Water-evaporation-induced electricity with nanostructured carbon materials

Abstract

Water evaporation is a ubiquitous natural process that harvests thermal energy from the ambient environment. It has previously been utilized in a number of applications including the synthesis of nanostructures and the creation of energy-harvesting devices. Here, we show that water evaporation from the surface of a variety of nanostructured carbon materials can be used to generate electricity. We find that evaporation from centimetre-sized carbon black sheets can reliably generate sustained voltages of up to 1 V under ambient conditions. The interaction between the water molecules and the carbon layers and moreover evaporation-induced water flow within the porous carbon sheets are thought to be key to the voltage generation. This approach to electricity generation is related to the traditional streaming potential, which relies on driving ionic solutions through narrow gaps, and the recently reported method of moving ionic solutions across graphene surfaces, but as it exploits the natural process of evaporation and uses cheap carbon black it could offer advantages in the development of practical devices.

A Filter Paper‐Based Nanogenerator via Water‐Drop Flow

“…[29] In brief, 1 g of MWCNTs was uniformly dispersed into 40 mL mixture solution of sulfuric acid and nitric acid (the volume ratio was 3:1). [29] In brief, 1 g of MWCNTs was uniformly dispersed into 40 mL mixture solution of sulfuric acid and nitric acid (the volume ratio was 3:1).…”

“…Therein, it is an effective idea to fabricate a nanogenerator for harvesting various energies. Meanwhile, the modified multiwalled carbon nanotubes (MWCNTs) [29,43,44] was selected as the current collector of the filter paper with the merits of fiber-like nanostructure, robust ohmic contact, and superior hydrophilicity. and cations (Ca 2+ , Mg 2+ , K + , Na + , etc.)…”

“…[16] In addition, the as-harvested energy has various resources, such as wind, [17][18][19] heat energy, [20,21] solar power, [22] vibration, [23,24] mechanical energy, [25] electromagnetic waves, [26] chemical energy, [27] and water energy. [11,28,29] Therein, the nanogengerator induced from water-flow [30][31][32][33][34] and water evaporation [29,35] is a majority part of the water energy nanogenerator. Generally, the energy-produced principle from water-flow and water evaporation could be divided into two categories according to the surface properties of the nanogenerator.…”

Structure and Dynamics of Water at Carbon-Based Interfaces

“…Specifically it decreases for CNT with diameters > 1 nm, e.g., 2r (8,8) = 1.1 nm for Equation (3), and increases when the diameter is 2r (6,6) …”

“…The knowledge of microscopic properties of confined water is of central importance in a wide range of physical systems and processes such as electrochemical systems [1,2], corrosion [3,4], solar energy conversion [5], energy-harvesting and generation devices [6], meteorology [7] or in a wide variety of biosystems (lipid membranes, proteins, etc.) [8,9], including protein adsorbed on graphene at cryogenic temperatures [10], to mention only a few.…”