Power from water and graphene

Abstract

Since the birth of graphene in 2004, it has attracted great research interests of scientists. As the first true two-dimensional (2D) material, graphene has many advantages, such as large specific surface area, high intrinsic carrier mobility, strong mechanical strength, and superior flexibility. Graphene shows broad application prospects. As an important functionalized material, graphene oxide (GO) is 2D macromolecule rich in oxygen-containing functional groups. It has good hydrophilicity and is widely used as a chemical functionalized material in many related fields and applied to energy conversion and storage devices. However, converting the ideal properties of graphene and its derivatives into macrostructures or devices remains a challenge for scientists. The strong interaction between graphene sheets leads to their easy stacking, which greatly reduces their specific surface area and severely limits their efficient use of interfaces. Therefore, the applications of graphene in electronic devices, catalysis, energy storage and other fields have been greatly limited. The key to improve the performance of graphene is how to effectively prevent the stacking of graphene sheets. The assembly and processing of graphene with specific micro-/nano-morphology is conducive to better play the expertise of graphene, thus effectively enhancing the performance of graphene based devices. In this regard, there are lots of efforts have been devoted to the design of structure and morphology for graphene based materials. In the field of water-induced graphene energy converters, the interaction between water molecule and graphene is affected more by the morphology and microstructure change of graphene. As a new type of nano-material, graphene assembly can further expand its application scope. Due to the popularity of portable, flexible and wearable electronic devices, graphene materials have attracted a great deal of research interest from researchers in the field of energy converters. Graphene fibers and films are good solutions for portable needs. Graphene foam with compressibility also has important application value. In the field of hydropower, the moisture induced power generation of graphene oxide, most importantly, the construction of oxygen-containing radical gradients and the entry of water molecules. In a wet environment, water molecules can cause positive and negative charge separation, so that the potential difference appears on both sides of the material, resulting in the conversion of chemical potential energy into electrical energy. Moisture responds to the driver, depending on the affinity between the water and the GO layer. Water evaporation depends on the interaction between water molecules and carbon nanolayers. In this review, we summarized the current work of the major research teams at home and abroad on the assembly and processing of graphene, and the related work of graphene-based carbon materials in water-induced energy conversion, including the assembly and processing of graphene microstructures. As well as moisture power generation, moisture response drivers and water evaporation power generation, this will have guiding significance for the research of other types of materials in hydroelectric power generation. In the future, we still need to work hard in constructing the concentration and gradient of material functional groups to try to find out the actual applied electrical energy. In addition, many current carbon-based materials generate relatively low currents, and current researches on current increase are still continuing so that they can be applied in real life. Moreover, the interaction between carbon materials and water produces electricity. The mechanism still needs to be further explored, which will lay the foundation for future research on the production of electricity from other materials.