Charge-Boosting Strategy for Wearable Nanogenerators Enabled by Integrated Piezoelectric/Conductive Nanofibers

Abstract

The surface charge density enhancement by incorporating conductive paths into organic/inorganic piezoelectric composites is considered to be an effective way to achieve high-performance piezoelectric nanogenerators (PENGs). However, it is challenging to boost the charge density of aligned piezoelectric nanofibers due to the difficulty in efficiently building well-distributed conductive paths in their dense structure. In this work, a charge boosting strategy was proposed for enhancing the surface charge density of aligned piezoelectric nanofibers, that is, synchronously preparing piezoelectric/conductive hybrid nanofibers to realize the effective conductive paths for transferring the underlying charges to the surface of the PDMS/BaTiO3 composites. To this end, antimony-doped tin oxide (ATO) conductive nanofibers and barium titanate (BaTiO3) piezoelectric nanofibers with the same preparation conditions were selected and synchronously prepared by the polymer template electrospinning technology, followed by the calcination process. Benefiting from the well-distributed conductive paths for transferring the charges, the open-circuit voltage and short-circuit current of a PENG with 12 wt% ATO in hybrid nanofibers reached 46 V and 14.5 μA (30 kPa pressure), respectively, which were much higher than the pristine BaTiO3-based PENG. The high piezoelectric performance of the developed PENGs guaranteed their great potential applications in powering wearable microelectronics and monitoring human activity. This charge boosting strategy via the piezoelectric/conductive hybrid nanofibers may inspire the further development of high-performance energy harvesting technology.

Robust multi‐walled carbon nanotubes@thermoplastic polyurethane porous films with conductive fabrics for wearable triboelectric nanogenerators

“…This is because MWCNT fillers dispersed in porous membranes can form multiple microcapacitors, the number of which increases with increasing MWCNT filler content. The distance between MWCNT fillers decreases with increasing MWCNT content, resulting in an increasing in the average capacitance of microcapacitors, leading to an increase in the dielectric constant of MWCNT‐doped porous membranes 26,27 . The dielectric loss of the MWCNT@TPU films increased with the increment of MWCNT contents, which is because of the increased current leakage caused by the high electrical conductivity of MWCNT fillers 26 …”

“…The distance between MWCNT fillers decreases with increasing MWCNT content, resulting in an increasing in the average capacitance of microcapacitors, leading to an increase in the dielectric constant of MWCNT-doped porous membranes. 26,27 The dielectric loss of the MWCNT@TPU films increased with the increment of MWCNT contents, which is because of the increased current leakage caused by the high electrical conductivity of MWCNT fillers. 26 The triboelectric performance of TENGs based on porous MWCNT@TPU films were tested and shown in Figure 3C,D.…”

“…26,27 The dielectric loss of the MWCNT@TPU films increased with the increment of MWCNT contents, which is because of the increased current leakage caused by the high electrical conductivity of MWCNT fillers. 26 The triboelectric performance of TENGs based on porous MWCNT@TPU films were tested and shown in Figure 3C,D. As can be seen, the performance of TENG showed an increasing trend with the increase of MWCNT content.…”

Electrospun Micro/Nanofiber-Based Biomechanical Sensors

“…Also, this method allows processing management at every stage of preparation, ultimately contributing to the superior piezoelectric performance of electrospun micro/nanofibers. In short, the electrospinning technique provides a solution for the development of efficient piezoelectric polymer membranes. − Extensive efforts have been dedicated to improving the piezoelectric effect of electrospun polymer micro/nanofibers, leading to a remarkable progress in this recently . For instance, Gu et al fabricated a PU/poly-L-lactic acid (PLLA) nanofibrous membrane by electrospinning which is subsequently utilized to develop a piezoelectric sensor.…”

Development of Piezoelectric Elastomers and Their Applications in Soft Devices

“…The PENG was also highly flexible and durable, with no significant observed fluctuations in piezoelectric output of even after bending the device at angles 2000 times. Similarly, Yan [120] et al introduced conductive paths in piezoelectric composites to enhance their piezoelectric performance. They added ATO nanofibers as conductive paths into the PENG of BT/PDMS, resulting in a significant improvement in piezoelectric output.…”