No. 13. Figure-of-Merits (FOM) for Direct Current TENG (Triboelectric Nanogenerator): Structural vs Dimensionless Manuscript Received: 23 June 2023, Accepted: 23 July 2023, Published: 15 September 2023, ORCiD: 0009-0000-9884-7207

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Mohamed Omer Mahgoub Abdelrahim
Lini Lee
Yew Keong Sin


This review paper provides a detailed overview of figure-of-merits (FOM) of Direct Current triboelectric nanogenerators (DC-TENGs). TENG represent a potentially ground-breaking technology for extracting mechanical energy from the environment. The FOM is a critical parameter that determines the efficiency of the energy conversion. This paper discusses the various working modes of DC-TENGs and also the research done to maximize output charge density. The review looks at recent different FOMs that could be formulated to improve the analysis of the performance and efficiency of TENGs more accurately. Finally, the paper concludes with a comparison between two different types of FOMs namely structural FOMs and dimensionless FOMs. It provides a valuable resource for researchers working in the field of TENGs and it sheds light on the key factors that influence the FOM of DC-TENGs. This enables the development of more efficient energy harvesting devices.

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J. Peng, S. D. Kang and G. J. Snyder, “Optimization Principles and the Figure of Merit for Triboelectric Generators,” Sci. Adv., vol. 3, no. 12, pp. eaap8576, 2017.

Z. L. Wang and A. C. Wang, “On the Origin of Contact-electrification,” Mater. Today, vol. 30, pp. 34–51, 2019.

Q. T. Nguyen, C. P. Vo, T. H. Nguyen and K. K. Ahn, “A Direct-current Triboelectric Nanogenerator Energy Harvesting System Based on Water Electrification for Self-Powered Electronics,” Appl. Sci., vol. 12, no. 5, pp. 2724, 2022.

Z. L. Wang, “On Maxwell's Displacement Current for Energy And Sensors: The Origin of Nanogenerators,” Mater. Today, vol. 20, no. 2, pp. 74–82, 2017.

Z. L. Wang, T. Jiang and L. Xu, “Toward the Blue Energy Dream by Triboelectric Nanogenerator Networks,” Nano Energ., vol. 39, pp. 9–23, 2017.

C. Fang, T. Tong, T. Bu, Y. Cao, S. Xu, Y. Qi and C. Zhang, “Overview of Power Management for Triboelectric Nanogenerators,” Adv. Intell. Sys., vol. 2, no. 2, pp. 1900129, 2020.

S. Niu, S. Wang, L. Lin, Y. Liu, Y. S. Zhou, Y. Hu and Z. L. Wang, “Theoretical Study of Contact-Mode Triboelectric Nanogenerators As An Effective Power Source,” Energ. Environ. Sci., vol. 6, no. 12, pp. 3576, 2013.

X. Pu, S. An, Q. Tang, H. Guo and C. Hu, “Wearable Triboelectric Sensors for Biomedical Monitoring and Human-machine Interface,” iSci., vol. 24, no. 1, pp. 102027, 2021.

Z. Zhao, Y. Dai, D. Liu, L. Zhou, S. Li, Z. L. Wang and J. Wang, “Rationally Patterned Electrode of Direct-Current Triboelectric Nanogenerators for Ultrahigh Effective Surface Charge Density,” Nat. Commun., vol. 11, no. 6186, 2020.

Z. L. Wang, “Triboelectric Nanogenerators As New Energy Technology for Self-Powered Systems and As Active Mechanical and Chemical Sensors,” ACS Nano, vol. 7, no. 11, pp. 9533–9557, 2013.

M. O. Abdelrahim and L. Lee, “Design of DC-triboelectric Nanogenerator for Energy Harvesting,” Int. J. Technol., vol. 13, no. 6, pp. 1308-1316, 2022.

S. Niu, Y. Liu, S. Wang, L. Lin, Y. S. Zhou, Y. Hu, and Z. L. Wang, “Theory of Sliding-mode Triboelectric Nanogenerators,” Adv. Mater., vol. 25, no. 43, pp. 6184–6193, 2013.

