By: Venkat Subramanian, University of Washington

This article refers to a recently published open access paper in the Journal of The Electrochemical Society, “Direct, Efficient, and Real-Time Simulation of Physics-Based Battery Models for Stand-Alone PV-Battery Microgrids.”

Tesla engineered a good electric car successfully by engineering a car design that can accommodate large battery stacks. Our hypothesis is that the current grid control method, which is a derivative of traditional grid control approaches, cannot utilize batteries efficiently.

In the current microgrid control, batteries are treated as “slaves” and are typically expected to be available to meet only the power needs. Typically, if grid optimization is done at the higher level, and then batteries are used as slaves, including models that predict fade can be used in a bi-level optimization mode (optimize grid operations and at every point in time, optimize battery operation). This way of optimization will not yield the best possible outcome for batteries.

In a recently published paper, we show that real-time simulation of the entire microgrid is possible in real-time. We wrote down all of the microgrid equations in mathematical form, including photovoltaic (PV) arrays, PV maximum power point tracking (MPPT) controllers, batteries, and power electronics, and then identified an efficient way to solve them simultaneously with battery models. The proposed approach improves the performance of the overall microgrid system, considering the batteries as collaborators on par with the entire microgrid components. It is our hope that this paper will change the current perception among the grid community.

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Researchers from Oregon State university have developed the first battery that uses only hydronium ions as the charge carrier, which the team believes could yield promising results for the future of sustainable energy storage.

Particularly, the researchers are interested in the area of stationary storage. This type of energy storage primarily refers to on-grid storage to harness power from intermittent sources, such as wind or solar, for later use in general distribution. Stationary energy storage is vital for the energy landscape to transition to more renewable types of energy because it will allow the electrical grid to continue to function when the sun goes down and the wind stops blowing.

This from Oregon State University:

Hydronium, also known as H3O+, is a positively charged ion produced when a proton is added to a water molecule. Researchers in the OSU College of Science have demonstrated that hydronium ions can be reversibly stored in an electrode material consisting of perylenetetracarboxylic dianhydridem, or PTCDA.

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Source: iStock

Today’s electronics consumers all have one thing in common: a desire for smartphones and other portable devices to have longer battery lives. Researchers from the University College Cork are looking to deliver just that with a new development that extends the cycle life of the lithium-ion battery to near record-length by using a key ingredient found in sunscreen.

The method, developed by ECS member and vice chair of the Society’s Electronics and Photonics Division, Colm O’Dwyer, and past members David McNulty and Elaine Carroll, uses titanium dioxide, which is a naturally occurring material capable of absorbing ultraviolet light.

When titanium dioxide is made into a porous substance, it can be charged and discharged over 5,000 times – or 13.5 years – without a drop in capacity.

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A new paper published in the Journal of The Electrochemical Society, “Mixed Conduction Membranes Suppress the Polysulfide Shuttle in Lithium-Sulfur Batteries,” describes a new battery membrane that makes the cycle life of lithium-sulfur batteries comparable to their lithium-ion counterparts.

The research, led by ECS Fellow Sri Narayan, offers a potential solution to one of the biggest barriers facing next generation batteries: how to create a tiny battery that packs a huge punch.

Narayan and Derek Moy, co-author of the paper, believe that lithium-sulfur batteries could be the answer.

The lithium-sulfur battery has been praised for its high energy storage capacity, but hast struggled in competing with the lithium-ion battery when it comes to cycle life. To put it in perspective, a lithium-sulfur battery can be charged between 50 and 100 times; a lithium-ion battery lasts upwards of 1,200 cycles.

To address this issue, the researchers devised the “Mixed Conduction Membrane” (MCM).

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In an effort to develop an eco-friendly battery, researchers from Ulsan National Institute of Science and Technology (UNIST) have created a battery that can store and produce electricity by using seawater.

The research is expected to dramatically improve cost and stability issues over the next five years, with researchers confident about commercialization.

The driving force behind the battery is the sodium found in seawater. Because sodium is so abundant, the researchers believe that this new system will be an attractive supplement to existing battery technologies. Because the seawater battery is cheaper and more environmentally friendly than lithium-ion batteries, the team says the seawater battery could provide an alternative option in large-scale energy storage.

This from UNIST:

Seawater batteries are similar to their lithium-ion cousins since they store energy in the same way. The battery extracts sodium ions from the seawater when it is charged with electrical energy and stores them within the cathode compartment. Upon electrochemical discharge, sodium is released from the anode and reacts with water and oxygen from the seawater cathode to form sodium hydroxide. This process provide energy to power, for instance, an electric vehicle.

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A new study published in the Proceedings of the National Academy of Sciences predicts that as climate change continues to accelerate average temperatures, electrical grids may be unable to meet peak energy needs by the end of the century.

