Most facile synthesis of Zn-Al:LDHs nanosheets at room temperature via environmentally friendly process and their high power generation by flexoelectricity

We report the zinc/aluminum layered double hydroxides (Zn-Al:LDHs) nanosheets that were most facilely synthesized at room temperature via an environmentally friendly process and demonstrate their ability to convert mechanical deformation into an electrical stimulus by flexoelectricity. The 1 mu m-thick Zn-Al:LDH nanosheets were most facilely synthesized for 2 h at room temperature after dipping the Al (10 at%)-doped ZnO (10AZO) (60 nm)/Au (10 nm)/10AZO (30 nm)-coated PET samples into the carbonated water that the CO2 in air was naturally captured in the water at room temperature. Based on the nanogenerators fabricated via facilely synthesized nanosheets, we observe a linear relationship between the output voltage and current generated by the centrosymmetric LDHs nanosheets and the curvature from bending, which is a direct evidence for flexoelectricity. We demonstrated the flexoelectric coefficient of our LDH nanosheet-based flexoelectric generators of 1.8 +/- 0.35 mu Cm-1. The output power generated from the LDH nanosheet-based generators via a pushing shows higher performance than that from state-of-the-art flexoelectric PZT-MWCNT-based and piezoelectric BaTiO3 nanotubes-based generators. These findings could pave the way to the practical exploitation for environmentally friendly synthesis of LDH nanosheets using the CO2 in air and for harvesting the energy via LDH nanosheets-based generators. (C) 2018 Elsevier Ltd. All rights reserved.