University of Michigan (UM) researchers can now show a diverse mix of species improves the stability and fuel-oil yield of algal biofuel systems, as well as their resistance to invasion by outsiders. There’s been a dearth of algae news for quite some time now and this is the very best kind of news.

The UM scientists grew various combinations of freshwater algal species in 80 artificial ponds at UM’s E.S. George Reserve near Pinckney in the first large-scale, controlled experiment to test the widely held idea that biodiversity can improve the performance of algal biofuel systems in the field.

Overall, the researchers found that diverse mixes of algal species, known as polycultures, performed more key functions at higher levels than any single species – they were better at multitasking. But surprisingly, the researchers also found that polycultures did not produce more algal mass, known as biomass, than the most productive single species, or monoculture.

Study lead author Casey Godwin, a postdoctoral research fellow at U-M’s School for Environment and Sustainability said, “The results are key for the design of sustainable biofuel systems because they show that while a monoculture may be the optimal choice for maximizing short-term algae production, polycultures offer a more stable crop over longer periods of time.”

The team’s findings have been published in the journal Global Change Biology-Bioenergy.

In both phases of the study, colleagues at the UM College of Engineering used a technique called hydrothermal liquefaction to convert the algae into combustible oils, or biocrude, which can be refined to make transportation fuels like biodiesel.

Godwin explained, “First we evaluated different combinations of algae in the lab, and then we brought the best ones out to nature, where they were exposed to fluctuating weather conditions, pests, disease and all the other factors that have plagued algae-based fuel research efforts for 40 years.”

In their analysis of the algal samples collected during the 10-week E.S. George Reserve study, researchers compared the ability of monocultures and polycultures to do several jobs at once: to grow lots of algal biomass, to yield high-quality biocrude, to remain stable through time, to resist population crashes and to repel invasions by unwanted algal species.

Their analysis showed that the use of polycultures significantly delayed invasion by unwanted species of algae; that biocrude yields were significantly higher in the two- and four-species polycultures than in the monocultures; and that diverse crops of algae were more stable over time.

And while monocultures tended to be good at one or two jobs at a time, polycultures performed more of the jobs at higher levels than any of the monocultures, a trait called multifunctionality.

But at the same time, polycultures produced less biomass than the best-performing monoculture. And the use of polycultures had no significant effect on the magnitude and timing of sudden, sharp declines in algal production known as population crashes.

“Our findings suggest there is a fundamental tradeoff when growing algal biofuel,” said Cardinale, a professor at the UM School for Environment and Sustainability.

“You can grow single-species crops that produce large amounts of biomass but are unstable and produce less biocrude. Or, if you are willing to give up some yield, you can use mixtures of species to produce a biofuel system that is more stable through time, more resistant to pest species, and which yields more biocrude oil.”

In addition to Godwin and Cardinale, authors of the Global Change Biology paper are UM’s Aubrey Lashaway and David Hietala, and Phillip Savage of Pennsylvania State University.

Members of the same research team have published other recent papers that examine the benefits of diversity in algal biofuels systems for minimizing fertilizer use, recycling wastes, and improving the chemical properties of biocrude.

“Collectively, these results show how applying principles from ecology could help in the design of next-generation renewable fuel systems,” Godwin said.

Algae as a sustainable fuel has a great potential, but getting the cultivation matters worked out to production standards at prices that make competitive sense has been a multi-decade challenge. But little by little, research gets us closer and closer. Now if we could just get the interest level back up where the research news gets noticed.

Brookhaven National Laboratory scientists have synthesized a new cathode material from iron fluoride that surpasses the capacity limits of traditional lithium-ion batteries.

Scientists are searching for ways to improve lithium-ion batteries, the most common type of battery found in home electronics and a promising solution for grid-scale energy storage. Increasing the energy density of lithium-ion batteries could facilitate the development of advanced technologies with long-lasting batteries. Now, researchers have made significant progress toward achieving that goal.

Substituting the cathode material with oxygen and cobalt prevents lithium from breaking chemical bonds and preserves the material’s structure. Image Credit: Brookhaven National Lab. Click image for the largest view.

A collaboration led by scientists at the University of Maryland (UMD), the U.S. Department of Energy’s Brookhaven National Laboratory, and the U.S. Army Research Lab have developed and studied a new cathode material that could triple the energy density of lithium-ion battery electrodes.

