Archive for the ‘Materials’ Category

Improving Sodium-Ion Batteries for Large-Scale Energy Storage

One of the greatest global challenges is the ever-growing demand for reliable, large-scale energy production.

The depletion of cost-effective fossil fuels and concerns about climate change are driving the need for clean energy sources derived from renewable technologies. Wind and solar power show significant potential as sustainable alternatives however, both solar photovoltaics and wind energy display intermittent output which has led to concerns regarding reliability for global energy production. As a result, there has been an increased demand for the development of large-scale energy storage.

Among energy storage technologies, lithium-ion batteries (LIBs) predominate however lithium’s high cost, abundance, unevenglobal distribution and safety concerns have limited its widespread application. In recent years, researchers have become interested in high energy sodium-ion batteries (SIBs) as a safer and less expensive alternative. Nevertheless, their inferior electrochemical performances, due to the larger size and heavier mass of sodium ions, has become a major hurdle in the development and implementation of SIBs.

In a recent ChemComm publication, Prof. Jun Chen of Nankai University has demonstrated the improved capabilities of SIBs using a manganite hydroxide (MnOOH)-based anode.

In the past, transition metal oxides, such as MnOx-based materials, have been used in LIBs as they possess a high theoretical capacity and—in some cases—improved conductivity. In this study by Chen and co-workers, MnOOH nanorods (figure, top) were synthesized, and were shown to display a higher initial Coulombic efficiency and rate performance compared to MnO2 (a common anode material in LIBs). Cyclic voltammetry (figure, bottom) and various other spectroscopic techniques were used to investigate the electrochemical properties and storage behaviour of MnOOH-SIBs. These experiments showed improvements in charge capacity and overall rate performance when compared to other transition metal oxides and sulfides.

The results of this work show promise toward the fabrication of high-performance SIBs which are encouraging alternatives for energy storage due to sustainable cost, improved thermal stability and transport safety. The performance of SIBs still lags behind that of LIBs but this study, among others, demonstrates that new electrode materials need to be explored in the development of SIBs and solving large-scale energy storage challenges.

To find out more see:

MnOOH nanorods as high-performance anodes for sodium ion batteries
Lianyi Shao, Qing Zhao and Jun Chen
DOI: 10.1039/C7CC00087A


Victoria Corless is currently completing her Ph.D. in organic chemistry with Prof. Andrei Yudin at The University of Toronto. Her research is centred on the synthesis of kinetically amphoteric molecules, which offer a versatile platform for the development of chemoselective transformations with particular emphasis on creating novel biologically active molecules.

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Soft drinks power origami cell

Graphical Abstract

Source: © Royal Society of Chemistry - The tiny fuel cell is made from a folded sheet of filter paper that holds the anode and cathode

Miniature fuel cell made from folded filter paper runs on sugary drinks.

Researchers in China have found a way to integrate the ancient Japanese art of paper folding, origami, into a miniature biofuel cell that can generate energy from soft drinks.

Biofuel cells use enzymes, instead of precious metals, as catalysts to oxidise their fuel. Miniature versions have excited researchers because they are portable and have high efficiency. They could provide power for implants or electronic contact lenses or harvest energy from perspiration. However, designing these small biofuel cells is difficult due to complicated assembly and high costs.


Read the full article in Chemistry World >>>


A miniature origami biofuel cell based on a consumed cathode
You Yu, Yujie Han, Baohua Lou, Lingling Zhang, Lei Hana and Shaojun Dong
Chem. Commun., 2016, 52, 13499-13502
DOI: 10.1039/C6CC07466A, Communication

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Incorporating DNA hydrogels into enzymatic biofuel cells

I remember a time when mobile phones weren’t so power hungry, and when my phone could go a week on one charge. Admittedly, that was before it had a colour screen, internet connectivity and a hundred other bells and whistles. Increased device connectivity, in particular, has led to a huge increase in power demands and the need for better battery technology.

Wouldn’t it be marvellous if your phone battery generated its power from a wide selection of renewable sources? Khiem Van Nguyen and Shelly Minteer from the University of Utah look toward this possibility in their most recent ChemComm, which describes the use of DNA hydrogels in the production of an enzymatic biofuel cell.

The authors describe how they used the self-assembly of DNA monomers under physiological conditions to form a DNA hydrogel capable of trapping glucose oxidase, the most widely used enzyme in enzymatic biofuel cells. This DNA hydrogel remains permeable to small molecules, such as the battery fuel, whilst successfully trapping the enzyme close to the electrode surface.  Enzyme immobilization on the electrode surface is critical to achieve an effective enzymatic biofuel cell, and this model biobattery was shown to have a similar performance to previously reportedglucose oxidase biofuel cells.

