Solar Energy

Synthetic tree enhances solar steam generation for harvesting drinking water

Published

4 years ago

June 23, 2021

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Synthetic tree enhances solar steam generation for harvesting drinking water

About 2.2 billion people globally lack reliable access to clean drinking water, according to the United Nations, and the growing impacts of climate change are likely to worsen this reality.

Solar steam generation (SSG) has emerged as a promising renewable energy technology for water harvesting, desalination, and purification that could benefit people who need it most in remote communities, disaster-relief areas, and developing nations. In Applied Physics Letters, by AIP Publishing, Virginia Tech researchers developed a synthetic tree to enhance SSG.

SSG turns solar energy into heat. Water from a storage tank continuously wicks up small, floating porous columns. Once water reaches the layer of photothermal material, it evaporates, and the steam is condensed into drinking water.

One major challenge in scaling up SSG technology is the limit in the capillary force beyond a certain column height, when the water cannot wick fast enough to keep up with the evaporation process. The capillary force, based on the surface tension that causes water to “climb” a porous paper towel, drives the water toward the evaporator.

Inspired by mangrove trees thriving along coastlines, the researchers bypassed this hurdle by creating a synthetic tree to replace the capillary action with transpiration, the process of water movement through a plant and its evaporation from leaves, stems, and flowers. Transpiration can pump water up insulating tubes of any desired height.

In real trees, transpiration begins at the roots, which suck up water through hollow vessels made from xylem tissue. As the water warms, it releases as vapor through pores on the underside of leaves.

The synthetic tree consists of a 19-tube array, covered by a nanoporous ceramic disk, which serves as the leaf. Each plastic tube, imitating the xylem conduits, is 6 centimeters high, just under 2.5 inches, with an inner diameter of 3.175 millimeters, about a tenth of an inch.

The setup enables the evaporating interface to thermally separate from the bulk water in the tank, so the evaporator does not dry out. Water evaporating from the disk is replenished by suction, which continuously pumps more water from a bottom tank up the tube array.

“We expect our tree-based solar steam generator will be of interest for applications in underground water extraction and purification,” author Jonathan Boreyko said. “The ultimate goal is to achieve a suction pressure strong enough to pull ocean water through a salt-excluding filter without requiring a mechanical pump, analogous to how mangrove trees are able to grow in ocean water.”

Future research could focus on fabricating taller trees, adding more leaves to increase the area over which evaporation occurs, and incorporating desalination membranes at the tube inlets to prevent salt buildup.

Research Report: “Synthetic trees for enhanced solar evaporation and water harvesting”

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Solar Energy

Pioneering advancements in solid-state battery technology for energy storage

Published

1 hour ago

December 22, 2024

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Pioneering advancements in solid-state battery technology for energy storage

by Riko Seibo

Tokyo, Japan (SPX) Dec 23, 2024

Recent strides in solid-state battery technology are setting the stage for a transformative era in energy storage. These advancements hold promise for revolutionizing electric vehicles and renewable energy systems through improved performance and safety. A focus on electrolyte innovation has been key to this progress, enabling the development of high-performance all-solid-state batteries (ASSBs).

A new review paper provides a comprehensive summary of advancements in inorganic solid electrolytes (ISEs), materials that are central to ASSBs. Researchers examined the roles of oxides, sulfides, hydroborates, antiperovskites, and halides not only as electrolytes but also as catholytes and interface layers, which collectively enhance battery performance and safety.

“We highlighted the recent breakthroughs in synthesizing these materials, honing our attention on the innovative techniques that enable the precise tuning of their properties to meet the demanding requirements of ASSBs,” said Eric Jianfeng Cheng, associate professor at Tohoku University’s Advanced Institute for Materials Research (AIMR). “Precise tuning is crucial for developing batteries with higher energy densities, longer life cycles, and better safety profiles than conventional liquid-based batteries.”

The review also delves into the electrochemical properties of ISEs, including ionic conductivity, stability, and electrode compatibility. Researchers evaluated current ASSB models and suggested emerging strategies that could drive the next generation of energy storage solutions.

However, challenges persist in the development of ASSBs, notably the limited compatibility between ISEs and electrodes, which can trigger interfacial reactions. Addressing these compatibility issues is vital to improving battery efficiency and longevity. The review outlines these challenges and provides insights into efforts aimed at overcoming them.

“Our comprehensive review underscores the importance of continued research and development in the field of solid-state batteries. By developing new materials, improving synthesis methods, and overcoming compatibility issues, current efforts are driving innovation toward practical ASSBs that could transform how we store and use energy,” Cheng added.