Their research has been published in Nature Communications.

Xiulin Fan, a scientist at UMD and one of the lead authors of the paper said, “Lithium-ion batteries consist of an anode and a cathode. Compared to the large capacity of the commercial graphite anodes used in lithium-ion batteries, the capacity of the cathodes is far more limited. Cathode materials are always the bottleneck for further improving the energy density of lithium-ion batteries.”

The scientists at UMD synthesized a new cathode material, a modified and engineered form of iron trifluoride (FeF3), which is composed of cost-effective and environmentally benign elements – iron and fluorine. Researchers have been interested in using chemical compounds like FeF3 in lithium-ion batteries because they offer inherently higher capacities than traditional cathode materials.

Enyuan Hu, a chemist at Brookhaven and one of the lead authors of the paper explained, “The materials normally used in lithium-ion batteries are based on intercalation chemistry. This type of chemical reaction is very efficient; however, it only transfers a single electron, so the cathode capacity is limited. Some compounds like FeF3 are capable of transferring multiple electrons through a more complex reaction mechanism, called a conversion reaction.”

Despite FeF3’s potential to increase cathode capacity, the compound has not historically worked well in lithium-ion batteries due to three complications with its conversion reaction: poor energy efficiency (hysteresis), a slow reaction rate, and side reactions that can cause poor cycling life. To overcome these challenges, the scientists added cobalt and oxygen atoms to FeF3 nanorods through a process called chemical substitution. This allowed the scientists to manipulate the reaction pathway and make it more “reversible.”

Sooyeon Hwang, a co-author of the paper and a scientist at Brookhaven’s Center for Functional Nanomaterials (CFN) explained, “When lithium ions are inserted into FeF3, the material is converted to iron and lithium fluoride. However, the reaction is not fully reversible. After substituting with cobalt and oxygen, the main framework of the cathode material is better maintained and the reaction becomes more reversible.”

To investigate the reaction pathway, the scientists conducted multiple experiments at CFN and the National Synchrotron Light Source II (NSLS-II) – two DOE Office of Science User Facilities at Brookhaven.

First at CFN, the researchers used a powerful beam of electrons to look at the FeF3 nanorods at a resolution of 0.1 nanometers – a technique called transmission electron microscopy (TEM). The TEM experiment enabled the researchers to determine the exact size of the nanoparticles in the cathode structure and analyze how the structure changed between different phases of the charge-discharge process. They saw a faster reaction speed for the substituted nanorods.

Dong Su, a scientist at CFN and a co-corresponding author of the study said, “TEM is a powerful tool for characterizing materials at very small length scales, and it is also able to investigate the reaction process in real time. However, we can only see a very limited area of the sample using TEM. We needed to rely on the synchrotron techniques at NSLS-II to understand how the whole battery functions.”

At NSLS-II’s X-ray Powder Diffraction (XPD) beamline, scientists directed ultra-bright x-rays through the cathode material. By analyzing how the light scattered, the scientists could “see” additional information about the material’s structure.

Jianming Bai, a co-author of the paper and a scientist at NSLS-II said, “At XPD, we conducted pair distribution function (PDF) measurements, which are capable of detecting local iron orderings over a large volume. The PDF analysis on the discharged cathodes clearly revealed that the chemical substitution promotes electrochemical reversibility.”

Combining highly advanced imaging and microscopy techniques at CFN and NSLS-II was a critical step for assessing the functionality of the cathode material.

Xiao Ji, a scientist at UMD and co-author of the paper said, “We also performed advanced computational approaches based on density functional theory to decipher the reaction mechanism at an atomic scale. This approach revealed that chemical substitution shifted the reaction to a highly reversible state by reducing the particle size of iron and stabilizing the rocksalt phase.”

The scientists at UMD said this research strategy could be applied to other high energy conversion materials, and future studies may use the approach to improve other battery systems.

This is hopeful research with a grand result. But not anything is said about the processing to construct a new cathode. Perhaps it is simple, perhaps not. Manufacturers that look into this are going to want to know. We consumers looking for a three day cell phone are mighty curious too. Lets hope it scales up to industrial production soon.

Rice University engineers have developed a composite binder made primarily of fly ash, a byproduct of coal-fired power plants, that can replace Portland cement in concrete.

