Regenerated cellulose properties tailored for optimized triboelectric output and the effect of counter-tribolayers
Christina Dahlström, Alireza Eivazi, Malin Nejström, Renyun Zhang, Torbjörn Pettersson, Haider Iftikhar, Orlando J. Rojas, Bruno Medronho, Magnus Norgren
Abstract
Abstract Cellulose has shown great potential in the development of green triboelectric nanogenerators. Particularly, regenerated cellulose (R-cellulose) has shown remarkably high output power density but the structural features and key parameters that explain such superior performance remain unexplored. In this work, wood cellulose fibers were dissolved in a LiOH(aq)-based solvent to produce a series of R-cellulose films. Regeneration in different alcohols (from methanol to n-pentanol) was performed and the films’ structural features and triboelectric performance were assessed. Nonsolvents of increased hydrophobicity led to R-cellulose films with a more pronounced (1–10) diffraction peak. An open-circuit voltage (V OC ) of up to ca. 260 V and a short-circuit current (I SC ) of up to ca. 150 µA were measured for R-cellulose against polytetrafluoroethylene (as negative counter-layer). However, R-cellulose showed an increased V OC of 175% (from 88.1 V) against polydimethylsiloxane when increasing the alcohol hydrocarbon chain length from methanol to n-pentanol. The corresponding I SC and output power also increased by 76% (from 89.9 µA) and by 382% (from 8.8 W m –2 ), respectively. The higher R-cellulose hydrophilicity, combined with soft counter-tribolayer that follow the surface structures increasing the effective contact area, are the leading reasons for a superior triboelectric performance. Graphic abstract