For storing energy from renewable sources, scientists turn to antiferroelectrics

June 8, 2017 by Lisa Zyga feature
Hysteresis curves showing the electrical properties of antiferroelectric materials. Different colors represent different rare earth element compositions and the four graphs represent different electric field orientations. Credit: Xu et al. Published in Nature Communications

(Phys.org)—One of the greatest challenges in generating energy from renewable sources is finding a way to store the continuously fluctuating energy being produced. Batteries, supercapacitors, and most other energy-storage technologies typically can't respond quickly enough to the second-by-second fluctuations inherent in wind and solar energy sources. One device that does have a sufficiently fast response is electrostatic capacitors, but their drawback is their low energy density—they simply cannot store very much energy in a given volume.

Addressing this problem, researchers in a new study have shown in simulations that antiferroelectric based on bismuth can potentially exhibit very high densities (150 J/cm3), making them a promising candidate material for electrostatic capacitors. The results point to the possibility of a high-performance, environmentally friendly energy-storage device for .

The researchers, Bin Xu and Laurent Bellaiche at the University of Arkansas, and Jorge Íñiguez at the Luxembourg Institute of Science and Technology, have published a paper on their investigation of antiferroelectrics for energy storage in a recent issue of Nature Communications.

"We predict that rare-earth-substituted bismuth ferrite is a very promising system for high-power energy storage due to its high energy densities and good efficiencies, as well as its tuning flexibilities," Xu told Phys.org. "The model we developed connects the storage properties with fundamental energetic properties, which may lead to the discovery of new storage materials based on antiferroelectrics."

The key characteristic of antiferroelectric materials is that their adjacent electric dipoles point in opposite directions, which cancel out and result in a net zero polarization. As a result, the materials become ferroelectric under the application of a sufficiently large electric field. These electric properties can be easily tuned by controlling a variety of parameters.

In the new study, the scientists took advantage of this tunability to increase the energy and efficiency of a particular lead-free antiferroelectric compound (rare-earth-substituted BiFeO3). By changing the orientation of the electric field and the rare earth composition, the researchers predicted the potential for a very high energy density and high efficiency. They expect that tuning other parameters, such as strain or the addition of other rare-earth dopants, may improve these properties even further.

The simulations also enabled the researchers to develop a model to explain the connection between the and the tunable parameters investigated here. This model should also provide guidance for the development of antiferroelectric-based capacitors in the future. The researchers hope that these theoretical results will motivate efforts to experimentally demonstrate antiferroelectric materials with high energy densities.

"With the model, we are interested in assessing the properties of known and hypothetical antiferroelectrics via high-throughput first-principles calculations," Bellaiche said. "The promising candidates will be further examined, in collaboration with experimentalists and other theorists."

Explore further: Scientists take the first step toward creating efficient electrolyte-free batteries

More information: Bin Xu, Jorge Íñiguez, and L. Bellaiche. "Designing lead-free antiferroelectrics for energy storage." Nature Communications. DOI: 10.1038/ncomms15682

Abstract
Dielectric capacitors, although presenting faster charging/discharging rates and better stability compared with supercapacitors or batteries, are limited in applications due to their low energy density. Antiferroelectric (AFE) compounds, however, show great promise due to their atypical polarization-versus-electric field curves. Here we report our first-principles-based theoretical predictions that Bi1−xRxFeO3 systems (R being a lanthanide, Nd in this work) can potentially allow high energy densities (100–150 J cm−3) and efficiencies (80–88%) for electric fields that may be within the range of feasibility upon experimental advances (2–3 MV cm−1). In addition, a simple model is derived to describe the energy density and efficiency of a general AFE material, providing a framework to assess the effect on the storage properties of variations in doping, electric field magnitude and direction, epitaxial strain, temperature and so on, which can facilitate future search of AFE materials for energy storage.

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9 comments

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EmceeSquared
3 / 5 (2) Jun 08, 2017
"[...] supercapacitors [...] typically can't respond quickly enough to the second-by-second fluctuations inherent in wind and solar energy sources."

I have seen no evidence supercaps charge/discharge too slowly for solar and wind energy storage. In fact the opposite is true, especially on a 1 second scale.

