F20MRS Meeting: Molecular Design of Electrolytes for Lithium Metal Batteries

The ever-increasing demand to develop battery technologies with higher energy density. Batteries using a Li metal anode could deliver a higher operating voltage (around 0.1 ​V) than the graphite anode, which increases the energy density. The problem is by using the Li metal anode, Li dendrites start to grow as we charge/discharge the device, causing limited Coulombic Efficiency (CE) and severe side-reactions with the components in the routine liquid electrolytes. This is mainly because the active Li metal can react with nearly all dipolar aprotic organic solvents.

Anode-free lithium metal batteries are a type of lithium metal batteries that have shown superior energy density in comparison to regular Li-ion batteries. The active Li⁺ ions are initially stored in the cathode material, making the cathode less sensitive to moisture/air. During the initial charging process, the Li⁺ ions are extracted from the cathode and migrate to the anode and form a Li anode layer on the bare current collector. Subsequently, the active Li-ions are stripped from the in-situ formed Li anode and migrate back into the cathode during the discharging process 

So, the question is what is the bottleneck here?

Mr. Zhiao Yu and his co-workers at Stanford University have focused on a very important aspect of Li-metal batteries: chemically unstable and mechanically fragile solid-electrolyte interphase (SEI). The SEI layer is the Achilles heel as it easily cracks during cycling, leading to dendritic growth, “dead Li” formation, and irreversible Li loss. Their research focuses on tuning the SEI structure and quality, by molecular design of electrolyte.

In their work, Mr. Yu and co-workers target new solvent molecules that not only dissolve Li salt but also stay compatible when confronted with both Li metal anodes and high-voltage cathodes. fluorinated 1,4-dimethoxylbutane (FDMB), solely as the electrolyte solvent is paired with lithium bis(fluorosulfonyl)imide in a single-salt, single-solvent formulation (1 M LiFSI/FDMB) to enable stable and high-energy-density Li metal batteries.

Their Li|NMC fabricated full cells with limited-excess Li retain 90% capacity after 420 cycles with an average CE of 99.98%.

If you are interested in battery research and battery technologies, make sure to check out this talk using this link.

F20MRS Meeting: Exfoliation and Deposition of 2D Phosphorene for High-Performance Energy Storage

Phosphorous is a mysterious element that has different allotropes. white phosphorus, red phosphorus, black phosphorus, and a less significant violet phosphorous. Black phosphorus is the thermodynamically stable allotrope of phosphorous under ambient conditions. What is interesting about BP is that it has a layered structure and therefore it can be exfoliated into 2D monolayers that resemble graphene structure. 

Amin Rabei Baboukani and his co-workers developed an interesting approach for large scale production of 2D BP. They have used bipolar electrochemistry, by applying a high voltage to generate electrochemical reactions between two feeding electrodes while a conductive bipolar electrode is placed between them. The difference in the electric potential between the solution and the bipolar electrode drives the redox reactions on the cathodic and anodic poles.

 

 

 

 

 

 

The exfoliated BP structure resulting from this method is monolayer and the sheets show low defect concentrations. While this methodology opens up a new window for different applications, here Mr. Rabei Baboukani and co-workers have used the 2D BP monolayers for high-performance energy storage applications. Based on their experiments the capacitance of their 2D BP monolayers is superior to most of the 2D materials-based devices such as MXene, 2D MnO2, graphene or graphene oxide

You can watch this presentation using this link

F20MRS Meeting: Rechargeable Aluminum Batteries Based on 2D Transition Metal Carbide (MXene) Cathodes

The great shift of the energy industry to renewable and sustainable energy resources has attracted a lot of attention to the battery industry. The fast-growing market of EVs is expected to soon be comparable to gas-powered vehicles with the help of new environmental policies and government regulations. But what is the bottle-neck in developing Li-ion batteries? 

The safety concerns, limited resources, and high cost of Li-batteries alert the industry to look for alternatives. Aluminum has been introduced as a substitute to replace Li in battery technology. Rechargeable aluminum batteries with aluminum metal anode are considered as one of the most promising alternative energy storage systems to current Li-ion batteries. Aluminum is the most abundant metal in Earthís crust, and it can potentially offer three-electron redox reactions resulting in the highest theoretical volumetric capacity of 8040 mAh cm-3 among all metals. 

