Supercharging Silicon Batteries – Powering Up LI Batteries


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The porosity of the nano-structured Tantalum (in black) enables the formation of silicon channels (in blue) allowing lithium ions to travel faster within the battery. The rigidity of the tantalum scaffold also limits the expansion of the silicon and preserve structural integrity. Credit: Okinawa Institute of Science and Technology Graduate University Nanoparticles by Design Unit

Scientists have designed a novel silicon-based anode to provide lithium batteries with increased power and better stability.

 

As the world shifts towards renewable energy, moving on from fossil fuels, but at the same time relying on ever more energy-gobbling devices, there is a fast-growing need for larger high-performance batteries. Lithium-ion batteries (LIBs) power most of our portable electronics, but they are flammable and can even explode, as it happened to a recent model of smartphone. To prevent such accidents, the current solution is to encapsulate the anode — which is the negative (-) electrode of the battery, opposite to the cathode (+) — into a graphite frame, thus insulating the lithium ions. However, such casing is limited to a small scale to avoid physical collapse, therefore restraining the capacity — the amount of energy you can store — of the battery.

Looking for better materials, silicon offers great advantages over carbon graphite for lithium batteries in terms of capacity. Six atoms of carbon are required to bind a single atom of lithium, but an atom of silicon can bind four atoms of lithium at the same time, multiplying the battery capacity by more than 10-fold. However, being able to capture that many lithium ions means that the volume of the anode swells by 300% to 400%, leading to fracturing and loss of structural integrity. To overcome this issue, OIST researchers have now reported in Advanced Science the design of an anode built on nanostructured layers of silicon — not unlike a multi-layered cake — to preserve the advantages of silicon while preventing physical collapse.

This new battery is also aiming to improve power, which is the ability to charge and deliver energy over time.

“The goal in battery technology right now is to increase charging speed and power output,” explained Dr. Marta Haro Remon, first author of the study. “While it is fine to charge your phone or your laptop over a long period of time, you would not wait by your electric car for three hours at the charging station.”

And when it comes to providing energy, you would want your car to start off quickly at a traffic light or a stop sign, requiring a high spike in power, rather than slowly creeping forward. A well-thought design of a silicone-based anode might be a solution and answer these expectations.img_0132-3

The idea behind the new anode in the Nanoparticles by Design Unit at the Okinawa Institute of Science and Technology Graduate University is the ability to precisely control the synthesis and the corresponding physical structure of the nanoparticles. Layers of unstructured silicon films are deposited alternatively with tantalum metal nanoparticle scaffolds, resulting in the silicon being sandwiched in a tantalum frame.

“We used a technique called Cluster Beam Deposition,” continued Dr. Haro. “The required materials are directly deposited on the surface with great control. This is a purely physical method, there are no need for chemicals, catalysts or other binders.”

“We used a technique called Cluster Beam Deposition,” continued Dr. Haro. “The required materials are directly deposited on the surface with great control. This is a purely physical method, there are no need for chemicals, catalysts or other binders.”

The outcome of this research, led by Prof. Sowwan at OIST, is an anode with higher power but restrained swelling, and excellent cyclability — the amount of cycles in which a battery can be charged and discharged before losing efficiency. By looking closer into the nanostructured layers of silicon, the scientists realized the silicon shows important porosity with a grain-like structure in which lithium ions could travel at higher speeds compared to unstructured, amorphous silicon, explaining the increase in power. At the same time the presence of silicon channels along the Ta nanoparticle scaffolds allows the lithium ions to diffuse in the entire structure. On the other hand, the tantalum metal casing, while restraining swelling and improving structural integrity, also limited the overall capacity — for now.

However, this design is currently only at the stage of proof-of-concept, opening the door to numerous opportunities to improve capacity along with the increased power.

“It is a very open synthesis approach, there are many parameters you can play around,” commented Dr. Haro. “For example, we want to optimize the numbers of layers, their thickness, and replace tantalum metal with other materials.”

With this technique paving the way, it might very well be that the solution for future batteries, forecast to be omnipresent in our lives, will be found in nanoparticles.

