A breakthrough in solid-state battery tech

A breakthrough in solid-state battery tech


Due to safety and efficiency considerations, the world is turning to solid-state batteries (SSB), where the electrolyte — the material between the anode and cathode through which ions shuttle back and forth during charging and discharging — is solid, rather than liquid. As detailed in previous issues of  Quantum, SSBs have become the holy grail of battery technology.

Researchers are also working on all-lithium anodes. Negatively charged, the anode ‘donates’ electrons when the battery discharges. Lithium, a metal that has ‘spare’ electrons in the outermost ring of its atoms, is a good anode material but needs to be embedded (‘intercalated’) in some other material such as graphite. It would help to have an all-lithium anode because that would mean more electrons to be had on every charge-discharge cycle.

However, if you have an ‘embedded lithium’ anode and a solid electrolyte, it doesn’t give you the bang you want because the higher weight of the solid electrolyte (compared with liquid) nibbles away some efficiency.

So, the darling battery would be the one that has an all-lithium anode and a solid electrolyte. But there is one challenge yet.

As ions move from the anode to the cathode through the electrolyte (while discharging), the anode material (lithium) gets ‘pulled’ to form filaments called dendrites. If these dendrites touch the cathode, you have a short circuit and, likely, fire.

It was once believed that this dendrite formation would not happen if you use solid electrolytes instead of liquid, especially if the solid electrolyte’s rigidity (shear modulus) is twice that of lithium.

However, research revealed that dendrites grow even through solid electrolytes and, indeed, more than in liquid electrolytes. Researchers from Indian Institute of Science, Bengaluru, brought out a paper on the subject that says, “Lithium growth through solid electrolytes was observed at current densities as low as 100 microamperes per sq cm, much lower than current densities observed in liquid electrolytes.”

In essence, lithium cracking through the electrolyte, whether solid or liquid, is the biggest challenge in lithium-ion electrochemical batteries.

Prof Naga Phani Aetukuri at the solid state and structural chemistry unit of IISc and his student Vikalp Raj have delved into the problem of dendrite formation in solid-state Li-ion batteries and come up with a solution. In their research, they realised that microscopic ‘voids’ were developing in the lithium anode during discharge. The currents concentrated at the edges of these voids were about 10,000 times more than the average currents across the battery cell. This, they deduced, was creating stress on the solid electrolyte, leading to dendrite formation.

Now, the task was simply to prevent the voids. Aetukuri and Raj introduced an ultra-thin layer of a refractory (heat-resistant) metal between the lithium anode and the solid electrolyte. This ‘lithium-phobic interlayer’ delayed dendrite growth.

That is the science. Now, it is up to engineers to adopt it into a battery.

Published on

September 04, 2022



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The rising spectre of bio-crimes

The rising spectre of bio-crimes


You cannot make a nuclear bomb in your garage lab, but you can make other things that are equally devastating. If a scientific criminal cannot use physics for his deviousness, there is biology at hand.

Some might remember the 2001 ‘anthrax attacks’ — people received letters laced with anthrax, a killer bacterium; five died and several fell sick, and it was not until years later that the letters were traced to Dr Bruce Ivins, an American microbiologist, who took his life just before he was about to be arrested.

Handling deadly pathogens called for (note the past tense) a large set-up, a lot of money and high levels of technical expertise. Not anymore. Today, we are in an era of do-it-yourself (DIY) and home-made drugs — stuff that can be beneficial and harmful. In the last few years, scientists have been red-flagging these dangers but, by all accounts, nobody is sure how to counter them.

In recent times, scientists have uncorked a genie called ‘synthetic biology’. There is no standard definition of synthetic biology, but it essentially refers to creating organisms that are not found in nature and designed to do a task that we desire.

However, synthetic biology could also mean “re-programming” natural organisms to perform a task or modifying them to have new abilities, in the same way that computers can be re-programmed for specific functions. For example, the chimeric antigen receptor (CAR) technology, where immune cells can be engineered to recognise and attack cancer cells.

Mariam Elgabry of University College London, who has produced quite a few papers on bio-crime, points out that “a traditional biological system could, for example, be modified to behave like a sensor that gets activated and emits a signal in the presence of a toxin or disease signature, which is useful for medical diagnostics or environmental solutions”.

Synthetic biology, often described as the biology equivalent of the internet, has many promising and useful applications. Every country is looking at it seriously. In February, the Department of Biotechnology, Government of India, brought out an insightful ‘Foresight Paper’ calling for a policy on synthetic biology. But much like how the internet has engendered cybercrimes, synthetic biology, too, could be misused.

Easy access

Now, synthetic biology is not exactly new. It has been around as a concept for decades. But scientists are generally agreed that two factors have helped make it rather commonplace.

