Biowaste-Derived Triboelectric Nanogenerators for Emerging Bioelectronics

Abstract

Triboelectric nanogenerators (TENGs) combine contact electrification and electrostatic induction effects to convert waste mechanical energy into electrical energy. As conventional devices contribute to electronic waste, TENGs based on ecofriendly and biocompatible materials have been developed for various energy applications. Owing to the abundance, accessibility, low cost, and biodegradability of biowaste (BW), recycling these materials has gained considerable attention as a green approach for fabricating TENGs. This review provides a detailed overview of BW materials, processing techniques for BW-based TENGs (BW-TENGs), and potential applications of BW-TENGs in emerging bioelectronics. In particular, recent progress in material design, fabrication methods, and biomechanical and environmental energy-harvesting performance is discussed. This review is aimed at promoting the continued development of BW-TENGs and their adoption for sustainable energy-harvesting applications in the field of bioelectronics.

Keywords: biocompatibility; bioelectronics; biowaste; energy harvesting; triboelectric nanogenerator.

Figure 1

Schematic of BW materials used for TENG fabrication.

Figure 2

Schematics illustrating the fabrication of untreated BW‐TENGs using a) a piece of fallen deciduous leaf. Reproduced with permission.^{[ 22 ]} Copyright 2021, MDPI; b) rose petals;^{[ 23 ]} c) Delonix regia flower (DRF) powder adhered to an electrode. Reproduced with permission.^{[ 24 ]} Copyright 2022, Wiley‐VCH; d) Clitoria ternatea (CT) flower extract distributed in a PVA matrix. Reproduced with permission.^{[ 25 ]} Copyright 2023, Elsevier; and e) rabbit fur stuck a rotor in a rotary TENG. Reproduced with permission.^{[ 32 ]} Copyright 2023, IOP publishing.

Figure 3

Schematics of chemical refinement processes for preparing a) cellulose from wood waste. Reproduced with permission.^{[ 35 ]} Copyright 2023, American Chemical Society; b) gelatin from fish scale waste. Reproduced with permission.^{[ 35 ]} Copyright 2023, American Chemical Society; c) chitosan from crab shell waste. Reproduced with permission.^{[ 35 ]} Copyright 2023, American Chemical Society; and d) collagen from tanned leather shavings for TENG fabrication. Reproduced with permission.^{[ 46 ]} Copyright 2022, Royal Society of Chemistry.

Figure 4

a) High‐temperature sintering for the carbonization of an electrospun lignin fiber mat for TENG fabrication. Reproduced with permission.^{[ 60 ]} Copyright 2022, Wiley‐VCH. b) Hydrothermal treatment of discarded paddy straw to prepare graphene quantum dots for composite TENG fabrication. Reproduced with permission.^{[ 62 ]} Copyright 2023, American Chemical Society. c) LIG of PI and paper to fabricate a TENG with built‐in electrodes. Reproduced with permission.^{[ 72 ]} Copyright 2020, Elsevier.

Figure 5

Working mechanism of TENGs depicted using an electron cloud–potential well model.^{[ 77 ]}

Figure 6

a) Chemical structures of the constituents of lignocellulosic biomass. Reproduced with permission.^{[ 83 ]} Copyright 2018, Wiley‐VCH. b) FTIR spectra and c) triboelectric voltage generated by various bagasse materials. Reproduced with permission.^{[ 77 ]} Copyright 2022, Wiley‐VCH. d) FTIR spectra and e) triboelectric voltage generated by dry fruit shells. Reproduced with permission.^{[ 29 ]} Copyright 2022, Elsevier. f) Chemical structures of chitin and chitosan. Reproduced with permission.^{[ 94 ]} Copyright 2015, MDPI. g) FTIR spectra and h) triboelectric voltages generated by prawn‐shell‐derived chitosan. Reproduced with permission.^{[ 96 ]} Copyright 2022, Springer Nature.

Figure 7

a) Chemical structures of keratin, b) FTIR spectra of keratin‐enriched snake ecdysis and deconvoluted analysis in the regions of c) 3000–3600 and d) 1180—1300 cm⁻¹, and e) triboelectric voltages generated snake‐ecdysis‐based TENGs incorporating various materials. Reproduced with permission.^{[ 103 ]} Copyright 2023, Elsevier. f) Chemical structures of the constituents of collagen, and g) FTIR spectra and h) TENG performance of collagen‐enriched chicken skin. Reproduced with permission.^{[ 108 ]} Copyright 2023, Springer Nature.