Entrapment of glucose oxidase in DNA hydrogel

With enzymes capable of oxidising a wide range of fuels, from alcohols and carbohydrates to amino acids, it may not be too long until a multi-enzyme biobattery is created that can be powered by the sweat from your skin. Then you’ll be able to browse the internet wherever and whenever you want…provided you have signal, of course.

To read the details, check out the ChemComm article in full:
Investigating DNA hydrogels as a new biomaterial for enzyme immobilization in biobatteries
Khiem Van Nguyen and Shelley D Minteer
Chem. Commun., 2015, 51, Advance Article
DOI: 10.1039/C5CC04810A

For example: S. Aquino Neto et al., Power Sources, 2015, 285, 493–498

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Hotter and hotter: increasing the potential of gold nanostars

Gold nanostars are gold nanoparticles with multiple branches, a shape which gives rise to their unique properties. These nanoparticles have tuneable localized surface plasmon resonances in the biologically transparent near-IR window, and excitation of these plasmons using a laser creates a local temperature  increase. For this reason, gold nanostars have potential for use in non-invasive antitumoral and antibiofilm laser treatments.

The problem faced by scientists, however, is how to achieve a temperature increase that is large enough to be effective, without exposing the overlying skin to a level of irradiation that exceeds the safe limits. This is what Piersandro Pallavicini from the Department of Chemistry at the University of Pavia, and an international team of colleagues, set out to investigate.

They generated gold nanostars with plasmon resonances at 835 and 1530 nm, respectively. Each of these plasmons could be irradiated separately, leading to observable increases in temperature. However, when both plasmons were irradiated simultaneously, the temperature increase was equal to the sum of the temperature increases when the plasmons were irradiated separately.

Temperature increases observed from the laser excitation of individual or multiple plasmon resonances of gold nanostars

The implication of these findings is that Pallavicini and colleagues successfully found a way to obtain a larger local temperature increase using irradiation that remains below the safe limits. This significantly increases the potential of gold nanostars for application in the in the treatment of biofilm growth on implants in vivo.

To find out the full details of the additive temperature effect, read the ChemComm article today – it’s free to access until 21st October 2015:

Monolayers of gold nanostars with two near-IR LSPRs capable of additive photothermal response
Piersandro Pallavicini, Simone Basile, Giuseppe Chirico, Giacomo Dacarro, Laura D’Alfonso, Alice Dona, Maddalena Patrini, Andrea Falqui, Laura Sironi and Angelo Taglietti
Chem. Commun., 2015, 51, 12928-12930
DOI: 10.1039/C5CC04144A

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Hierarchical 3D immunoassays – higher loading, lower fouling

If you are producing an immunoassay there are two key parameters you need to understand and optimise: surface structure and surface chemistry. Get these two parameters right and you will optimise the sensitivity of your immunoassay. 

Although there have been a multitude of 3D surface generation routes reported, they are generally complicated and require a lot of additional steps. Although these 3D surfaces lead to high probe loading levels they also often lead to high levels of non-specific protein absorption, undoing any good the surface structure would have led to. 

Jinghua Yin and team from the State Key Laboratory of Polymer Physics and Chemistry at the Changchun Institute of Applied Chemistry have focussed on both properties to generate a much improved immunoassay. 

 Firstly they generated a 3D surface using UV irradiation of polystyrene spheres onto a substrate; they then grafted polymer brushes to the sphere surface. The polymer brushes not only further increased the surface area (more than doubling it from the bare sphere surface) but also acted as an anti-fouling agent, reducing the amount of non-specific binding observed by up to 90%. 

Antibody loading on different surface types showing increasing loading levels

 

The commonality of the functional groups on the polymer brushes mean that any antibody can be attached to the prepared surface. To find out the details of how to make these surfaces and try them out on your own immunoassays, read the paper today!


To read the details, check out the ChemComm article in full:
Facile fabrication of microsphere-polymer brush hierarchically three-dimensional (3D) substrates for immunoassays
Jiao Ma, Shifang Luan, Lingjie Song, Shuaishuai Yuan, Shunjie Yan, Jing Jin and Jinghua Yin
Chem. Commun., 2015, 51, 6749-6752
DOI: 10.1039/C5CC01250C

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Rotaxane Pulley – To Me, To You

Mechanically interlocked molecules have received ever increasing focus over the last number of years due to their potential to mimic the function of macroscopic devices in the molecular world.

Examples include molecular elevators and molecular muscles and with this Communication Zheng Meng and Chuan-Feng Chen of the CAS Key Laboratory of Molecular Recognition and Function at the Chinese Academy of Sciences in Beijing have added pulley-like shuttling motion to the toolkit.