D. Liu, X. Yin, H. Guo, L. Zhou, X. Li, C. Zhang, J. Wang and Z. L. Wang, “A Constant Current Triboelectric Nanogenerator Arising from Electrostatic Breakdown,” Sci. Adv., vol. 5, no. 4, pp. eaav6437, 2019.

L. Zhou, D. Liu, S. Li, Z. Zhao, C. Zhang, X. Yin, L. Liu, S. Cui, Z. L. Wang, and J. Wang, “Rationally Designed Dual - mode Triboelectric Nanogenerator for Harvesting Mechanical Energy By Both Electrostatic Induction and Dielectric Breakdown Effects,” Adv. Energ. Mater., vol. 10, no. 24, pp. 2000965, 2020.

J. Wang, C. Wu, Y. Dai, Z. Zhao, A. Wang, T. Zhang and Z. L. Wang, “Achieving Ultrahigh Triboelectric Charge Density for Efficient Energy Harvesting,” Nat. Commun., vol. 8, no. 88, 2017.

J. Wang, S. Li, F. Yi, Y. Zi, J. Lin, X. Wang, Y. Xu and Z. Lin Wang, “Sustainably Powering Wearable Electronics Solely By Biomechanical Energy,” Nat. Commun., vol. 7, no. 12744, 2016.

C. Zhang, L. Zhou, P. Cheng, Y. G. Xing, D. Liu, Xinyuan, L. H. Guo, Z. L. Wang and J. Wang, “Surface Charge Density of Triboelectric Nanogenerators: Theoretical Boundary and Optimization Methodology,” Appl. Mater. Today, vol. 18, pp. 100496, 2020.

L. Cheng, Q. Xu, Y. Zheng, X. Jia and Y. Qin, “A self-improving Triboelectric Nanogenerator with Improved Charge Density and Increased Charge Accumulation Speed,” Nat. Commun., vol. 9, no. 3773, 2018.

L. Xu, T. Z. Bu, X. D. Yang, C. Zhang and Z. L. Wang, “Ultrahigh Charge Density Realized By Charge Pumping At Ambient Conditions for Triboelectric Nanogenerators,” Nano Energ., vol. 49, pp. 625–633, 2018.

W. Liu, Z. Wang, G. Wang, G. Liu, J. Chen, X. Pu, Y. Xi, X. Wang, H. Guo, C. Hu and Z. L. Wang, “Integrated Charge Excitation Triboelectric Nanogenerator,” Nat. Comm., vol. 10, no. 1426, 2019.

Y. Liu, W. Liu, Z. Wang, W. He, Q. Tang, Y. Xi, X. Wang, H. Guo and C. Hu, “Quantifying Contact Status and The Air-Breakdown Model of Charge-Excitation Triboelectric Nanogenerators to Maximize Charge Density,” Nat. Comm., vol. 11, no. 1599, 2020.

D. Liu, L. L. Zhou, S. X. Li, Z. H. Zhao, X. Yin, Z. Y. Yi, C. L. Zhang, X. Y. Li, J. Wang and Z. L. Wang, “Hugely Enhanced Output Power of Direct-Current Triboelectric Nanogenerators By Using Electrostatic Breakdown Effect,” Adv. Mater. Technol., vol. 5, no. 7, pp. 2000289, 2020.

S. Wang, Y. Xie, S. Niu, L. Lin, C. Liu, Y. S. Zhou and Z. L. Wang, “Maximum Surface Charge Density for Triboelectric Nanogenerators Achieved By Ionized-Air Injection: Methodology and Theoretical Understanding,” Adv. Mater., vol. 26, no. 39, pp. 6720–6728, 2014.

Z. Wang, L. Cheng, Y. Zheng, Y. Qin and Z. L. Wang, “Enhancing the Performance of Triboelectric Nanogenerator Through Prior-Charge Injection and Its Application on Self-Powered Anticorrosion,” Nano Energ., vol. 10, pp. 37–43, 2014.

J. Chun, B. U. Ye, J. W. Lee, D. Choi, C.-Y. Kang, S.-W. Kim, Z. L. Wang and J. M. Baik, “Boosted Output Performance of Triboelectric Nanogenerator via Electric Double Layer Effect,” Nat. Commun., vol. 7, no. 12985, 2016.