Story Source:

 

Material provided by Okinawa Institute of Science and Technology (OIST) Graduate UniversityNote: Content may be edited for style and length.

Journal Reference:

  1. Marta Haro, Vidyadhar Singh, Stephan Steinhauer, Evropi Toulkeridou, Panagiotis Grammatikopoulos, Mukhles Sowwan. Nanoscale Heterogeneity of Multilayered Si Anodes with Embedded Nanoparticle Scaffolds for Li-Ion BatteriesAdvanced Science, 2017; 1700180 DOI: 10.1002/advs.201700180
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Large Emissions from the Electric Car (EV) Battery Makers – Tesla an ‘Eco-Villain’?


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Electric power: When batteries are eco-villains in the production, according to a new report. Photo: Tomas Oneborg / SvD / TT

Huge hopes tied to electric cars as the solution to automotive climate problem. But the electric car batteries are eco-villains in the production. Several tons of carbon dioxide has been placed, even before the batteries leave the factory.

IVL Swedish Environmental Research Institute was commissioned by the Swedish Transport Administration and the Swedish Energy Agency investigated lithium-ion batteries climate impact from a life cycle perspective. There are batteries designed for electric vehicles included in the study. The two authors Lisbeth Dahllöf and Mia Romare has done a meta-study that is reviewed and compiled existing studies.

The report shows that the battery manufacturing leads to high emissions. For every kilowatt hour of storage capacity in the battery generated emissions of 150 to 200 kilos of carbon dioxide already in the factory. The researchers did not study individual bilmärkens batteries, how these produced or the electricity mix they use. But if we understand the great importance of play battery take an example: Two common electric cars on the market, the Nissan Leaf and the Tesla Model S, the batteries about 30 kWh and 100 kWh.

Even when buying the car emissions have already occurred, corresponding to approximately 5.3 tons and 17.5 tons, the batteries of these sizes. The numbers can be difficult to relate to. As a comparison, a trip for one person round trip from Stockholm to New York by air causes the release of more than 600 kilograms of carbon dioxide, according to the UN organization ICAO calculation.

Another conclusion of the study is that about half the emissions arising from the production of raw materials and half the production of the battery factory. The mining accounts for only a small proportion of between 10-20 percent.

Read more: “The potential electric car the main advantage”

The calculation is based on the assumption that the electricity mix used in the battery factory consists of more than half of the fossil fuels. In Sweden, the power production is mainly of fossil-nuclear and hydropower why lower emissions had been achieved.

The study also concluded that emissions grow almost linearly with the size of the battery, even if it is pinched by the data in that field. It means that a battery of the Tesla-size contributes more than three times as much emissions as the Nissan Leaf size. It is a result that surprised Mia Romare.

– It should have been less linear as the electronics used is not increased to the same extent. But the battery cells are so sensitive as production looks today, she says.

– One conclusion is that you should not run around with unnecessarily large batteries, says Mia Romare

The authors emphasize that a large part of the study has been about finding out what data is available and find out what quality they are. They have in many cases been forced to conclude that it is difficult to compare existing studies together.

 

We’ve been frustrated, but it is also part of the result, says Lisbeth Dahllöf.

His colleague, Mats-Ola Larsson at IVL has made a calculation of how long you have to drive a petrol or diesel before it has released as much carbon dioxide as battery manufacturing has caused. The result was 2.7 years for a battery of the same size as the Nissan Leaf and 8.2 years for a battery of the Tesla-size, based on a series of assumptions (see box below).

– It’s great that companies and authorities for ambitious environmental policies and buying into climate-friendly cars. But these results show that one should consider not to choose an electric car with a bigger battery than necessary, he says, noting that politicians should also take this on in the design of instruments.

An obvious part to look at the life cycle analysis is recycling. The authors note that the characteristics of the batteries is the lack of the same, since there is no financial incentive to send batteries for recycling, as well as the volumes are still small.

Cobalt, nickel and copper are recovered but not the energy required to manufacture electrodes, says Mia Romare and points out that the point of recycling the resource rather than the reduction of carbon emissions.

