Flexible regenerated cellulose/ZnO based piezoelectric composites fabricated via an efficient one-pot method to load high-volume ZnO with assistance of crosslinking

Flexible piezoelectric film has broad application in the energy devices and sensor field. Herein, a highly effective “one-pot method” was proposed to fabricate regenerated cellulose/ZnO piezoelectric composites, in which the preparation of regenerated cellulose (RC), in-suit polymerization of ZnO in RC and its cross linking can be carried out simultaneously. ZnO were in-situ synthesized from Zn2+ reduced by alkali from the dissolve system of cellulose. Simultaneously, the added zinc salt accompanied with acid degradation has promoted the dissolution of cellulose, existing a synergistic effect. In this synthetic process, ECH was used to crosslink cellulose molecules to obtain cross-linked regenerated cellulose (CRC), which enhanced regenerated cellulose framework for more uniform hydroxyl groups as growth sites, thereby further elevate growth content of piezoelectric ZnO distributed uniformly in the composite film. Consequently, the piezoelectric constant (d33) of the developed piezoelectric composite film with excellent tensile strength and flexibility reaches 26.8 ± 6.4 pC N−1. Without external high-voltage polarization, its piezoelectric output open-circuit voltage (VOC) and short-circuit current (ISC) was increased to 6.98 V and 610.27 nA. After polydimethylsiloxane (PDMS) was immersed in the CRC/ZnO aerogel to be CRC/ZnO/PDMS PENG, the piezoelectric output performance was further enlarged to be 10.02 V and 1032.57 nA, respectively, even with a high output stability. It can drive a LED and a small electronic screen, as well as has high sensitivity to pressure excitation, displaying high VOC and ISC up to 17 V and 1300 nA under the trampled state, respectively. The strategy has brought highly efficient assembly and high performance for the piezoelectric nanogenerator (PENG), directly providing a reference to other nanocellulose based PENG.