The electrical grid is the central component of energy distribution and consumption. In order to upgrade this massive infrastructure to meet increasing demands, the researchers behind the study estimate nearly $180 billion would have to be invested in the U.S. grid.

This from the study:

As the electricity grid is built to endure maximum load, our findings have significant implications for the construction of costly peak generating capacity.

Read the full paper.

On top of acknowledging the correlation between increasingly hot days and higher demand for electricity (i.e. increased use of air conditioners and other cooling units), the study also acknowledges how the grid could react to this extra demand for electricity during peak hours of the day.

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By: Jackie Flynn, Stanford University

A battery made with urea, commonly found in fertilizers and mammal urine, could provide a low-cost way of storing energy produced through solar power or other forms of renewable energy for consumption during off hours.

Developed by Stanford chemistry Professor Hongjie Dai and doctoral candidate Michael Angell, the battery is nonflammable and contains electrodes made from abundant aluminum and graphite. Its electrolyte’s main ingredient, urea, is already industrially produced by the ton for plant fertilizers.

“So essentially, what you have is a battery made with some of the cheapest and most abundant materials you can find on Earth. And it actually has good performance,” said Dai. “Who would have thought you could take graphite, aluminum, urea, and actually make a battery that can cycle for a pretty long time?”

In 2015, Dai’s lab was the first to make a rechargeable aluminum battery. This system charged in less than a minute and lasted thousands of charge-discharge cycles. The lab collaborated with Taiwan’s Industrial Technology Research Institute (ITRI) to power a motorbike with this older version, earning Dai’s group and ITRI a 2016 R&D 100 Award. However, that version of the battery had one major drawback: it involved an expensive electrolyte.

The newest version includes a urea-based electrolyte and is about 100 times cheaper than the 2015 model, with higher efficiency and a charging time of 45 minutes. It’s the first time urea has been used in a battery. According to Dai, the cost difference between the two batteries is “like night and day.” The team recently reported its work in the Proceedings of the National Academy of Sciences.

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Image: University illustration / Michael Osadciw

Many researchers agree that microbial fuel cells have a range of promising applications. However, before they can reach widespread applications, researchers need to make them both cheaper and more efficient.

A team of researchers from the University of Rochester believe they’re making progress on that front with the development of a paper electrode.

Microbial fuel cells drive electric current by using bacteria and mirroring bacterial interactions found in nature. In the 21st century, microbial fuel cells found new application in their ability to treat wastewater and harvest energy through anaerobic digestion.

This from University of Rochester:

Until now, most electrodes used in wastewater have consisted of metal (which rapidly corrodes) or carbon felt. While the latter is the less expensive alternative, carbon felt is porous and prone to clogging. Their solution was to replace the carbon felt with paper coated with carbon paste, which is a simple mixture of graphite and mineral oil. The carbon paste-paper electrode is not only cost-effective and easy to prepare; it also outperforms carbon felt.

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Most of today’s batteries are made up of two solid layers, separated by a liquid or gel electrolyte. But some researchers are beginning to move away from that traditional battery in favor of an all-solid-state battery, which some researchers believe could enhance battery energy density and safety. While there are many barriers to overcome when pursing a feasible all-solid-state battery, researchers from MIT believe they are headed in the right direction.

This from MIT:

For the first time, a team at MIT has probed the mechanical properties of a sulfide-based solid electrolyte material, to determine its mechanical performance when incorporated into batteries.

Read the full article.

“Batteries with components that are all solid are attractive options for performance and safety, but several challenges remain,” says Van Vliet, co-author of the paper. “[Today’s batteries are very efficient, but] the liquid electrolytes tend to be chemically unstable, and can even be flammable. So if the electrolyte was solid, it could be safer, as well as smaller and lighter.”

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In an effort to purify water, researchers from the University at Buffalo are using carbon-dipped paper to make dirty water drinkable.

Those behind the research believe this new development could be a cheap and efficient way to address a global shortage in drinking water, specifically in developing areas.

(MORE: See what ECS members are doing to address global water and sanitation issues.)

“Using extremely low-cost materials, we have been able to create a system that makes near maximum use of the solar energy during evaporation,” says Qiaoqiang Gan, lead researcher. “At the same time, we are minimizing the amount of heat loss during this process.”

This from University at Buffalo:

The team built a small-scale solar still. The device, which they call a “solar vapor generator,” cleans or desalinates water by using the heat converted from sunlight. Here’s how it works: The sun evaporates the water. During this process, salt, bacteria, or other unwanted elements are left behind as the liquid moves into a gaseous state. The water vapor then cools and returns to a liquid state, where it is collected in a separate container without the salt or contaminants.

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