One is ‘next-generation sequencing’ (NGS), which refers to ultra-quick genome sequencing. According to Illumina, a company that offers NGS services, the technology “is used to determine the order of nucleotides in entire genomes or targeted regions of DNA or RNA”. With NGS, the cost of genome sequencing has come down to a few hundred dollars from thousands earlier — the ‘sub-$100’ milestone is tantalisingly within reach.

The second is the gene editing tool CRISPR, a Nobel Prize winning technology that helps alter a DNA and modify gene functions. This technology has rather democratised genetic engineering. TALEN is another gene editing tool. These genome editing kits “are being made openly available for purchase over the internet”, says a publication of the UK Home Office on ‘Future trends in security’.

Skilled amateurs as well as professional scientists can experiment with gene editing technology.

Says the Government of India’s ‘Foresight Paper’: “Synthetic biology involves large-scale synthesis of DNA which can create new pathogens from scratch, recreate old pathogens, or engineer naturally occurring organisms to become a threat to biosafety. If a sequence coding for a toxin is made available on the Internet and anyone can print the gene or pathogen.”

Add to this deadly concoction yet another poison — cybercrime — and the potential for crime increases by orders of magnitude. Mariam Elgabry et al in a 2020 paper on ‘Criminogenic potential of synthetic biology’, published in  Frontiers in Bioengineering and Biotechnology, say: “Synthetic biology integrates a diverse set of technologies to enable various applications that have enormous potential. While these were once restricted to specialised institutions, they are now freely available online through kits, bioinformatics tools and data.”

Evil experiments

So, what all can a criminal possibly do? Systematic evidence quantifying the crime opportunities posed by synthetic biology has been limited, says the Elgabry paper, but it divides the universe of criminal activities into eight categories — illegal gene editing, home-made bad drugs, genetic blackmail, neuro-hacking, bio-hacking, bio-discrimination, cyber bio-crime and bio-malware.

Each category can spawn a class of criminals specialising in it. For example, banned psychoactive drugs can be made at home. Earlier, one might have needed, say, a camouflaged agricultural field to grow poppy, but today you only need to understand how the poppy plant makes the psychoactive drug (the biosynthesis pathway). You can mimic the process in a lab. “In the event that a single psychoactive constituent is desired by the consumer and isolation from the native host is costly, total synthesis may be one strategy to establish a robust supply chain,” says a 2021 paper on ‘Biosynthesis and synthetic biology of psychoactive natural products’, by Cooper Jamieson et al.

A blackmailer, for instance, could easily obtain saliva samples of a father and son and do a paternity test; if negative, he could resort to blackmail. A neuro-hacker can manipulate the gut biome of a person and control the person’s brain, because there is a connection between the activities of the bacteria in the gut and the brain.

The list is practically endless.

The unfortunate part is that the world seems ill-equipped to deal with this rising spectre of bio-crime. In a recent paper on ‘The future of biotechnology crime: A parallel Delphi study with non-traditional experts’, Elgabry et al note that “forecasting biotechnology crime trends remains a challenge as future misuses become more sophisticated”.

The Foresight paper recognises the inadequacy of regulatory tools to deal with the emerging situation. “Many of the existing regulatory frameworks were developed in the context of “traditional” fields such as biotechnology and genetic engineering,” it says, adding that these “may have to be revised in order to cope with fresh challenges raised by synthetic biology”.

Published on

September 04, 2022



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Strong and stable steel for power plants

Strong and stable steel for power plants


Scientists at the International Advanced Research Centre for Powdered Metallurgy and New Materials (ARCI), Hyderabad, have developed a new method for making alloys of high strength. Austenitic steel, a special alloy, is among the promising structural materials used in power plants and reactors owing to excellent creep, corrosion and oxidation resistance compared with ferritic or ferritic–martensitic steels. It can withstand high temperatures, large stress, chemically reactive environments and intense neutron radiation fields, but suffers from inferior tensile strength and stress corrosion resistance at higher temperatures. Besides, one of the major concerns over its use in advanced nuclear power reactors is severe swelling due to irradiation, which can be reduced by introducing stable nano-oxide particles into the austenite matrix. The high-energy ball milling method used to disperse oxide particles in metal matrix invariably leads to powder sticking to the milling media and thus decreasing the milled powder yield. Using carbon-containing process control agents (PCA) such as stearic acid results in carbon pickup, which will promote coarsening of oxide particles.

A two-stage ball milling without the addition of any carbon-based PCA was employed by the ARCI scientists. The first-stage milling is aimed at dispersing the oxide particles into the ferrite matrix, which is the starting powder microstructure, and the second-stage milling is to transform the oxide dispersion strengthened (ODS) ferritic steel into austenitic ODS (AODS) steel by the addition of nickel.

Nitrogen gas was used as the PCA in both stages of milling to improve the milled powder yield. The alloy developed in this method was found to have one of the best combinations of yield strength and fracture strain.

