The Emerging of Hydrovoltaic Materials as a Future Technology: A Case Study for China

Abstract

Water contains tremendous energy in various forms, but very little of this energy has yet been harvested. Nanostructured materials can generate electricity by water-nanomaterial interaction, a phenomenon referred to as hydrovoltaic effect, which potentially extends the technical capability of water energy harvesting. In this chapter, starting by describing the fundamental principle of hydrovoltaic effect, including water-carbon interactions and fundamental mechanisms of harvesting water energy with nanostructured materials, experimental advances in generating electricity from water flows, waves, natural evaporation, and moisture are then reviewed. We further discuss potential applications of hydrovoltaic technologies, analyze main challenges in improving the energy conversion efficiency and scaling up the output power, and suggest prospects for developments of the emerging technology, especially in China.

Why does water in porous carbon generate electricity? Electrokinetic role of protons in a water droplet-induced hydrovoltaic system of hydrophilic porous carbon

“…7 In particular, the exact mechanism of electricity generation from the interaction between water and nanostructured materials remains controversial because it is not easy to identify it with experimental measurements. The proposed principles of electricity generation in hydrovoltaics can be classied into two types, 24,25 i.e., water ow-induced (e.g., streaming potential 26 and electron drag 27 ) and ion ow-induced (e.g., gradient of protons or ions 11,28 ). The water ow mechanism is from the perspective of conventional streaming potential in a nanochannel or a porous medium.…”

“…7 In particular, the exact mechanism of electricity generation from the interaction between water and nanostructured materials remains controversial because it is not easy to identify it with experimental measurements. The proposed principles of electricity generation in hydrovoltaics can be classified into two types, 24,25 i.e. , water flow-induced ( e.g.…”

Nonlinear dependence (on ionic strength, pH) of surface charge density and zeta potential in microchannel electrokinetic flow

“…The electrokinetic (EK) involves the phenomena in which a liquid moves tangentially to a charged surface, where a better understanding gives rise to other related phenomenon such as electrophoresis, electroosmosis, and streaming potential. And gives rise to the foundation for many current advances in technological applications, such as microfluidic systems for lab-on-a-chip technologies [ 1 ], transportation in microchannel-based devices, chemical and biological detection [ [2] , [3] , [4] , [5] ]; nanofluid preparation and stabilization studies [ 6 , 7 ]; soil analyses [ 8 ], and nanostructure materials for energy harvesting [ [9] , [10] , [11] , [12] ]. Silica and silicate glass surfaces, for example, are the most common materials used to fabricate microchannels for chemical and biological transport processes [ [13] , [14] , [15] ].…”

All-Weather-Compatible Hydrovoltaic Cells Based on Al2O3 TLC Plates

“…Hydrovoltaic devices are an emerging technology that can extract power at the interface of porous materials in contact with water, whether the water is in the form of humidity, flowing water, from rainfall, wetting a surface through capillary action, followed by evaporation, and more. , Most studies have focused on maximizing the power output (maximizing open circuit voltage V oc and/or short circuit currents J sc ) using cost-effective carbon substrates. For example, in the pioneering work of Guo et al, 2.5 cm 2 soot substrates from burning fuels have been used to achieve 1 V under open circuit conditions; one of the highest efficiency hydrovoltaic devices to date .…”