A scanning electron microscope image shows spherical particles in type C fly ash used by Rice University engineers to make cementless binder for concrete.  Image Credit: Multiscale Materials Laboratory/Rice University. Click image for the largest view.

According to Rice materials scientist Rouzbeh Shahsavari, who developed it with graduate student Sung Hoon Hwang the material is cementless and environmentally friendly. The fly ash binder does not require the high-temperature processing of Portland cement, yet tests showed it has the same compressive strength after seven days of curing. It also requires only a small fraction of the sodium-based activation chemicals used to harden Portland cement.

The research results paper has been published in the Journal of the American Ceramic Society.

More than 20 billion tons of concrete are produced around the world every year in a natural gas sourced manufacturing process that contributes 5 to 10 percent of the carbon dioxide to global emissions, surpassed only by transportation and energy as the largest producers of CO2.

Manufacturers often use a small amount of silicon- and aluminum-rich fly ash as a supplement to Portland cement in concrete.

Shahsavari, an assistant professor of civil and environmental engineering and of materials science and nanoengineering explained, “The industry typically mixes 5 to 20 percent fly ash into cement to make it green, but a significant portion of the mix is still cement.”

Previous attempts to entirely replace Portland cement with a fly ash compound required large amounts of expensive sodium-based activators that negate the environmental benefits. And in the end it was more expensive than cement,” he said.

The researchers used Taguchi analysis, a statistical method developed to narrow the large phase space – all the possible states – of a chemical composition, followed by computational optimization to identify the best mixing strategies.

This greatly improved the structural and mechanical qualities of the synthesized composites, Shahsavari said, and led to an optimal balance of calcium-rich fly ash, nanosilica and calcium oxide with less than 5 percent of a sodium-based activator.

“A majority of past works focused on so-called type F fly ash, which is derived from burning anthracite or bituminous coals in power plants and has low calcium content,” Shahsavari said. “But globally, there are significant sources of lower grade coal such as lignite or sub-bituminous coals. Burning them results in high-calcium, or type C, fly ash, which has been more difficult to activate.

“Our work provides a viable path for efficient and cost-effective activation of this type of high-calcium fly ash, paving the path for the environmentally responsible manufacture of concrete. Future work will assess such properties as long-term behavior, shrinkage and durability,” he said.

Shahsavari also suggested the same strategy could be used to turn other industrial waste, such as blast furnace slag and rice hulls, into environmentally friendly cementitious materials without the use of cement.

There are small mountains of fly ash out there to mine. Some deposits are somewhat dangerous to folks and property downhill and the deposits are concentrations of chemicals that when released are quite unpleasant to life. Discovering how to make something useful of it is a wonderful event.

As the “CO2 is destroying the planet” yarn wears out, something needs done with the remnants of coal system, which is mostly the fly ash. This news really cheers up the middle of the road folks between alarmists and deniers. Lets hope the future work proves up a far less expensive and better cement product.

A Korea Advanced Institute of Science and Technology (KAIST) research team has proposed a perovskite material that serves as a potential active material for highly efficient lead-free thin-film photovoltaic devices. This material is expected to lay the foundation to overcome previously known limitations of perovskite including its stability and toxicity issues.

The KAIST research team has proposed a perovskite material, Cs2Au2I6 (Cesium, Gold, Iodine) that serves as a potential active material for highly efficient lead-free thin-film photovoltaic devices.

Schematic of full solar cell device structure. Image Credit: KAIST. Click image for the largest view.

As strong candidates for next-generation high-efficiency photovoltaic cells, perovskite photovoltaic cells have a maximum photoconversion efficiency of 22%, comparable to high-performance crystalline silicon photovoltaic cells. In addition, perovskite-based cells can be fabricated at low temperatures, thereby bringing about dramatic cost reductions.

However, it has been noted that conventional organic-inorganic hybrid perovskite materials exhibit low stability, eventually degrading their performance and making them unfit for continued use. Moreover, their inclusion of lead has undermined their environmental friendliness.

So, a joint team led by Professor Hyungjun Kim from the KAIST Department of Chemistry and Professor Min Seok Jang from the School of Electrical Engineering has analyzed a previously discovered perovskite material, Cs2Au2I6, consisting of only inorganic substances and investigated its suitability for application in thin-film photovoltaic devices. Theoretical investigations suggests that this new perovskite material is not only as efficient but also more stable and environment friendly compared to the conventional perovskite materials.

