Enhanced Output Performance of a Flexible Piezoelectric Nanogenerator Realized by Lithium-Doped Zinc Oxide Nanowires Decorated on MXene

Abstract

A flexible piezoelectric composite is composed of a polymer matrix and piezoelectric ceramic fillers to achieve good mechanical flexibility and processability. The overall piezoelectric performance of a composite is largely determined by the piezoelectric filler inside. Thus, different dispersion methods and additives that can promote the dispersion of piezoelectric ceramics and optimal composite structures have been actively investigated. However, relatively few attempts have been made to develop a filler that can effectively contribute to the performance enhancement of piezoelectric devices. In the present work, we introduce the fabrication and performance of the composite piezoelectric devices composed of Li-doped ZnO nanowires (Li: ZnO NWs) grown on the surface of MXene (Ti 3 C 2 ) via the hydrothermal process. Through this approach, a semiconductor−metal hybrid structure is formed, increasing the overall permittivity. Moreover, the Ti 3 C 2 layer can serve as a local ground in the composite so that the ferroelectric phase-transformed Li: ZnO NWs grown on its surface can be more effectively polarized during the poling process. In addition, the NW-covered surface of Ti 3 C 2 prevents the aggregation of metallic Ti 3 C 2 particles, promoting a more uniform electric field distribution during the poling process. As a result, the output performance of the piezoelectric nanogenerator (PENG) fabricated with a Li: ZnO NW/Ti 3 C 2 composite was greatly improved compared to that of the devices fabricated with Li: ZnO NWs without the Ti 3 C 2 platform. Specifically, the Li: ZnO NW/Ti 3 C 2 composite piezoelectric nanogenerator (PENG) demonstrated a twofold higher output power density (∼9 μW/cm 2 ) compared with the values obtained from the PENG devices based on Li: ZnO NWs. The approach introduced in this work can be easily adopted for an effective ferroelectric filler design to improve the output performance of the piezoelectric composite. KEYWORDS: piezoelectric nanogenerator (PENG), zinc oxide (ZnO) nanowires on MXene (Ti 3 C 2 ), hydrothermal growth, composite, phase transition

Synergistic Enhancement of Filtering Efficiency and Antibacterial Performance of a Nanofiber Air Filter Decorated with Electropolarized Lithium-Doped ZnO Nanorods

“…Therefore, X-ray photoelectron spectroscopy (XPS), photoluminescence (PL), and X-ray diffraction (XRD) analysis were performed to confirm the presence of Li. In the XPS spectra, although the peaks of Zn and O were found, the peak at ∼55 eV corresponding to Li was not detected because of the small amount of Li in ZnO NR, as also reported in other studies (Figure d). , Thus, the presence of Li indirectly confirmed by the shift of the O 1s peak, where the peak binding energy of O 1s was slightly higher in Li-doped ZnO NRs due to the oxygen atoms bounded to Li + ions (O–Li) (Figure e). , In PL spectra, undoped ZnO NRs exhibited emission peak at ∼400 nm, but redshift was observed in Li-doped ZnO NRs, which is consistent with previous reports (Figure f). , The PL spectra of broadband emission (500–800 nm) are associated with defects in ZnO crystals. The high intensity of yellow emissions (550–610 nm) observed after Li-doping was due to substitutional Li and interstitial Li in ZnO NRs .…”

“…30,31 In PL spectra, undoped ZnO NRs exhibited emission peak at ∼400 nm, but redshift was observed in Lidoped ZnO NRs, which is consistent with previous reports (Figure 1f). 32,33 The PL spectra of broadband emission (500− 800 nm) are associated with defects in ZnO crystals. The high intensity of yellow emissions (550−610 nm) observed after Lidoping was due to substitutional Li and interstitial Li in ZnO NRs.…”

A separator modified by barium titanate with macroscopic polarization electric field for high-performance lithium–sulfur batteries

“…23–25 However, the directions of spontaneous polarization in ferroelectric domains are generally inconsistent without the external electric field, which results in the insufficient interaction of ferroelectric materials with polysulfides. 26 In this regard, aligning the dipoles of ferroelectric materials is, therefore, essential to maximize the ferroelectricity of functionalized separators for LSBs.…”

“…See DOI: https://doi.org/ electric materials with polysulfides. 26 In this regard, aligning the dipoles of ferroelectric materials is, therefore, essential to maximize the ferroelectricity of functionalized separators for LSBs.…”

Construction of high-performance triboelectric nanogenerators based on the microstructures of conical nanoneedles

“…10 Therefore, improving the output performance of TENGs by material surface treatment is a key research topic and has become an urgent need in recent years. [11][12][13][14] By utilizing and constructing microstructures on the surface of the triboelectric layer and increasing the actual equivalent friction area, the friction coefficient and surface charge density of the triboelectric layer can be effectively improved. 15,16 At present, lithography, [17][18][19] etching technology, [20][21][22] and melt-blown technology 23,24 are widely used, which can effectively increase the surface charge density when the TENG works.…”