Molecular pulley system powered by acid and base

Molecular pulley system powered by acid and base

Using their previously reported* triptycene-derived crown ether host and combining it with a linear guest with three dibenzylammonium and three N-methyltriazolium sites, they have made a molecular pulley system that mimics the plain rotary motion and linear translocation of full sized pulleys. The movement is powered by acid or base leading to one end of the cable-like guest moving towards the host while the other moves away (picture).

The researchers have not only added to the toolbox of molecular motion components but also provided new insights towards further developing molecular machines.

If you want to make your own molecular pulley read the article today! 

To read the details, check out the ChemComm article in full – it’s free to access until 10th May:
A molecular pulley based on a triply interlocked [2]rotaxane
Zheng Meng and Chuan-Feng Chen
Chem. Commun., 2015, 51, Advance Article
DOI: 10.1039/C5CC01301A


*(a) C. F. Chen, Chem. Commun., 2011, 47, 1674–1688 RSC; (b) Y. Han, Z. Meng, Y. X. Ma and C. F. Chen, Acc. Chem. Res., 2014, 47, 2026–2040

**Access is free through a registered RSC account – click here to register

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Opening the door to poly(ionic liquid)s with enhanced properties

Poly(ionic liquid)s, or PILs, are polyelectrolytes whose potential uses are being investigated for a variety of technologies, such as batteries, membranes, solar cells and switchable surfaces. In this ChemComm communication, Professor Eric Drockenmuller and co-workers at the Université de Lyon, University of Liège and the Institut Universitaire de France describe a new family of PILs based on poly(vinyl ester 1,2,3-triazolium)s, which should give rise to new properties and application possibilities. 

The materials are prepared from a multistep route making use of `click chemistry´(copper(I) catalysed azide alkyne Huisgen cycloaddition reaction), palladium catalyzed vinyl group exchange, and cobalt mediated radical polymerisation. This route yields a neutral polymer, which is transformed into the poly(ionic liquid) using N-methyl bis[(trifluoromethyl)sulfonyl]imide. This useful reagent alkylates the triazole group present, and delivers the bis[(trifluoromethyl)sulfonyl]imide counterion in one step. 

Synthetic route used to yield new poly(vinyl-ester 1,2,3-triazolium)s

The ionic conductivity for the PIL reported is slightly lower than for other types of PIL. To tune this property, a variety of alkynes and azides are being tested in the ring forming step of the reaction, which will result in different substituents on the triazolium ring and on the spacer group between the polymer backbone and triazolium ring.  Changes in thermal properties in the the neutral precursor-to-PIL stage of the reaction were measured using broadband dielectric spectroscopy. Significant changes in solubility, and a 9⁰C rise in glass transition temperature to -16⁰C, were observed. 

The molecular variety introduced by this new synthetic approach offers large scope for fine tuning the electronic and mechanical material properties of these polyelectrolytes, further enabling their use in important technological applications. 

Read this Chemical Communication today – it’s free to access until 3rd April*: 

Poly(vinyl ester 1,2,3-triazolium)s: a new member of the poly(ionic liquid)s family
M. M. Obadia, G. Colliat-Dangus, A. Debuigne, A. Serghei, C. Detrembleurb and E. Drockenmuller
DOI: 10.1039/c4cc08847f 

*Access is free through a registered RSC account – click here to register

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Biochemical Logic Systems – closed-loop “Sense/Act” operations

When research in a particular area reaches saturation point, the question of future applications becomes critically important. This recent Feature Article in ChemComm considers molecular logic gates, which have not yet achieved pure computational applications (with their hoped for advantages) due to limitations caused by noise build-up and cross-talk between various biomolecular elements. Thus they are unable to compete with electronic computing devices. The authors ask the question: what potential applications are there that justify the continued research in this field?

Evgeny Katz from the Department of Chemistry and Biomolecular Science at Clarkson University with Sergiy Minko from the Nanostructured Materials Lab at the University of Georgia lead the reader through a short overview of potential answers. These include “smart” switchable membranes, electrodes, biofuel cells and drug-releasing systems.
 
The use of biochemical data processing to produce a yes/no answer provides the opportunity for direct coupling with signal-responsive materials to produce a closed-loop “sense/act” operation. This ability has the potential to transform the field of biosensors and bioactuators.

(A) A biocatalytic cascade activated by enzyme–substrate inputs and resulting in the in situ produced pH changes. (B) The logic circuitry equivalent to the biocatalytic cascade. (C) pH-switchable electrode interface modified with a polymeric brush.

The authors could be considered brave to ask the question of such a popular focus of research, but this article provides an opportunity for reflection and thought about what biochemical computing research can uniquely achieve. Having read this article I was left with a sense of excitement at the specific in vivo sensing possibilities that biochemical computing provides. To find out if you think the opportunities are exciting too, read the article today!

