Porous cellulose composite aerogel films with super piezoelectric properties for energy harvesting

Abstract

The piezoelectric effect is one of the most promising electromechanical coupling processes for mechanical energy conversion and energy harvesting. However, natural polymer based piezoelectric materials are of poor piezoelectric performance. we developed flexible porous piezoelectric aerogel films based on TEMPO-oxidized cellulose nanofibrils (TOCN) and MoS₂ nanosheets. Those aerogel films possessed large specific surface areas and abundant mesopores. Moreover, they exhibited very good piezoelectric properties when a field strength of 20 MV/m was used to polarize MoS₂ nanosheets and air in the mesopores. When assembled to piezoelectric nanogenerators (PENGs), a TOCN/MoS₂ aerogel film PENG containing 6 wt% of MoS₂ exhibited the best output performance. It generated an open circuit voltage of 42 V and a short-circuit current of 1.1 μA, a maximum area power density of 1.29 μW/cm² and a maximum volume power density of 0.143 μW/cm³. These features enable them to be promising piezoelectric materials for energy harvesting.

Keywords: Energy harvesting; MoS(2); Piezoelectric nanogenerators; Porous aerogel film; TEMPO-oxidized cellulose nanofibrils.