Research Report:Inorganic solid electrolytes for all-solid-state lithium/sodium-ion batteries: recent developments and applications

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Solar Energy

Buried interface engineering drives advances in tin-lead perovskite solar cell efficiency

Published

2 days ago

December 20, 2024

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Buried interface engineering drives advances in tin-lead perovskite solar cell efficiency

by Simon Mansfield

Sydney, Australia (SPX) Dec 20, 2024

A team led by Prof. Meng Li from Henan University’s School of Nanoscience and Materials Engineering has unveiled an innovative approach to overcoming stability and efficiency challenges in tin-lead (Sn-Pb) perovskite solar cells. The researchers’ work focuses on optimizing the buried hole-selective interface using a specially designed self-assembled material, offering major implications for single-junction and tandem solar cell technologies.

Tin-lead perovskites are valued for their narrow bandgap properties, which position them as key materials for producing high-efficiency solar cells. However, energy level mismatches and degradation at the buried interface have constrained both their performance and long-term stability. Addressing these issues, Prof. Meng’s team designed a boronic acid-anchored hole-selective contact material, 4-(9H-carbazole-9-yl)phenylboronic acid (4PBA).

Compared to conventional materials, 4PBA demonstrated superior stability and compatibility at the substrate surface. Its high adsorption energy of -5.24 eV and significant molecular dipole moment (4.524 D) improved energy level alignment between the substrate and perovskite layer, facilitating efficient charge extraction. Additionally, the interface engineered using 4PBA improved perovskite crystallization and substrate contact, reducing defects and non-radiative recombination.

These advancements enabled Sn-Pb perovskite solar cells incorporating 4PBA to achieve a power conversion efficiency (PCE) of 23.45%. The material’s reduced corrosiveness also mitigated the degradation effects typically caused by PEDOT:PSS, a widely used hole-transport material, enhancing chemical stability and storage durability. The cells retained 93.5% of their initial efficiency after 2,000 hours of shelf storage.

“This approach offers a practical path to enhancing both the efficiency and stability of Sn-Pb perovskite solar cells, addressing energy level mismatches and interfacial stability concerns,” the research team commented.

The findings provide a foundation for advancing efficient and stable Sn-Pb perovskite solar cells and highlight the importance of interface engineering in next-generation photovoltaic technologies.

Research Report:Buried Hole-Selective Interface Engineering for High-Efficiency Tin-Lead Perovskite Solar Cells with Enhanced Interfacial Chemical Stability

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Solar Energy

New solar material advances green hydrogen production

Published

2 days ago

December 20, 2024

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New solar material advances green hydrogen production

by Simon Mansfield

Sydney, Australia (SPX) Dec 20, 2024

Researchers in nano-scale chemistry have made a significant stride in advancing the sustainable and efficient production of hydrogen from water using solar energy.

A collaborative international study led by Flinders University, with partners in South Australia, the US, and Germany, has identified a novel solar cell process that could play a crucial role in photocatalytic water splitting for green hydrogen production.

The research introduces a new class of kinetically stable ‘core and shell Sn(II)-perovskite’ oxide solar material. Paired with a catalyst developed by US researchers under Professor Paul Maggard, this material shows potential as a catalyst for the essential oxygen evolution reaction, a key step in generating pollution-free hydrogen energy.

The findings, published in The Journal of Physical Chemistry C, offer new insights into the development of carbon-free hydrogen technologies, leveraging renewable and greenhouse-gas-free power sources for high-performing and cost-effective electrolysis processes.

“This latest study is an important step forwards in understanding how these tin compounds can be stabilised and effective in water,” said Professor Gunther Andersson, lead author from the Flinders Institute for Nanoscale Science and Technology.

Professor Paul Maggard, from Baylor University, added, “Our reported material points to a novel chemical strategy for absorbing the broad energy range of sunlight and using it to drive fuel-producing reactions at its surfaces.”

Tin and oxygen compounds like those used in the study are already applied in diverse fields such as catalysis, diagnostic imaging, and therapeutic drugs. However, Sn(II) compounds are typically reactive with water and dioxygen, limiting their technological potential.

Global solar photovoltaic research continues to focus on developing cost-effective, high-performance perovskite-based systems as alternatives to conventional silicon and other existing technologies.

Hydrogen, often touted as a clean fuel, can be produced through various processes, including electrolysis powered by renewable energy, thermochemical water splitting using concentrated solar power, or waste heat from nuclear reactors. While fossil fuels and biomass can also generate hydrogen, the environmental and energy efficiency depends largely on the production method.

Solar-driven hydrogen production, which uses light to initiate the process, is emerging as a promising alternative for industrial-scale hydrogen generation.

This study builds on earlier research led by Professor Maggard, initially at North Carolina State University and now at Baylor University, and includes contributions from University of Adelaide experts such as Professor Greg Metha and collaborators from Universitat Munster in Germany. Professor Metha’s work explores the photocatalytic activity of metal clusters on oxide surfaces for reactor technologies.

Research Report:Chemical and Valence Electron Structure of the Core and Shell of Sn(II)-Perovskite Oxide Nanoshells