Peter Kasche the report originator Energy Agency emphasizes the close of the linear relationship between the battery size and emissions is important.

– Somehow you really get to see so as to optimize the batteries. One should not run around with a lot of kilowatt hours unnecessarily. In some cases, a plug-in hybrid to be the optimum, in other cases a clean vehicle battery.

So counted IVL

Mats-Ola Larsson has made a number of assumptions in the calculation of emissions from a battery of the Nissan Leaf size and a battery of Tesla’s size takes 2.7 and 8.2 years to “run together into” a normal petrol or diesel:

The average emissions of new Swedish cars in 2016 were 126 grams of carbon dioxide per kilometer. The value has been adjusted to 130 because some of the cars that are classified as electric vehicles are plug-in hybrids, which sometimes runs on fossil fuels.

While adoption of petrol and diesel have 18 percent renewable fuels, which affect emissions.

Average Mileage per year is 1224 mil under Traffic Analysis.

Dendrite-free lithium metal anodes using Nitrogen-doped graphene matrix – Solves Safety & Power Challenges


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Recently, Researchers in Tsinghua University have proposed a nitrogen-doped graphene matrix with densely and uniformly distributed lithiophilic functional groups for dendrite-free lithium metal anodes, appearing in the journal Angewandte Chemie International Edition.

Since lithium metal possesses an ultrahigh theoretical specific capacity (3860 mAh g-1) and the lowest negative electrochemical potential (-3.040 V vs. the standard hydrogen electrode), lithium metal has been regarded as the most promising electrode material for next-generation high-energy-density batteries. However, the application of lithium metal batteries is still not in sight. “Lithium dendrite growth has hindered the development of lithium metal anodes,” said Dr. Qiang Zhang, the corresponding author, a faculty at Department of Chemical Engineering, Tsinghua University. “Lithium dendrites that form during repeated lithium plating and stripping cycles can not only induce many ‘dead Li’ with irreversible capacity loss, but also cause internal short circuits in batteries and other hazardous issues.”

LI Dendrite separator“We found that a lithiophilic material with good metallic lithium affinity can guide the lithium metal nucleation. Therefore, designing a lithium-plating with a high surface area and lithiophilic surface makes sense for a safe and efficient ,” said Xiao-Ru Chen, an undergraduate student in Tsinghua University. “So we employed a nitrogen-doped graphene matrix with densely and uniformly distributed nitrogen containing to guide lithium metal nucleation and growth.”

“The nitrogen containing functional groups are lithiophilic sites, confirmed by our experimental and DFT calculation results. Lithium metal can plate with uniform nucleation during the charging process, followed by growth into dendrite-free morphology. While on the normal Cu foil-based anode, the nucleation sites are scattered, which may cause lithium dendrite growth more easily,” said Xiang Chen, a Ph.D. student at Tsinghua University.

With the lithiophilic nitrogen-containing functional groups, the N-doped graphene matrix can regulate the nucleation process of lithium electrodeposition. As a result, dendrite-free lithium metal deposits were obtained. Additionally, this matrix shows impressive electrochemical performance. The Coulombic efficiency of the N-doped graphene-based electrode at a current density of 1.0 mA cm-2 and a cycle capacity of 1.0 mAh cm-2 can reach 98 percent for nearly 200 cycles.

“We have proposed a new strategy based on lithiophilic site-guided nucleation to settle the tough dendrite challenge in this publication,” said Qiang. “Further research is required to investigate and control the lithium nucleation in lithium metal batteries. We believe that the practical application of lithium anodes can be finally realized.” The control of the process of plating with a lithiophilic matrix has shed a new light on all -based batteries, such as Li-S, Li-O2 and future Li-ion batteries.

Explore further: New battery coating could improve smart phones and electric vehicles

More information: Rui Zhang et al. Lithiophilic Sites in Doped Graphene Guide Uniform Lithium Nucleation for Dendrite-Free Lithium Metal Anodes, Angewandte Chemie International Edition (2017). DOI: 10.1002/anie.201702099

 

NREL’s Advanced Atomic Layer Deposition Enables Lithium-Ion Battery Technology


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NREL’s Agreement with Forge Nano helps fundamentally enhance lithium-ion battery safety, durability, and lifetime

The U.S. Department of Energy’s National Renewable Energy Laboratory (NREL) has entered into an exclusive license agreement with Forge Nano to commercialize NREL’s patented battery materials and systems capable of operating safely in high-stress environments. A particular feature of the technology is the encapsulation of materials with solid electrolyte coatings that can be designed to meet the increasingly demanding needs of any battery application.