Figure 8

Structures and performance characteristic of cellulose‐based BW‐TENGs: a) leaf‐powder‐based TENG. Reproduced with permission.^{[ 112 ]} Copyright 2019, Elsevier; b) electrospun tree‐root bark‐based TENG. Reproduced with permission.^{[ 115 ]} Copyright 2022, Elsevier; c) sunflower‐husk‐based TENG. Reproduced with permission.^{[ 118 ]} Copyright 2021, Elsevier; d) corn‐bran‐based rotary TENG. Reproduced with permission.^{[ 120 ]} Copyright 2022, Elsevier; e) wheat‐straw‐based TENGs with windmill‐ and lawn‐like designs. Reproduced with permission.^{[ 122 ]} Copyright 2021, Elsevier; and f) wastepaper‐based TENG in CS, FS, and SE modes. Reproduced with permission.^{[ 17 ]} Copyright 2023, Wiley‐VCH.

Figure 9

Structures and performance characteristics of collagen‐ and gelatin‐based BW‐TENGs: a) shrimp‐shell‐derived chitosan‐based TENG. Reproduced with permission.^{[ 96 ]} Copyright 2022, Springer Nature; b) fish‐bladder film‐based TENG. Reproduced with permission.^{[ 137 ]} Copyright 2020, American Chemical Society; c) chicken‐skin‐based TENG. Reproduced with permission.^{[ 108 ]} Copyright 2023, Springer Nature; d) eggshell‐membrane‐based TENG. Reproduced with permission.^{[ 141 ]} Copyright 2023, American Chemical Society; e) fish‐scale‐derived gelatin‐based TENG. Reproduced with permission^{[ 144 ]} Copyright 2023, Elsevier; and f) human‐hair‐based TENG. Reproduced with permission.^{[ 146 ]} Copyright 2022, American Chemical Society.

Figure 10

Energy‐harvesting performance of biocompatible TENGs prepared using a) carbonized waste coffee grounds. Reproduced with permission.^{[ 147 ]} Copyright 2021, Elsevier; b) carbonized cotton cloth. Reproduced with permission.^{[ 149 ]} Copyright 2020, Royal Society of Chemistry; c) carbonized waste human hair. Reproduced with permission.^{[ 150 ]} Copyright 2022, MDPI; d) carbonized loofah. Reproduced with permission.^{[ 156 ]} Copyright 2023, Elsevier; e) carbonized plant fiber. Reproduced with permission.^{[ 157 ]} Copyright 2023, Elsevier; and f) carbonized plant‐derived cellulose. Reproduced with permission.^{[ 160 ]} Copyright 2021, Elsevier.

Figure 11

Comparison of the output voltages of untreated, treated, and carbonized BW‐TENGs: output voltages a) below 1 kV and b) above 1 kV.

Figure 12

Cellulose‐based TENG for tactile password recognition: a) four TENGs used to prepare the password input system; a positive signal was generated by each TENG when touched with a finger wearing nitrile rubber glove, b) V _oc generated by each TENG when touched 5 times with a finger wearing nitrile rubber glove, c) digital photograph of the password recognition switch system, d) program for setting the password, which was decrypted by touching the TENGs in the sequence “1234,” and e) detection of password recognition via lighting of an LED. Reproduced with permission.^{[ 162 ]} Copyright 2022, Elsevier. Smart‐home controller: f) schematic of the BW‐TENG‐based smart home controller switch, g) schematic of the entire device, h) voltages generated by the I) TENG and II) comparator, and III) signal transmitted to the relay by the microcontroller, and i) digital photographs of appliance control using the TENG. Reproduced with permission.^{[ 96 ]} Copyright 2022, Springer Nature.

Figure 13

a) Electrical output of five carbonized ground coffee (CG)‐based TENG sensors corresponding to finger gestures representing the numbers 0, 1, 2, 3, 4, and 5, and b) human hand gesture emulation by a robotic hand. Reproduced with permission.^{[ 147 ]} Copyright 2021, Elsevier. c) Illustration of a carbon‐coated paper‐wipe‐based TENG in the form of a wearable smart wrist band for Morse code generation in emergency situations, and d) letter and number generation by a 9‐segment self‐powered keyboard prepared using the carbon‐coated paper‐wipe‐based TENG. Reproduced with permission.^{[ 96 ]} Copyright 2022, Springer Nature.

