Tag Archives: nanocarbon

Quick and efficient nanographene synthesis

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Thank you to Nagoya University (Japan) for making this image available.

Caption: APEX reactions are carried out on the K, M and bay regions of the polycyclic aromatic hydrocarbon, synthesizing multiple nanographenes. These reactions can then be repeated, further increasing the number of potential nanographene structures that can be synthesized. Credit: Issey Takahashi

From a June 28, 2021 Nagoya University press release (also on EurekAlert),

A group of researchers at Nagoya University, Japan, have developed a new method for quickly and efficiently synthesizing nanographenes, a type of nanocarbon with great potential as a next generation material.

Nanographenes are the part structures of graphene, which is a sheet of carbon atoms around 3 nanometers thick with particular potential for use in semiconductor development, having electron mobility several hundred times better than current generation materials. Graphene was first isolated in 2004, a discovery which received the 2010 Nobel Prize in physics, making it a very new material which is currently the subject of a great deal of research.

With magnetic and electric characteristics beyond those of graphene, nanographenes are equally of interest to scientists in the nanocarbon research field. The biggest obstacle, albeit an exciting one, faced by researchers is the sheer number of potential nanographenes. The number of potentially possible nanographene structures increases with the number of benzene rings (6 atoms of carbon in a hexagonal formation) to make them. For example, even a relatively small 10 benzene ring nanographene may have up to 16,000 variants. As each nanographene has different physical characteristics, the key to applied nanographene research is to identify the relationship between the structure and characteristics of as many nanographenes as possible.

Thus, scientists’ task is to create a nanographene library, containing data on the properties of as many nanographenes as possible. However, the current method of nanographene synthesis, known as a coupling reaction, is a multi-step process which produces one single nanographene. Thus, to create a 100-nanographene library, 100 separate coupling reactions would have to be carried out. Even this would be a significant undertaking, rendering the construction of a truly comprehensive nanographene library practically impossible.

To solve this problem, the Nagoya University research group, led by Professor Kenichiro Itami, have been working on the APEX reaction, a reaction which uses polycyclic aromatic hydrocarbons as templates to synthesize nanographenes. Polycyclic aromatic hydrocarbons have three areas of their structure – known as the K region, M region and bay region – which can be elongated in an APEX reaction, producing three nanographenes. These nanographenes can then be further elongated in a second reaction, meaning that a large number of nanographenes can be synthesized from a single polycyclic aromatic hydrocarbon template molecule.

With Professor Itami’s group having already developed the K region APEX reaction, and another group of scientists having done so for the bay region, they turned their attention to the M region. They activated the M region using the 1950 Nobel Prize winning Diels-Alder reaction, and succeeded in carrying out an elongation reaction on the activated M region, thus rendering all three possible sites on the polycyclic aromatic hydrocarbons capable of synthesizing nanographenes.

The researchers were able to produce 13 nanographenes with three APEX reactions, with most of these being previously unseen structures, thus proving both the efficiency and usefulness of this new method.

This exciting new piece of research and its potential to accelerate the creation of nanographene libraries is a step towards the development of the next generation of materials, which have the potential to revolutionize semiconductors and solar energy and improve lives all around the world.

Here’s a link to and a citation for the paper,

Diversity-oriented synthesis of nanographenes enabled by dearomative annulative π-extension by Wataru Matsuoka, Hideto Ito, David Sarlah & Kenichiro Itami. Nature Communications volume 12, Article number: 3940 (2021) DOI: https://doi.org/10.1038/s41467-021-24261-y Published 24 June 2021

This paper is open access.

Anyone have a spare portabella (also known as, portobello) mushroom? I need for my phone

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Scientists as the University of California at Riverside (UCR) have developed a type of lithium-ion battery with portabella mushrooms, from a Sept. 29, 2015 news item on ScienceDaily,

Can portabella mushrooms stop cell phone batteries from degrading over time?

Researchers at the University of California, Riverside Bourns College of Engineering think so.

They have created a new type of lithium-ion battery anode using portabella mushrooms, which are inexpensive, environmentally friendly and easy to produce. The current industry standard for rechargeable lithium-ion battery anodes is synthetic graphite, which comes with a high cost of manufacturing because it requires tedious purification and preparation processes that are also harmful to the environment.

A Sept. 29, 2015 UCR news release (also on EurekAlert) by Sean Nealon, which originated the news item, expands on the theme,

With the anticipated increase in batteries needed for electric vehicles and electronics, a cheaper and sustainable source to replace graphite is needed. Using biomass, a biological material from living or recently living organisms, as a replacement for graphite, has drawn recent attention because of its high carbon content, low cost and environmental friendliness.

UC Riverside engineers were drawn to using mushrooms as a form of biomass because past research has established they are highly porous, meaning they have a lot of small spaces for liquid or air to pass through. That porosity is important for batteries because it creates more space for the storage and transfer of energy, a critical component to improving battery performance.

In addition, the high potassium salt concentration in mushrooms allows for increased electrolyte-active material over time by activating more pores, gradually increasing its capacity.

A conventional anode allows lithium to fully access most of the material during the first few cycles and capacity fades from electrode damage occurs from that point on. The mushroom carbon anode technology could, with optimization, replace graphite anodes. It also provides a binderless and current-collector free approach to anode fabrication.

“With battery materials like this, future cell phones may see an increase in run time after many uses, rather than a decrease, due to apparent activation of blind pores within the carbon architectures as the cell charges and discharges over time,” said Brennan Campbell, a graduate student in the Materials Science and Engineering program at UC Riverside.

…

Nanocarbon architectures derived from biological materials such as mushrooms can be considered a green and sustainable alternative to graphite-based anodes, said Cengiz Ozkan, a professor of mechanical engineering and materials science and engineering.

The nano-ribbon-like architectures transform upon heat treatment into an interconnected porous network architecture which is important for battery electrodes because such architectures possess a very large surface area for the storage of energy, a critical component to improving battery performance.

One of the problems with conventional carbons, such as graphite, is that they are typically prepared with chemicals such as acids and activated by bases that are not environmentally friendly, said Mihri Ozkan, a professor of electrical and computer engineering. Therefore, the UC Riverside team is focused on naturally-derived carbons, such as the skin of the caps of portabella mushrooms, for making batteries.

It is expected that nearly 900,000 tons of natural raw graphite would be needed for anode fabrication for nearly six million electric vehicle forecast to be built by 2020. This requires that the graphite be treated with harsh chemicals, including hydrofluoric and sulfuric acids, a process that creates large quantities of hazardous waste. The European Union projects this process will be unsustainable in the future.

Here’s link to and a citation for the paper,

Hierarchically Porous Carbon Anodes for Li-ion Batteries by Brennan Campbell, Robert Ionescu, Zachary Favors, Cengiz S. Ozkan, & Mihrimah Ozkan. [Nature] Scientific Reports 5, Article number: 14575 (2015)  doi:10.1038/srep14575 Published online: 29 September 2015

This is an open access paper