Scalable preparation of flexible heterogeneous graphene oxide structures for high-performance wet power generation

Abstract

Moisture-driven energy generation (MEG) has attracted great attention in recent years, and the interaction of functionalized nanomaterials with water offers the possibility of MEG. However, current MEG devices require specific open environments where the device stops generating power with the end of evaporation, preventing encapsulation and batch preparation. Herein, we propose a heterogeneous graphene oxide structure (HGOS) that achieves energy output through the interaction of water with functional groups. HGOS is a heterostructure of graphene oxide (GO)-reduced graphene oxide (rGO) films obtained by the thermal reduction of commercial GO films. Notably, the asymmetric interaction of water with oxygen groups on HGOS accelerates the directional migration of ions, generating potential differences and greater power densities. Hence, the open-circuit voltage of the packaged HGOS can be maintained around ∼0.96 V with an output power density of up to 879.2 μW cm⁻³. In addition to insights into the moisture-functional group interactions, HGOS has further shown potential for powering electronic devices in flexible fields. It can still maintain stable voltage and power output after bending 180°, with high flexibility, and is expected to supply energy for flexible devices. More importantly, HGOS can be easily prepared industrially by adding thermal reduction and roll-pressing units to the coating line for GO films. This batch-integrated preparation of HGOS devices can be used as an energy supply system for long-term operation in various natural scenarios, providing new strategies for new energy conversions.