These lithium-ion batteries feature a hybrid solid-liquid electrolyte system, in which the electrodes are coated with a solid electrolyte layer. This layer minimizes the potential for the formation of an internal short circuit between electrodes to prevent “thermal runaway,” or the uncontrolled increase in battery cell temperature that can result in a fire or an explosion.

In addition, coating of the electrode materials reduces the stress on traditional polymer separators that are currently necessary components in commercial lithium-ion batteries and can allow for thinner separators designed for higher power devices. This advancement has the potential to reduce both the cost and weight of the battery device, while substantially increasing safety and lifetime.

Lab-scale testing of NREL’s hybrid solid-liquid electrolyte system has shown increased electrode durability and reliability without compromised electrochemical performance. “The cells are less likely to fail, even in demanding, real-world conditions like high temperatures and fast recycle rates,” said Ahmad Pesaran, whose team of engineers in NREL’s Energy Storage group invented the technology.

Forge Nano 2017 AAEAAQAAAAAAAAdtAAAAJDgzZGI5OTYxLTcwYjUtNDdiMy05Yjc5LWFkZDZlOWU1OTg3YwForge Nano, formerly PneumatiCoat Technologies, is a Colorado-based company specializing in the scale-up and manufacturing of cost-effective Atomic Layer Deposition (ALD) encapsulated materials. Forge Nano presented its technology at the 2013 and 2017 NREL Industry Growth Forum, the nation’s premier clean energy investment event. A year later, NREL approached the company as a potential licensee after conducting a licensee search in the battery technology area.

“This license agreement will allow Forge Nano to offer further customized lithium-ion battery materials for high performance devices by utilizing our patented high-throughput ALD system that has already been successfully tested at the pilot scale and in large format pouch cells,” Paul Lichty, CEO of Forge Nano, said. “The incorporation of this technology into Forge Nano’s offering will lead to a substantial reduction in cost per unit energy of lithium-ion batteries.”

NREL has more than 800 technologies available for licensing. Companies interested in partnering to advance research on or commercialize renewable energy technologies can visit the EERE Energy Innovation Portal, which features descriptions of all renewable energy technologies funded by the Department of Energy’s Office of Energy Efficiency and Renewable Energy.

NREL is the U.S. Department of Energy’s primary national laboratory for renewable energy and energy efficiency research and development. NREL is operated for the Energy Department by The Alliance for Sustainable Energy, LLC.

Visit NREL online at www.nrel.gov

To learn more about Forge Nano visit: Forge Nano

UT Austin’s and Goodenough’s New ‘Solid Electrolyte Battery’ ~ Stumps Researchers – Video


  • Lithium-Ion battery inventor 94 year old John Goodenough has stumped researchers evaluating his recent discovery and resulting claims.
  • Greater Energy Density
  • Faster/ Rapid Re-Charging
  • SAFE! Non-Exploding
  • Low Cost Materials
  • Low Cost to Manufacture

Is the discovery the answer to much needed Energy Storage for Renewable Energies? The Electric Vehicle (EVs) ?

Watch the Video and tell us what you think? Leave us your Comments!

Using Nano-Structured conductive Polymer Gels to Improve Lithium-Io Battery’s Performance


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The electrode in lithium-ion (Li-ion) batteries is an integrated system in which both active materials and binder systems play critical roles in determining its final properties. In order to improve battery performance, a lot of research is focusing on the development of high-capacity active materials. However, without an efficient binder system, these novel materials can’t fulfill their potentials.

