New Long Awaited ‘next generation wonder material’ “Graphyne”created in Bulk for first time at the U of Colorado Boulder

For over a decade, scientists have attempted to synthesize a new form of carbon called graphyne with limited success. That endeavor is now at an end, though, thanks to new research from the University of Colorado Boulder.

Graphyne has long been of interest to scientists because of its similarities to the “wonder material” graphene—another form of carbon that is highly valued by industry whose research was even awarded the Nobel Prize in Physics in 2010. However, despite decades of work and theorizing, only a few fragments have ever been created before now.

This research, announced last week in Nature Synthesis, fills a longstanding gap in carbon material science, potentially opening brand-new possibilities for electronics, optics and semiconducting material research.

“The whole audience, the whole field, is really excited that this long-standing problem, or this imaginary material, is finally getting realized,” said Yiming Hu, lead author on the paper and 2022 doctoral graduate in chemistry.

Scientists have long been interested in the construction of new or novel carbon allotropes, or forms of carbon, because of carbon’s usefulness to industry, as well as its versatility.

There are different ways carbon allotropes can be constructed depending on how sp2, sp3 and sp hybridized carbon (or the different ways carbon atoms can bind to other elements), and their corresponding bonds, are utilized. The most well-known carbon allotropes are graphite (used in tools like pencils and batteries) and diamonds, which are created out of sp2 carbon and sp3 carbon, respectively.

Using traditional chemistry methods, scientists have successfully created various allotropes over the years, including fullerene (whose discovery won the Nobel Prize in Chemistry in 1996) and graphene.

However, these methods don’t allow for the different types of carbon to be synthesized together in any sort of large capacity, like what’s required for graphyne, which has left the theorized material—speculated to have unique electron conducting, mechanical and optical properties—to remain that: a theory.

But it was also that need for the nontraditional that led those in the field to reach out to Wei Zhang’s lab group.

Zhang, a professor of chemistry at CU Boulder, studies reversible chemistry, which is chemistry that allows bonds to self-correct, allowing for the creation of novel ordered structures, or lattices, such as synthetic DNA-like polymers.

After being approached, Zhang and his lab group decided to give it a try.

Creating graphyne is a “really old, long-standing question, but since the synthetic tools were limited, the interest went down,” Hu, who was a Ph.D. student in Zhang’s lab group, commented. “We brought out the problem again and used a new tool to solve an old problem that is really important.”

Using a process called alkyne metathesis—which is an organic reaction that entails the redistribution, or cutting and reforming, of alkyne chemical bonds (a type of hydrocarbon with at least one carbon-carbon triple covalent bond)—as well as thermodynamics and kinetic control, the group was able to successfully create what had never been created before: A material that could rival the conductivity of graphene but with control.

“There’s a pretty big difference (between graphene and graphyne) but in a good way,” said Zhang. “This could be the next generation wonder material. That’s why people are very excited.”

While the material has been successfully created, the team still wants to look into the particular details of it, including how to create the material on a large scale and how it can be manipulated.

“We are really trying to explore this novel material from multiple dimensions, both experimentally and theoretically, from atomic-level to real devices,” Zhang said of next steps.

Graphyne, sister material to graphene, created in bulk for the first time

These efforts, in turn, should aid in figuring out how the material’s electron-conducting and optical properties can be used for industry applications like lithium-ion batteries.

“We hope in the future we can lower the costs and simplify the reaction procedure, and then, hopefully, people can really benefit from our research,” said Hu.

For Zhang, this never could have been accomplished without the support of an interdisciplinary team, adding: “Without the support from the physics department, without some support from colleagues, this work probably couldn’t be done.”

Tesla battery research group unveils paper on new high-energy-density battery that could last 100 years

Tesla’s advanced battery research group in Canada in partnership with Dalhousie University has released a new paper on a new nickel-based battery that could last 100 years while still favorably comparing to LFP cells on charging and energy density.

Back in 2016, Tesla established its “Tesla Advanced Battery Research” in Canada through a partnership with Jeff Dahn’s battery lab at Dalhousie University in Halifax, Canada.

Dahn is considered a pioneer in Li-ion battery cells. He has been working on the Li-ion batteries pretty much since they were invented. He is credited for helping to increase the life cycle of the cells, which helped their commercialization.

His work now focuses mainly on a potential increase in energy density and durability, while also decreasing the cost.

The group has already produced quite a few patents and papers on batteries for Tesla. The automaker recently extended its contract with the group through 2026 as it added two new leaders to be mentored by Dahn.

One of those new leaders, Michael Metzger, along with Dahn himself, and a handful of PhDs in the program, are named as authors of a new research paper called “Li[Ni_0.5Mn_0.3Co_0.2]O₂ as a Superior Alternative to LiFePO₄ for Long-Lived Low Voltage Li-Ion Cells” in the Journal of the Electrochemical Society.

The paper describes a nickel-based battery chemistry meant to compete with LFP battery cells on longevity while retaining the properties that people like in nickel-based batteries, like higher energy density, which enables longer range with fewer batteries for electric vehicles.

The group wrote in the paper’s abstract:

Single crystal Li[Ni_0.5Mn_0.3Co_0.2]O₂//graphite (NMC532) pouch cells with only sufficient graphite for operation to 3.80 V (rather than ≥4.2 V) were cycled with charging to either 3.65 V or 3.80 V to facilitate comparison with LiFePO₄//graphite (LFP) pouch cells on the grounds of similar maximum charging potential and similar negative electrode utilization. The NMC532 cells, when constructed with only sufficient graphite to be charged to 3.80 V, have an energy density that exceeds that of the LFP cells and a cycle-life that greatly exceeds that of the LFP cells at 40 °C, 55 °C and 70 °C. Excellent lifetime at high temperature is demonstrated with electrolytes that contain lithium bis(fluorosulfonyl)imide (LiFSI) salt, well beyond those provided by conventional LiPF₆ electrolytes. 

The cells showed an impressive capacity retention over a high number of cycles:

The research group even noted that the new cell described in the paper could last a 100 years if the temperature is controlled at 25C:

Ultra-high precision coulometry and electrochemical impedance spectroscopy are used to complement cycling results and investigate the reasons for the improved performance of the NMC cells. NMC cells, particularly those balanced and charged to 3.8 V, show better coulombic efficiency, less capacity fade and higher energy density compared to LFP cells and are projected to yield lifetimes approaching a century at 25 °C.

One of the keys appears to be using an electrolyte with LiFSI lithium salts, and the paper notes that the benefits could also apply to other nickel-based chemistries, including those with no or low cobalt.

** Contributed from Fred Lambert, at Electrek