J. Chun, J. W. Kim, W. S. Jung, C. Y. Kang, S. W. Kim, Z. L. Wang and J. M. Baik, “Mesoporous Pores Impregnated with Au Nanoparticles As Effective Dielectrics for Enhancing Triboelectric Nanogenerator Performance in Harsh Environments,” Energ. Environ. Sci., vol. 8, no. 10, pp. 3006–3012, 2015.

T. H. Fay and S. D. Graham, “Coupled Spring Equations,” Int. J. Math. Edu. in Sci. and Technol., vol. 34, no. 1, pp. 65–79, 2003.

G. Zhu, Z. H. Lin, Q. Jing, P. Bai, C. Pan, Y. Yang, Y. Zhou and Z. L. Wang, “Toward Large-scale Energy Harvesting By A Nanoparticle-Enhanced Triboelectric Nanogenerator,” Nano Lett., vol. 13, no. 2, pp. 847–853, 2013.

H. Wang, L. Xu, Y. Bai, and Z. L. Wang, “Pumping Up the Charge Density of A Triboelectric Nanogenerator By Charge-Shuttling,” Nat. Commun., vol. 11, no. 4230, 2020.

H. Wu, S.Fu, W. He, C. Shan, J. Wang, Y. Du, S. Du and B. Li, “Improving and Quantifying Surface Charge Density via Charge Injection Enabled By Air Breakdown,” Adv. Funct. Mater., vol. 32, no. 35, pp. 2203884, 2022.

Z. L. Wang, J. Chen and L. Lin, “Progress in Triboelectric Nanogenerators As A New Energy Technology and Self-Powered Sensors,” Energ. Environ. Sci., vol. 8, no. 8, pp. 2250–2282, 2015.

S. Niu and Z. L. Wang, “Theoretical Systems of Triboelectric Nanogenerators,” Nano Energ., vol. 14, pp. 161–192, 2015.

J. Luo, L. Xu, W. Tang, T. Jiang, F. R. Fan, Y. Pang, L. Chen, Y. Zhang and Z. L. Wang, “Direct-current Triboelectric Nanogenerator Realized By Air Breakdown Induced Ionized Air Channel,”Adv. Energ. Mater., vol. 8, no. 27, pp. 1800889, 2018.

Y. Zi, S. Niu, J. Wang, Z. Wen, W. Tang and Z. L. Wang, “Standards and Figure-of-Merits for Quantifying the Performance of Triboelectric Nanogenerators,” Nat. Commun., vol. 6, no. 8376, 2015.

G. Cheng, Z. H. Lin, L. Lin, Z. Du and Z. L. Wang, “Pulsed Nanogenerator with Huge Instantaneous Output Power Density,” ACS Nano, vol. 7, no. 8, pp. 7383–7391, 2013.

S. Niu, Y. Liu, S. Wang, L. Lin, Y. S. Zhou, Y. Hu and Z. L. Wang, “Theoretical Investigation and Structural Optimization of Single-Electrode Triboelectric Nanogenerators,” Adv. Funct. Mater., vol. 24, no. 22, pp. 3332–3340, 2014.

H. T. Baytekin, A. Z. Patashinski, M. Branicki, B. Baytekin, S. Soh and B. A. Grzybowski, “The Mosaic of Surface Charge in Contact Electrification,” Sci., vol. 333, no. 6040, pp. 308–312, 2011.

T. A. L. Burgo, T. R. D. Ducati, K. R. Francisco, K. J. Clinckspoor, F. Galembeck and S. E. Galembeck, “Triboelectricity: Macroscopic Charge Patterns Formed By Self-Arraying Ions on Polymer Surfaces,” Langmuir, vol. 28, no. 19, pp. 7407–7416, 2012.

W. Tang, T. Jiang, F. R. Fan and A. F. Yu, “Liquid-metal Electrode for High-Performance Triboelectric Nanogenerator At An Instantaneous Energy Conversion Efficiency of 70.6%,” Adv. Funct. Mater., vol. 25, no. 24, pp. 3718–3725, 2015.