Dr. VahidMohammadi and his co-workers at Auburn University developed novel rechargeable aluminum batteries using two-dimensional (2D) V2CTx MXene as an intercalation-type cathode that has shown exceptional capacities and rate-capabilities. They show valuable insights about the possible reasons for the capacity loss, thermodynamics, and kinetics of Al3+ intercalation into V2CTx MXene cathode.

Dr. VahidMohammadi further talks about how designing new electrode architectures and modifying electrolyte composition, different 2D MXenes can deliver stable cyclic performance in the aluminum battery system.

 

 

 

 

 

Armin is also a talented sci-artist and has won multiple prizes in the Science as Art competition at MRS meetings.

You can watch his presentation using this Link.

 

Probing the probe: the key to atomic force microscope

In materials studies, atomic force microscopy (AFM) is one of the standard tools to characterize the surface of a material. Most of the time people use it to acquire a topographic image to access the surface morphologies. The development of the AFM technique is, however, still active and in the emerging phase (AFM was invented in 1986). At the heart of AFM, the probe plays a key role. 

Here’s a collection of talks that probe the design of the AFM probe in the joint Spring/Fall MRS:

F.MT02.03.03 Paddled Cantilever for AFM Beyond Topography by Dr. Hanna Cho from the Ohio State University

Cho group addresses the issue of artifacts that’s often accompanied by AFM measurements. By introducing a second micro-cantilever on the AFM probe, they demonstrate a great improvement of the artifacts and therefore help interpret the AFM images.

F.MT02.04.01 Conductive Colloidal Scanning Probe Microscopy by Dr. Christine Kranz from Ulm University

Kranz group focuses on developing colloidal probe technique that makes simultaneously physical and electrochemical mapping available.

 

 

 

 

 

Note: The list is not exhaustive and if you find relevant sessions, please let me know and I’d love to update the list!

To connect with Chiung-Wei: @cwhuang_sci

Learning from Nature - Engineered cells for arsenic-contaminated water remediation

F.SM01.09.06 Living Sorbents for Arsenic-Contaminated Drinking Water Remediation

Arsenic contamination is a growing problem in several parts of the world today. According to the FDA guidelines, Arsenic levels in Food and Dietary supplements must be regulated less than 10 ppb. But, arsenic levels in groundwater found in Bangladesh, Mexico, Argentina, Western USA, etc are rising to an alarming level. As arsenic poisoning can lead to adverse conditions to cardiovascular health, immune, and nervous system, to resolve this crisis, the presenter of this talk Yidan Bi(Brown University) looks for clues from natural detoxification mechanisms.

The toxicity of As(III) originates from its high affinity to the cysteine residues in proteins. So, the group engineered a benign strain of E. coli to overexpress specific fusion proteins which can impart an improved arsenic scavenging competency. This system is advantageous as it can easily sequester arsenic As(III) ions and bioaccumulate the arsenic. And the arsenic sorption capacity can be hastened to immobilize milligrams of arsenic in a few hours.

The Arsenic removal performance of the biosorbent cells was found to be much better compared to bayoxide in synthetic water as well as various other water matrices (such as altered pH and different salt concentrations). Moreover, the team was able to remove arsenic from water-matrices such as juice and wine. Lastly, to reduce secondary contamination, the bacteria from water is removed using magnetic-assisted labeling. Magnetic nanoparticles are used to label the engineered E. coli bio-sorbent cells which are then easily removed from the system using external magnets. Other solutions like pre-treatment or extensive removal of competing ions along with arsenic could increase the operation cost and unnecessarily eliminate other benign species from water. Comparatively, this method could be cost-friendly and accessible to rural areas that do not have access to fresh potable water and arsenic contaminant removal technology.

Thanks! Written by Arun Kumar. Follow us on Twitter for updates: @Arun Kumar @Materials_MRS

Mechanobiological Markers for Cancer Metastasis

S.SM01.05.01 Mechanobiological Markers for Cancer Metastasis

Finding a cure against cancer progression has been a compelling argument in recent times. GLOBOCAN 2018 estimate suggests that around 9.6 million cancer deaths worldwide occur each year. Amidst the current challenges in cancer research, figuring new biological markers for metastatic cancers is a major challenge. Advanced cancers in the breast and prostate tend to metastasize (travel to a distant location from the initial site and cause a secondary tumor) and move into the bone marrow making it terminal. The work presented by Dr. Dinesh Katti, from North Dakota State University discusses a novel in vitro tissue-engineered bio-mimetic scaffold to model breast and prostate cancers. And this way, the research team suggests that this scaffold would suffice as a mechanobiological measure for evaluating the disease progression.