 

A group of researchers now has contributed to this field from a slight different aspect, developing a high-performance and general binder system for batteries. This entirely new binder system with a nano-architecture promotes both electron and ion transport, which enhances the energy per unit mass and volume of the electrode.This work by Guihua Yu group at University of Texas at Austin and Esther Takeuchi group at Stony Brook University, demonstrates a new generation of nanostructured conductive polymer gel based novel binder materials for fabrication of high-energy lithium-ion battery electrodes.

 

This gel framework could become a next-generation binder system for commercial Li-ion batteries.”Compared to conventional binder system which typically consists of conductive additive and polymer binder, our novel binder plays dual functionalities simultaneously combining conductive and adhesive features, thus greatly improving the better utility of active electrode materials,”Professor Yu tells Nanowerk.

“More importantly, owing to its unique 3D network structure, this gel binder promotes both electron and ion transport in electrode and improves the distribution of active particles, thus enhancing the rate performance and cycle life of battery electrodes.”He points out that this invention is important because it presents a new generation of powerful yet scalable binder materials for lithium ion batteries that show great potential in industrial manufacturing.This novel gel binder can overcome the drawbacks of conventional binder systems, leading to next-generation lithium ion battery with high performance.

The researchers have reported their findings in two papers in Nano Letters (“Nanostructured Conductive Polymer Gels as a General Framework Material To Improve Electrochemical Performance of Cathode Materials in Li-Ion Batteries”) and Advanced Materials (“A Tunable 3D Nanostructured Conductive Gel Framework Electrode for High-Performance Lithium Ion Batteries”).

 

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Schematic of synthetic and structural features of commercial lithium iron phosphate (C-LFP)/cross-linked polypyrrole (C-PPy) hybrid gel framework. The conductive polymer chains can be polymerized in situ with electrode materials and cross-linked by molecules with multiple functional groups, resulting in a polymeric network connecting all active particles. (Reprinted with permission by American Chemical Society) (click on image to enlarge)

“A traditional binder system in Li-ion battery electrodes is a binary hybrid with components acting separate functionalities,” explains Yu. “In such system, polymer binders such as polyvinylidene fluoride (PVDF) adhere the active materials and other additives together to hold the mechanical integrity while a conductive additive (usually carbon particles) ensures the conductivity of the entire electrode.”In these electrodes, electrons transport through chains of particles while ions move through the liquid or solid electrolyte that fills the pores of the electrode.

energy_storage_2013 042216 _11-13-1However, the conductive phases are randomly distributed, which may lead to bottlenecks and poor contacts that impede effective access to parts of the battery.And both organic and inorganic components tend to aggregate, which also negatively impact electron and ion transport.The team’s novel conductive gel binder can overcome these drawbacks and thus improve the rate and cyclic performance of Li-ion batteries.

The conductive polymer gels potentially could also be used for responsive/smart electronics such as biosensors, artificial skins and soft robotics.The scientific core of this work is that three-dimensional nanostructured conductive polymer gels can be built up by tunable molecule crosslinking and this unique conductive framework material can promote the electron/ion transport within battery electrodes.

“Firstly, our work provides a new method for synthesis of conductive polymer gel,” elaborates Yu. “Traditionally, conductive polymer gels are synthesized by template-based method, which usually results in low conductivity and poor mechanical properties. The method we developed is to crosslink conductive polymer chains with functional molecules with multiple functional groups, enabling a network, interconnected structure promoting high electronic conductivity and electrochemical activity.”

“Secondly, we demonstrated that this newly developed conductive polymer gel can be used as binder system and significantly improve conventional lithium-ion battery performance owing to their advantageous structural features,” he continues. “The ease of processability and excellent chemical and physical properties of these nanostructured conductive gels enable a new class of binder materials for fabricating next-generation high-energy lithium-ion batteries.”Although the researchers’ binder gel is mechanically strong, it lacks flexibility and stretchability.

The plan is to further modify the mechanical properties by tailoring the molecular backbones of conductive polymers through the addition of side chains or other building block polymers.The scientists further intend to demonstrate the versatility of their gel binders for other important electrode materials, such as some commercial electrode materials, as well as some next-generation ultrahigh-capacity materials, such as silicon, and sulfur.

by Michael Berger @ Nanowerk

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