see studies aiming TENGs with innovation strategies like surface microstructure treatment, multilayer design and additive pump design in place, to maximize the current output. The study in focus involves Li-TENGs (Lever-inspired contact separation TENGs), which can increase the charge transfer speed considerably. By increasing the magnification from 22 to 50 times, one can increase the voltage of Li-TENG from 91 V to 232 V.

Novelty of Li – TENG

Increasing energy scarcity demands out of the box thinking from our end. Since their inception in 2012, TENGs have exhibited promising results in wide range of applications like self-powered sensors and mechanical energy harvesting. Contact separation working mode TENG is now considered as the fundamental mode, due to its ability to generate high output power instantaneously and its relatively simpler design and preparation when compared to its counterparts like lateral sliding mode, freestanding triboelectric-layer mode and single-electrode mode.

We already have a couple of major innovations in place with regards to contact – separation TENGs. Multilayer designs have been proposed to increase the area of storing charge and a pump is introduced into the TENG to counter the limitation of maximum surface charge density. Above mentioned strategies are helpful in increasing the surface charge of the TENG, but the study in discussion aim over increasing the transfer speed of the electric charge.

Varying the lever ratio in order to change the contact separation velocity can significantly increase the signal output without making change to the charge transfer amount. Increasing the magnification from 22 to 50 times, improved the maximum power from 83 to 1031 µW. For example, a self powered pulse sensor with this application measured a pulse signal of 12.3 V, which is considerably larger value to its counterparts.

Fabrication and setup of Li – TENG

The main bar of the design is produced by 3D printing a stereolithography material and the rest are manufactured using laser cutting acrylic. Acrylic glue is used to fuse the main bar and its holder. Silver electrode was sputtered on the Polyimide film with the help of magnetron sputtering and on the other end fluorinated ethylene propylene film with and adhesive is glued. The curved upper layer is obtained with the help of pre compressed PI-Ag-FEP with the help of a double sided adhesive.

To measure the voltage generated by the Li – TENG a mixed domain oscilloscope and a high voltage differential probe is employed. The movement of the upper frictional layer is controlled with the help of a linear motor.

Finite element analysis is also employed to simulate the behavior of Li – TENG. Using ABAQUS, the bending of the main bar and the uniaxial compression behavior of the upper friction layer are observed.

The lever of the main bar can amplify the velocity of current by a factor of l1/l0. Where l0 is the distance of the bar from its front end to its fulcrum point, while l1 is the distance from the other end. The top end of the setup is curved to make sure that the contact at the region of interest is more than a line for a particular range of angular deflection.

Measurements and performance

It is observed that the magnitude of the voltage is directly proportional to the contact separation speed employed with the help of a linear motor. The relative positions of the lower and higher friction layers also influenced the output voltage of the setup. For example, when the position of the lower frictional layer rises, slight decrease in the voltage is observed. Another obvious result noted is the considerable increase in the output voltage with the increase of the magnification.

Based on the observed results, design and selection of the screw in the apparatus can also influence the noted parameters. This inference might come in handy, when analyzing real life applications and designs.


Proposed innovation of Li – TENG has certainly exhibited promising results, encouraging additional focus and experimentation from fellow researchers. Pioneering the highest output voltage capacity when compared to its counterparts, expecting research and advancements in in the field of Li – TENGs is only logical and hopefully effective practical applications in future is not at all an exaggeration.


  1. For more information please refer: Lever-inspired triboelectric nanogenerator with ultra-high output for
    pulse monitoring, Maoyi Zhang, Wenxuan Zhu, Tongtong Zhang, Yewang Su, Ya Yang

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