"Dielectric capacitors, although presenting faster dis/charging rates and better stability compared with supercapacitors or batteries, are limited in applications due to their low energy density."

That statement from the researchers conflates caps and batteries in dis/charging and stability quality, so it's unclear that they're saying dielectrics are faster dis/charging than supercaps - which they aren't. Meanwhile supercaps are "super" because of their high energy density, >= electrolytics.

Antiferroelectrics might be the best, but those characterizations of supercaps baselines are wrong.
Shootist
1 / 5 (2) Jun 08, 2017
Mr Heinlein thought up Shipstones.

That was fiction.

The best energy storage we have, aside from the energy stored in the nucleus of the atom, is the solar energy stored in petroleum and coal. Cheaper too.

Carry on.
Captain Stumpy
4.2 / 5 (5) Jun 08, 2017
@shooty the paid shill of an idiot
The best energy storage we have, aside from the energy stored in the nucleus of the atom, is the solar energy stored in petroleum and coal. Cheaper too.
are you really that f*cking stupid?

1- leaded gas (you shouldn't have drank it)

2- what is cheap isn't always what is best, nor does being cheap impart any safety or security
this is especially true when you want to include continued biological activity in the future
(IOW, using a monosyllabic vocabulary that even you can comprehend: "pollution is bad")

so lets look at your brand of logic and apply it to everything else!

lets see...

ah, yes

salt water is cheap and plentiful, and it contains both salt and water, which are both required for life

therefore we must replace all human water sources with ocean water because it's cheap

LOL

and deniers wonder why we think they're so stupid?
unrealone1
not rated yet Jun 09, 2017
Why not just pump water up hill.
antialias_physorg
5 / 5 (2) Jun 09, 2017
Why not just pump water up hill.

There aren't hills (and big reservoirs at high elevations, and sources of water) everywhere. Duh.

And you will find that where these conditions are met such systems already exist. The amount of extra hydrostorage that can be built is fairly limited.
EmceeSquared
1 / 5 (1) Jun 09, 2017
unrealone1:
Why not just pump water up hill.


One big opportunity with renewable generation like wind and solar is that it can be distributed rather than centralized. This has reliability advantages as well as the possibility of avoiding transmission losses when located closer to consumption. Pumped storage is much more centralized. Batteries are much more distributed. They can be integrated with the generator or just distributed in better locations on the network.
MR166
2.3 / 5 (3) Jun 09, 2017
"are you really that f*cking stupid?"

Sorry Capt but Shootist is 100% correct. You might not particularly like fossil energy but but it is the best we have at this point in time.

Ad hominems do not make your case any stronger.
Captain Stumpy
5 / 5 (1) Jun 09, 2017
Sorry Capt but Shootist is 100% correct. You might not particularly like fossil energy but but it is the best we have at this point in time
@mr
no, he isn't, and it has nothing to do with what i like or dislike

for starters, that argument is essentially saying: yeah, you know that sh*tting in your house is bad, especially since you don't have indoor plumbing, but it gives off so much heat that it's helpful in the winter

so you've given up trying to do anything good because you want to believe the benefit outweighs the risks, regardless of the known problems with waste material and health

secondly: the problem isn't the cost of the subsidized energy, but rather the waste of the users and the refusal to put resources into finding a better alternative

I know PV's aren't for everyone, and they don't work on an industrial scale, but there are options

giving excuses doesn't make his case stronger

oh, and it's not ad hominem if it's demonstrably factually correct
Captain Stumpy
5 / 5 (1) Jun 09, 2017
@mr cont'd
You might not particularly like fossil energy but but it is the best we have at this point in time
and surely you can remember when this was also said about leaded fuel?
perhaps you need a refresher on basics, especially regarding pollution and it's adverse effects

moreover, as i stated: what is cheap isn't always what is best, nor does being cheap impart any safety or security

this is especially true when you want to include continued biological activity in the future

IOW, pollution = bad

EXAMPLE: salt water is cheap and plentiful, and it contains both salt and water, which are both required for life, but you don't see people drinking it to hydrate because it will dehydrate the body

this is a perfect analogy and example considering both your and shooty's argument as it's cheap/plentiful, it's "the best we have" at supporting life and it's also a pollutant in large amounts

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