High‐Performance Flexible Graphene Oxide‐Based Moisture‐Enabled Nanogenerator via Multilayer Heterojunction Engineering and Power Management System

Abstract

Recently, there has been a surge of interest in nanogenerators within the scientific community because their immense potential for extracting energy from the surrounding environment. A promising approach involves utilizing ambient moisture as an energy source for portable devices. In this study, moisture‐enabled nanogenerators (MENGs) are devised by integrating heterojunctions of graphene oxide (GO) and reduced graphene oxide (rGO). Benefiting from the unique structure, a larger ion concentration gradient is achieved as well as a lower resistance, which leads to enhanced electricity generation. The resulting MENG generates a desirable open‐circuit voltage of 0.76 V and a short‐circuit current density of 73 µA cm−2 with a maximum power density of 15.8 µW cm−2. Notably, the designed device exhibits a high voltage retention of more than 90% after 3000 bending cycles, suggesting a high potential for flexible applications. Moreover, a large‐scale integrated MENG array is developed by incorporating flexible printed circuit technology and connecting it to a power management system. This integrated system can provide ample energy to operate an electronic ink display and drive a heart rate sensor for health monitoring. The outcomes of this research present a novel framework for advancing next‐generation self‐powered flexible devices, thereby demonstrating significant promise for future wearable electronics.

Moisture-Enabled Electric Generators Based on Electrospinning Silk Fibroin/Poly(ethylene oxide) Film Impregnated with Gradient-Structured Sericin

“…The upper surface of the film initially absorbs gaseous water molecules in moist air, and the oxygencontaining groups within the film retain the water molecules via hydrogen bonding. 49 Gaseous water molecules are converted to liquid form, releasing chemical energy (Figure 4c). Water ionizes the oxygenated group, resulting in the liberation of free protons.…”

“…A possible mechanism of the asymmetric SS-MEG is proposed (Figures a,b). The upper surface of the film initially absorbs gaseous water molecules in moist air, and the oxygen-containing groups within the film retain the water molecules via hydrogen bonding . Gaseous water molecules are converted to liquid form, releasing chemical energy (Figure c).…”

The Latest Advances in Ink-Based Nanogenerators: From Materials to Applications

“…Despite the tendency of current research to enhance current output at the expense of voltage, this trade-off limits the potential of these devices for power supply applications. In an effort to address this challenge, Fandi Chen et al [ 21 ] employed ultrasonic mixing techniques to incorporate varying ratios of rGO into GO suspensions, resulting in the fabrication of GO/rGO hybrid films with integrated GO and rGO heterostructures (as shown in Figure 21 a). This hybrid film leverages the synergistic effects of the heterojunctions to expand the ion concentration gradient and reduce resistance, significantly optimizing the output voltage and current of GO/rGO MEGs (rGO:GO = 1:10), as illustrated in Figure 21 b.…”

“… Overview of the latest developments in ink-based nanogenerators. Reprinted with permission from [ 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 ]. …”

“…( a ) Schematic illustration of the GO/rGO hybrid film structure. Reprinted with permission from [ 21 ]. Copyright 2023, John Wiley and Sons.…”