First up the research group developed ‘in vitro test beds’ which mimic biocompatible conditions and suitable microenvironment as that of cancer at the bone site. This is possible with the help of tissue-engineered polymeric scaffolds which are complexed with polymer clay nanocomposites that enable biocompatible, cell proliferative, and adequate mechanical properties for biomimetic activity. The incorporation of long-chained amino acids and nano-sized clays into the polymer composite yielded higher biocompatible and mechanical properties respectively. So, the bio-mimetic bone could now house the mesenchymal stem cells and provide a niche for them to differentiate into other cell types. Then, the mesenchymal stem cells seeded onto the bone-mimetic scaffold grow along with prostate or breast cancer cells to differentiate into dense tumoroids which mimic the in vivo metastatic cancers.

Nanoindentation experiments were performed to learn the nanomechanical properties of the cancer cells at the bone scaffold (mimics the metastatic site). They deliberate that the tumoroid cells had a significantly lower load-displacement response than prostate cancer cells. The group also shows that the elastic modulus gradually decreases in the cells from tumoroids as cancer progresses. So, from the initial experiments, we can understand that the cell's mechanical properties play a differential role between metastatic cells or cancer cells. So, cytoskeletal dynamics were explored via in vitro experiments. Immunofluorescence imaging of F-actin and alpha-tubulin, two significant cytoskeletal markers were analyzed. And it was shown that while prostate cancer cells had the F-actin spread throughout the cytosol, metastatic tumoroid cells had the F-actin populate at only the cell boundaries. The volume of actin/cell is significantly lower in tumoroid cells than prostate cells, whereas there was an insignificant tubulin change between the cells. This could explain the cells becoming soft(or losing cytoskeletal content) to undergo EMT transition at the metastatic site. Similar data of actin levels were seen in low migratory type breast cancer MCF-7 cells, but high migratory MDA-MB-231 cells did not follow the data.

This helps the group conclude that the low migratory type cancer cells form tight junctions at the bone site(in which actin plays a major part) reducing the mechanical properties of the cells, while high migratory cancer cell types form loose clusters showing less change in mechanical properties of the cells. So, this research work could potentially be a mechanobiological marker for learning the progression of cancer metastasis.

Thanks! Written by Arun Kumar. Follow us on Twitter for updates: @Arun Kumar @Materials_MRS

Keep up! The Perovskite Database Project

Attention! Perovskite research community!

Have you ever felt overwhelmed to keep up to date with the published paper?

The Perovskite Database Project is initiated to help the researchers sort through the literature easier and faster. In F.EL08.07.08 Dr. Jacobsson explains how the published data is collected and demonstrates how to pinpoint the parameters that could be of research useful.

Picture: An example of The Perovskite Database Project: mapping out the solar cell efficiency associated with the year published. Users can further screen the performance by the parameters (deposition methods, materials, and substrates, etc.)

 

To connect with Chiung-Wei: @cwhuang_sci

Solo or not-solo STEM-preneur

When the global economic recession hit in 2008, I was approaching to finish my Master’s. Twelve years later, I’m about to wrap up my PhD and transition to next level career, a public health induced crisis infiltrates every inch of my life, and everyone’s on the planet. Different from the last time I chose to stay with academics, this year I’ve been searching for which path(s) reflect my passion and skillsets.

The MRS talk, F.BI01.02.05 “Useful Skill-Set Outside of the Employment Arena – Best Practices for the Solo Practitioner” captured my attention. The speaker, Dr. Sabol, builds and maintains a chemical consultant for 20 years to serve science and engineering-related professionals. He shares in the talk his perspective on the technical, business, and regulatory factors that were encountered when opening a start-up and maintaining a solo business.

“It’s great to have a job, but is there something you can do self-employed that you can get money for?”