For this analysis, the team developed multiscale multiphysics simulation frameworks. Atomic-scale first-principle quantum calculations were carried out to study the optical properties of the proposed material, and device-scale electromagnetic simulations were conducted to suggest that the material could indeed serve as a promising photovoltaic substance at the device level.

From this point onward, the research team plans to extend the study in two directions: an empirical study to apply the perovskite material in real-world photovoltaic cells and a theoretical analysis to find the optimal and highly stable material for photovoltaic cells

The team said, “Perovskite materials are highly efficient, but in order to completely replace the conventional solar cells, their stability and toxicity issues must first be resolved.” They added that this research is expected to accelerate related studies in pursuit of high-efficiency, environment-friendly perovskite materials.

This research is being led by post-doc researcher Lamjed Debbichi and master’s candidate Songju Lee. The research paper has been published and selected as the front cover article of Advanced Materials.

This looks good for the perovskite field. The concern right off is the Cesium, which isn’t particularly inexpensive and the gold which surely is not cheap. Iodine probably won’t have much impact. There are also the requisite matters of manufacturing, scaling up, longevity and recycling to work through. This looks like finally a lead free start for perovskite. Congratulations KAIST!

Swansea University scientists suggest that almost a third of the natural gas fueling UK homes and businesses could be replaced by hydrogen, a carbon free fuel, without requiring any changes to the nation’s boilers and ovens.

Hydrogen as a gas (H2), mixed with methane (CH4), results in Hydrogen-Enriched Natural Gas (HENG) which would help cut carbon emissions. Image Credit: Swansea University . Click image for the largest view.

The point is to cut back on carbon emissions. Over time such a move could cut UK carbon dioxide emissions by up to 18%.

The research paper has been published by the Royal Society of Chemistry.

Natural gas is used for cooking, heating and generating electricity. UK domestic gas usage accounts for 9% of UK emissions. In an effort to reduce annual carbon emissions, there is presently a concerted effort from researchers worldwide to offset our usage of natural gas.

Enriching natural gas with hydrogen is one way. Experiments have shown that modern-day gas appliances work safely and reliably with hydrogen-enriched natural gas as the fuel. It is already used in parts of Germany and the Netherlands, with a £600m government-backed trial in the UK taking place this year.

Natural gas naturally contains a small quantity of hydrogen, although current UK legislation restricts the allowed proportion to 0.1%.

The question the Swansea team investigated was how far they could increase the percentage of hydrogen in natural gas, before it became unsuitable as a fuel, for example because the flames became unstable.

The team, Dr Charles Dunnill and Dr Daniel Jones at the University’s Energy Safety Research Institute (ESRI), found:

  • An enrichment of around 30% is possible, when various instability phenomena are taken into account.
  • Higher percentages make the fuel incompatible with domestic appliances, due to hydrogen’s relatively low energy content, its low density, and a high burning velocity.
  • 30% enrichment by hydrogen nevertheless equates to a potential reduction of up to 18% in domestic carbon dioxide emissions.

Dr. Charles Dunnill of the Energy Safety Research Institute at Swansea University said, “Up to 30% of the UK’s gas supply can be replaced with hydrogen, without needing to modify people’s appliances. As a low carbon domestic fuel, hydrogen-enriched natural gas can cut our greenhouse gas emissions, helping the UK meet its obligations under the 2016 Paris Climate Change Agreement. Hydrogen-enrichment can make a difference now. But it could also prove a valuable stepping-stone towards a future, pure hydrogen, zero carbon gas network.”

These sorts of ideas are almost alarming. There are sound reasons that the natural gas supply has a limit of free hydrogen content. Dunnill, a safety guy, surely knows the effect that hydrogen has on other materials. Those risks and dangers have been mollified a bit, but are far from safe over time.

When we see a safety report about the materials used, like black pipe, assorted polymers, copper, aluminum, and brass your humble writer might not be so alarmed. Hydrogen gets away , where natural gas and propane stay in the lines. Remember, hydrogen burns really really fast. It might not be an explosive, but it acts like one. The military uses chemicals in the same zone for fuel air bombs. All right – it is alarming.


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