Copper for silver

The shining grid lines you see in a photovoltaic solar module is silver, a costly metal, which is only expected to become dearer because the e-mobility and 5G telecom sectors will also want it. Can you use a cheaper metal in place of silver in PV cells?

Yes, says Dr Markus Glatthaar of the Fraunhofer Institute, Germany. Glatthaar, an expert in metallisation and structuring, has developed an electroplating process for the promising heterojunction technology to replace silver with copper. Copper is many times cheaper and more readily available than silver.

“We developed a special electroplating process that makes it possible to use copper instead of silver for the busbars,” explains Glatthaar. This even improves conductivity — the copper contact lines are particularly narrow on account of their laser structuring. The light-absorbing silicon layer experiences less shading than with silver lines. This improves electricity yield.

The Fraunhofer team also used aluminium as a masking layer. “We were able to adapt the process parameters and develop a special type of electrolyte which ensures that the aluminium’s extremely thin, native oxide layer can reliably fulfil its insulating function. This was an important milestone for the success of our research project,” says a press release from Fraunhofer Institute quoting Glatthaar.

Published on

September 04, 2022



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Study: Pfizer Covid pill showed no benefit in younger adults

Study: Pfizer Covid pill showed no benefit in younger adults


Pfizer’s Covid-19 pill appears to provide little or no benefit for younger adults, while still reducing the risk of hospitalization and death for high-risk seniors, according to a large study published Wednesday.

The results from a 109,000-patient Israeli study are likely to renew questions about the U.S. government’s use of Paxlovid, which has become the go-to treatment for Covid-19 due to its at-home convenience. The Biden administration has spent more than $10 billion purchasing the drug and making it available at thousands of pharmacies through its test-and-treat initiative.

The researchers found that Paxlovid reduced hospitalizations among people 65 and older by roughly 75 per cent when given shortly after infection. That’s consistent with earlier results used to authorize the drug in the U.S. and other nations.

But people between the ages of 40 and 65 saw no measurable benefit, according to the analysis of medical records.

Changing nature

The study has limitations due to its design, which compiled data from a large Israeli health system rather than enrolling patients in a randomized study with a control group — the gold-standard for medical research.

The findings reflect the changing nature of the pandemic, in which the vast majority of people already have some protection against the virus due to vaccination or prior infection. For younger adults, in particular, that greatly reduces their risks of severe Covid-19 complications. The Centers for Disease Control and Prevention recently estimated that 95 per cent of Americans 16 and older have acquired some level of immunity against the virus.

“Paxlovid will remain important for people at the highest risk of severe Covid-19, such as seniors and those with compromised immune systems,” said Dr. David Boulware, a University of Minnesota researcher and physician, who was not involved in the study. “But for the vast majority of Americans who are now eligible, this really doesn’t have a lot of benefit.” A spokesman for Pfizer declined to comment on the results, which were published in the New England Journal of Medicine.

Authorisation

The U.S. Food and Drug Administration authorised Paxlovid late last year for adults and children 12 and older who are considered high risk due to conditions like obesity, diabetes and heart disease. More than 42 per cent of U.S. adults are considered obese, representing 138 million Americans, according to the CDC.

At the time of the FDA decision, there were no options for treating Covid-19 at home, and Paxlovid was considered critical to curbing hospitalizations and deaths during the pandemic’s second winter surge. The drug’s results were also far stronger than a competing pill from Merck.

The FDA made its decision based on a Pfizer study in high-risk patients who hadn’t been vaccinated or treated for prior Covid-19 infection.

“Those people do exist but they’re relatively rare because most people now have either gotten vaccinated or they’ve gotten infected,” Boulware said.

Yet to be published

Pfizer reported earlier this summer that a separate study of Paxlovid in healthy adults — vaccinated and unvaccinated — failed to show a significant benefit. Those results have not yet been published in a medical journal.

More than 3.9 million prescriptions for Paxlovid have been filled since the drug was authorized, according to federal records. A treatment course is three pills twice a day for five days.

A White House spokesman on Wednesday pointed to several recent papers suggesting Paxlovid helps reduce hospitalizations among people 50 and older. The studies have not been published in peer-reviewed journals.

“Risk for severe outcomes from Covid is along a gradient, and the growing body of evidence is showing that individuals between the ages of 50 and 64 can also benefit from Paxlovid,” Kevin Munoz said in an emailed statement.

Administration officials have been working for months to increase use of Paxlovid, opening thousands of sites where patients who test positive can fill a prescription. Last month, U.S. officials further expanded access by allowing pharmacists to prescribe the drug.

The White House recently signaled that it may soon stop purchasing Covid-19 vaccines, drugs and tests, shifting responsibility to the private insurance market. Under that scenario, insurers could set new criteria for when they would pay for patients to receive Paxlovid.

Published on

August 25, 2022



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