Sustainable and Biodegradable Wood Sponge Piezoelectric Nanogenerator for Sensing and Energy Harvesting Applications

Abstract

Developing low-cost and biodegradable piezoelectric nanogenerators is of great importance for a variety of applications, from harvesting low-grade mechanical energy to wearable sensors. Many of the most widely used piezoelectric materials, including lead zirconate titanate (PZT), suffer from serious drawbacks such as complicated synthesis, poor mechanical properties (e.g. brittleness) and toxic composition, limiting their development for biomedical applications and posing environmental problems for their disposal. Here, we report a lowcost, biodegradable, biocompatible and highly compressible piezoelectric nanogenerator based on a wood sponge obtained with a simple delignification process. Thanks to the enhanced compressibility of the wood sponge, our wood nanogenerator (15 × 15 × 14 mm 3 , longitudinal × radial × tangential) can generate an output voltage of up to 0.69 V, 85 times higher than that generated by native (untreated) wood, and it shows stable performance under repeated cyclic compression (≥600 cycles). Our approach suggests the importance of increased compressibility of bulk materials for improving their piezoelectric output. We demonstrate the versatility of our nanogenerator by showing its application both as a wearable movement monitoring system (made with a single wood sponge) and as a large-scale prototype with increased output (made with 30 wood sponges) able to power simple electronic devices (a LED light, a LCD screen). Moreover, we demonstrate the biodegradability of our wood sponge piezoelectric nanogenerator by studying its decomposition with cellulosedegrading fungi. Our results showcase the potential application of wood sponge as a sustainable energy source, as a wearable device for monitoring human motions, and its contribution to environmental sustainability by electronic waste reduction.

Enhanced mechanical energy conversion with selectively decayed wood

“…The curve obtained with a loading of 100 kPa shows a much higher energy dissipation than the other two curves, indicating that there is a stress limit for repeating loading events, which is around 45 to 50 kPa for these samples. In previous research, chemical approaches involving, e.g., sodium chlorite, sodium hydroxide, or acetic acid/hydrogen peroxide, have been used to remove lignin and hemicellulose from wood (29,38). Such methods are faster and more efficient than the use of white rot fungi and could result in more compressible wood structures.…”

Self‐Polarized ZrO2/Poly(vinylidene fluoride‐co‐hexafluoropropylene) Nanocomposite‐Based Piezoelectric Nanogenerator and Single‐Electrode Triboelectric Nanogenerator for Sustainable Energy Harvesting from Human Movements

“…The maximum instantaneous power density obtained by fabricated PENG is larger than the previously reported PVDF/AlO‐rGO composite PENG by Karan et al and many others and the comparative tabulated forms are shown in Supporting Information T1. [ 55–60 ] Frequency‐dependent output voltage performance is also observed from 1 to 6 Hz of the fabricated PENGs by finger imparting (imparting force ≈28 N), as shown in Figure 5f. Maximum output voltage has been obtained at 6 Hz frequency.…”

Fabrication and application of biocompatible nanogenerators

“…OPEN ACCESS Niu et al, 2020;Najjar et al, 2017;Saravanakumar et al, 2015;Sun et al, 2020a;Sun et al, 2020b;Wang et al, 2017). In addition to serving as a power source, biocompatible nanogenerators can also be used as a sensor, such as a pressure sensor or chemical sensor (Khandelwal et al, 2019;Kim et al, 2018b;Qian et al, 2019;Saravanakumar et al, 2015 (Saravanakumar et al, 2015).…”

“…Figure9. Biocompatible nanogenerators for energy harvesting (A and B) (A) A diagram of wood sponge-based PENG and (B) its application in a self-powered system(Sun et al, 2020a). (C-E) Flexible and transparent TENGs served as body movement sensors, which clearly distinguished motions of a foot, ankle, knee, wrist, and neck(Kim et al, 2018b).…”