Figure 14

a) BW‐derived flame‐retardant TENG adhered to a chair for sitting posture monitoring, and b) voltage signal generated by the TENG at different sitting postures represented by LED lightening. Reproduced with permission.^{[ 167 ]} Copyright 2022, American Chemical Society. c) Real‐time images of a BW‐TENG applied in self‐powered remote impact‐monitoring system, with d) its device schematics. Reproduced with permission.^{[ 60 ]} Copyright 2022, Wiley‐VCH. e) Fish‐bladder‐based TENG for proximity sensing, and f) response curves of the TENG corresponding to contact and noncontact motions at different starting points (0–27 mm). Reproduced with permission.^{[ 137 ]} Copyright 2020, American Chemical Society. g,h) Sports judgment analysis using TENG prepared from discarded fabric. Reproduced with permission.^{[ 178 ]} Copyright 2022, Elsevier. i) Schematic diagram of the self‐powered smart ward system using lignocellulosic TENG, j) schematic representation of the self‐powered smart ward, and k) operating interface of the self‐powered contactless medical monitoring system Reproduced with permission.^{[ 181 ]} Copyright 2023, Royal Society of Chemistry.

Figure 15

a) Real‐time oral health monitoring using crab shell derived chitosan based TENG refined food waste. Reproduced with permission.^{[ 35 ]} Copyright 2023, American Chemical Society. b) Real‐time respiration monitoring with TENG attached to abdomen of two patients. Reproduced with permission.^{[ 41 ]} Copyright 2022, Elsevier. c) Human motion monitoring via self‐powered strain sensing by carbonized loofah‐TENG sensor when attached on different parts of human body. Reproduced with permission.^{[ 156 ]} Copyright 2023, Elsevier. d) Photograph of the Cotton fabric‐TENG sensor after attaching inside a face mask and voltage response to breath for real‐time analysis. Reproduced with permission.^{[ 187 ]} Copyright 2023, Springer Nature.

Figure 16

Humidity‐sensing properties of TENGs fabricated using a) Clitoria ternatea flower powder. Reproduced with permission.^{[ 25 ]} Copyright 2023, Elsevier. b) Sunflower husk. Reproduced with permission.^{[ 118 ]} Copyright 2021, Elsevier. c) Dry fruit shells. Reproduced with permission.^{[ 29 ]} Copyright 2022, Elsevier. d) Leek skin. Reproduced with permission.^{[ 18 ]} Copyright 2022, Elsevier. e) Ulva lactuca. Reproduced with permission.^{[ 114 ]} Copyright 2024, Elsevier. f) Citrus peel pectin. Reproduced with permission.^{[ 192 ]} Copyright 2022, Royal Society of Chemistry.

Figure 17

a) TENG‐based photo‐sensing lab set up under illumination of different wavelengths. Photo‐sensing properties of TENGs fabricated using b,c) human hair with different photosensitive materials. Reproduced with permission.^{[ 195} , ^{196 ]} Copyright 2022 and 2023, MDPI and Elsevier. d) Corn husk. Reproduced with permission.^{[ 19 ]} Copyright 2023, Springer Nature. e) Graphitized paddy straw. Reproduced with permission.^{[ 62 ]} Copyright 2023, American Chemical Society.

Figure 18

a) Schematic of corn husk‐TENG‐operated wireless agro‐sensing circuit system. b) Digital photo of each parts of the circuit system. c) Digital photo of 1.7 km wireless transmission of the sensing data. d) Charging curves of a 0.1 F supercapacitor charged by the TENG while driving the wireless agro‐sensing system. e) Photo of the sensing data shown on the host computer. Reproduced with permission.^{[ 120 ]} Copyright 2022, Elsevier. f) Schematic of the construction of a plant growth‐promoting system that generates space electric fields via plant protein‐based TENG. g) Percentage of weight gain (left) and elongation (right) in control (without electric field) and test (with electric field) groups after 48 h of growth. Whiskers indicate mean ± standard deviation for n = 24 bean seeds per group. Two‐sample t‐test; **** p < 0.0001. h) Typical photographs of beans with (test) and without (control) electric field application before and after 48 h of growth. i) Schematic of the TENG used as biodegradable mulch film to construct growth‐promoting system that generates space electric field for agriculture. Reproduced with permission.^{[ 206 ]} Copyright 2022, Elsevier.

Figure 19

a) Schematic illustration of rabbit hair‐TENG‐operated self‐powered UV sterilization unit. b) Circuit diagram of the same. c) Photographs of Escherichia coli colonies sterilizing under the TENG powered UV irradiation for 0 min, 20 min, and 40 min. Reproduced with permission.^{[ 32 ]} Copyright 2023, IOP Publishing. d) Schematic illustration of the application scenario of the rabbit hair‐TENG powered curtain purification system for PM_2.5 removal and formaldehyde degradation. SEM self‐powered smog removal system powered by TENG. e) Comparison of the formaldehyde degradation effect (with and without the TENG). f) Comparison of the PM_2.5 removal at different rotation speed of the rotary TENG. Reproduced with permission.^{[ 207 ]} Copyright 2023, Royal Society of Chemistry.

Figure 20

Schematic of the challenges occurring in BW‐TENGs.