As the world has shown us, the economy can turn down pretty quickly. He advises anyone to have marketable skills. This advice is emphasized quite a lot as I have heard about in industry-related job transition, which in my experience would need the patience to identify these unique and marketable characters. The process of self reflection, I believe, is applicable in any aspect of professional and even in personal growth.

“If you are good at something, you can be great at it when you put work into it.”

One of the takeaways from the talk is that if you are not enthusiastic about something, even though you are good at it, it wouldn’t be beneficial to spend time on it. In terms of putting your skillset into something that people will pay for, the speaker points out a few top essentials: (1) you learn something and you have fun in it, (2) you can generate revenue and, (3) you make a difference on someone else’s life.

With this perspective, I’m looking forward to building a path that reflects my passion and skillsets beyond the influences of the global pandemic.

Being aware of the issues around you will make it easier to define your core products and/or services. The following necessary marketing, communication, and regulatory requirements would come more natural once the fundamental decisions around a business are structured.

With this perspective, I’m looking forward to building a path that reflects my passion and skillsets beyond the influences of the global pandemic.

 

To connect with Chiung-Wei: Twitter or Instagram

Beyond SLA - Material Horizons for Volumetric Additive Manufacturing

I didn't catch the live lightning/flash session on Advances in 3D Printing for Medical Applications at Sunday 6 am local time, so I watched the recording after a leisurely breakfast and found an interesting presentation!

In stereolithography (SLA), UV light is projected onto photocurable resin layer by layer to 3D print an object. Layered defects present in traditional SLA-based techniques could be avoided in a volumetric additive manufacturing (VAM) technique called Computed Axial Lithography (CAL).

Here’s the big idea of how CAL works. As you may already know, a CT scan forms a 3D reconstruction by scanning an object with X-rays at different angles then computationally combining the 2D slices. Now imagine the inverse, where you have a 3D model of an object, then calculate the UV irradiation needed to cure the part from resin.

To accomplish CAL, the resin needs high optical penetration, high viscosity (above 1000 cP), and thresholded non-linear dose response. Below a critical threshold of accumulated UV dose, the resin does not cure. A high viscosity prevents the resin from flowing as the setup rotates during printing.

VAM has been demonstrated on a range of photocurable materials through CAL. Examples of acrylates include BPA-PEGDA, HDDA, TEGDA and PETA. Unlike acrylates, oxygen inhibition does not occur in the free-radical polymerization of thiol-ene. By adding a free radical scavenger 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO), thiol-ene resins with greater toughness than acrylates could be printed through CAL.

VAM was also used to 3D print gelatin methacryloyl (GelMA), a hydrogel used in biomedical applications. Incredibly low-modulus (<0.1 kPa) hydrogel made from 3% GelMA could be printed by CAL, with potential tissue engineering applications.

The development of CAL technology has also been aided by in silico experiments. Based on CT algorithms and photopolymerization factors such as resin absorptivity and photoinitiator, the spatial dose distribution of UV irradiation is estimated. Computer simulations of photocuring enabled optimization of printing parameters.

Indeed, this presentation has widened my horizons. 

P.S. protip: on the virtual MRS Meeting platform, click on the "Files" tab to view the sequence of presentations in the live session. 

Microplastics and microbes

Ever since microsized particles fibers of plastics were found in the sea, microplastics have gained notoriety for bioaccumulation in animals such as oysters, fish and birds. Microplastics and even nanoplastics are now all-pervasive, found in the Himalayan highlands, the Antarctica, table salt, and even in the air we’re breathing. Have you wondered if micro-organisms would be impacted by microplastics or resilient against them?

Mary Machado from Cornell University and coworkers exposed Synechococcus sp. PCC7002, a photosynthetic cyanobacterium, to polyethylene (PE) microparticles and nanoparticles. RNA electrophoresis results showed signs of oxidative stress. Based on cryo-SEM observations, exposure to PE nanoparticles caused more polysaccharide formation.

Microplastics and nanoplastics was found to affect bacterial cell viability, gene expression and morphology. The effects of microplastics and nanoplastics could be more far-reaching to the planet’s ecosystem than I previously imagined, from the largest creatures to the smallest microbes…

Link to OnDemand Spring symposium S.NM04.03.04 Effects of Polyethylene Particles from 0.2 μm - 0.9 μm in Size on Synechococcus sp. PCC 7002