To read the details, check out the ChemComm article in full:
Enzyme-based logic systems interfaced with signal-responsive materials and electrodes
Evgeny Katz and Sergiy Minko
Chem. Commun., 2015, 51, Advance Article
DOI: 10.1039/C4CC09851J

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Capturing C60 in a Crystalline Copolymer Chain

Since its structural realisation in 1985, C60 has garnered much attention in the chemical world for not only its spherical shape, but also its stability, electronic properties and the ability to do chemistry on its surface.

One such avenue that has proven popular in recent times is the incorporation of C60 into one-, two- and three-dimensional arrays, either covalently or non-covalently, in attempts to control the distribution of the molecules in the solid- or solution-phase.  One problem that arises in the synthesis of these extended frameworks, however, is that there often a large amount of disorder and void space in the structure, so it can be difficult to ascertain with much degree of certainty how these C60 molecules are oriented. This uncertainty can consequentially result in the properties and behaviours of the new materials remaining unidentified.

Now, researchers from the University of California, DavisMarilyn Olmstead and Alan Balch – have shown that coordination chemistry can be used to not only generate polymers that covalently link molecules of functionalised C60 in such a manner that can they can be studied crystallographically, but also that these polymers can be used to capture free C60 and C70.

Initially, polymers of C60 were synthesised through the mono-functionalisation of C60 with a piperazyl group, which, on account of its two tertiary amines, can coordinate in a linear fashion with transition metal ions, in this case rhodium(II) acetate. Upon the combination of these two components, a linear one-dimensional polymer was formed, in which it could be seen crystallographically that the C60 moieties were positioned on alternating sides of the polymer chain. These polymer chains were further found to extend into two dimensions through the interdigitation of neighbouring chains in a zipper-like fashion. C60-Rh(II) polymers can capture free C60

Perhaps more interestingly is that when these polymer chains were synthesised in the presence of either C60 or C70, free molecules of C60 or C70 were seen to occupy the void spaces between the C60 molecules of the polymer. Additionally, if a mixture of C60 and C70 was present in the polymer synthesis, it was observed that only C60 was captured by the polymer, most likely as a result of a better geometric match between the polymer and the spherical C60 in preference to the more elongated shape of C70.

This work elegantly demonstrates the generation of not only a self-assembling C60-containing polymer that can be characterised structurally in the solid state, but of one  that can entrap free molecules of C60 selectively over molecules of C70. Based on the properties of free C60 and transition metal complexes, the electronic and chromophoric properties of such a crystalline system could also be expected to offer some noteworthy results.

Read this HOT ChemComm article in full!

Zipping up fullerenes into polymers using rhodium(II) acetate dimer and N(CH2CH2)2NC60 as building blocks
Amineh Aghabali, Marilyn M. Olmstead and Alan L. Balch
Chem. Commun., 2014, Advance Article.
DOI: 10.1039/C4CC06995A

Biography

Anthea Blackburn is a guest web writer for Chemical Communications. Anthea is a graduate student hailing from New Zealand, studying at Northwestern University in the US under the tutelage of Prof. Fraser Stoddart (a Scot), where she is exploiting supramolecular chemistry to develop multidimensional systems and study the emergent properties that arise in these superstructures. When time and money allow, she is ambitiously attempting to visit all 50 US states before graduation.

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Bubble power: Driving self-propelled machines with acetylene bubbles

Self-propelled micro/nanomachines were once the thing of science-fiction, but as so often is the case, fiction has become reality in recent years. Such devices could in the future find uses in environmental remediation and biomedical applications. Researchers around the world have been making progress on designing these machines, and it is a novel fuel-free autonomous self-propelled motor which is the focus of this Chemical Communication by Martin Pumera and team from the School of Physical and Mathematical Sciences at Nanyang Technological University.

Rather than focus on oxygen bubble propulsion, which often requires the use of high levels of toxic hydrogen peroxide, they have developed an acetylene bubble based motor. To achieve this they utilised the reaction of water and calcium carbide, which produces acetylene and calcium hydroxide. This approach makes use of the water that will be found in the most common application environments, but does not require reactive metals such as magnesium and aluminium. The work expands the scope of bubble-propulsion beyond hydrogen and oxygen and gives designers of micro/nanomachines greater power unit choices in their designs.

Acetylene bubble powered motor in water.

The most important part of the research reported in this Communication is the optimisation of an encapsulation layer around the calcium carbide to control the reaction. However, to find out what this layer is made of and how to prepare it you will have to read the article today.

To read the details, check out the Chem Comm article in full:

Acetylene bubble-powered autonomous capsules: towards in situ fuel
James Guo Sheng Moo, Hong Wang and Martin Pumera
Chem. Commun., 2014, 50, Advance Article
DOI: 10.1039/C4CC07218A
   

    

    

    

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