Mid Sweden University

Cellulose has shown great potential in the development of green triboelectric nanogenerators (TENG) [1]. 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 higher hydrophilic character; the films showed a (1- 10) diffraction peak of larger amplitude and higher apparent crystallinity. An open-circuit voltage (VOC) of up to ca. 260 V and a short-circuit current (ISC) of up to ca. 150 μA were measured for R-cellulose against polytetrafluoroethylene (as negative counter-layer). However, R-cellulose showed an increased VOC of 175% (from 88.1 V) against polydimethylsiloxane from methanol to n-pentanol. The corresponding ISC 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-layer that follow the surface structures increasing the effective contact area, are the leading reasons for a superior triboelectric performance.

[1] Zhang, R., Dahlström, C., Zou, H., Jonzon, J., Hummelgård, M., Örtegren, J., Blomquist, N., Yang, Y., Andersson, H., Olsen, M., Norgren, M., Olin, H. & Wang, Z.L. Adv. Mater. 32, 2002824, 2020; https://doi.org/10.1002/adma.202002824