Chemical Science Blog

Yu and coworkers from The University of Queensland, Australia have introduced an aluminum-selenium (Al-Se) battery as a new member of the rechargeable Al-ion battery family. This battery reported in Chemical Science exhibited a capacity of 178 mAh per gram of Se, high discharging voltage above 1.5 V and satisfactory lifetime.

Al-ion batteries have attracted increasing attention as next-generation energy-storage devices. They are potentially more affordable and safer than Li-ion batteries, due to the natural abundance and the existence of native oxide surface layers of aluminum, respectively. One of the major challenges hindering the wide application of Al-ion batteries is the lack of feasible cathode materials. Previously investigated cathodes have drawbacks of low charge-storage capacity, low discharging voltage, poor electrical conductivity or chemical instability.

Inspired by sulfur, Yu and coworkers selected selenium as a cathode material for Al-ion batteries. Selenium has substantially higher electrical conductivity and lower ionization potential than sulfur, which is expected to improve the energy-storage capacity of batteries. However, a major drawback of selenium is that the oxidation product generated upon charging batteries, Se₂Cl₂, can dissolve quickly in electrolytes and lead to battery failure. Solving this problem would make selenium a promising cathode for Al-ion batteries.

To resolve this issue, the authors introduced a mesoporous carbon named CMK-3, nanorods that are capable of physically adsorbing Se₂Cl₂. The cathode, composed of Se nanowires and CMK-3 nanoparticles, is thus anticipated to improve the lifespan of batteries, as any Se₂Cl₂ that is generated will be confined inside the pores of CMK-3 (Figure 1).

Figure 1. A schematic illustrating the CMK-3’s capability of trapping Se₂Cl₂. The chemical equation below shows how selenium reacts with aluminum during charge and discharge processes.

As expected, the performance of these Al-Se batteries was stable. They retained more than 80% of the initial capacity after 50 consecutive charge-discharge cycles at 100 mA/g (Figure 2a). Additionally, the discharging capacity of the batteries reached 178 mAh per gram of selenium at 100 mA/g, and the discharging potential was above 1.5 V (Figure 2b).

Figure 2. (a) The specific capacity of the Al-Se batteries of each cycle at different current densities. (b) The variation of battery potential with specific capacity of the 2nd, 5th, 10th, and 30th charge-discharge cycles.

These promising Al-Se batteries could encourage future work to continue progress into the development of affordable and durable Al-ion batteries.

To find out more please read:

Rechargeable Aluminum-Selenium Batteries with High Capacity

Xiaodan Huang, Yang Liu, Chao Liu, Jun Zhang, Owen Noonan and Chengzhong Yu

Chem. Sci., 2018, DOI: 10.1039/C8SC01054D

About the blogger:

Tianyu Liu obtained his Ph.D. (2017) in Physical Chemistry from University of California, Santa Cruz in the United States. He is passionate about scientific communication to introduce cutting-edge research to both the general public and scientists with diverse research expertise. He is a blog writer for Chem. Commun. and Chem. Sci. More information about him can be found at http://liutianyuresearch.weebly.com/.

We are happy to present a selection of our HOT articles over the past month. To see all of our HOT referee-recommended articles from 2018, please find the collection here.

As always, Chemical Science articles are free to access.

A high spatiotemporal study of somatic exocytosis with scanning electrochemical microscopy and nanoITIES electrodes
Theresa M. Welle, Kristen Alanis, Michelle L. Colombo, Jonathan V. Sweedler and Mei Shen
Chem. Sci., 2018, Advance Article
DOI: 10.1039/C8SC01131A, Edge Article

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Diffusion across a gel–gel interface – molecular-scale mobility of self-assembled ‘solid-like’ gel nanofibres in multi-component supramolecular organogels
Jorge Ruíz-Olles and David K. Smith
Chem. Sci., 2018, Advance Article
DOI: 10.1039/C8SC01071D, Edge Article

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Fine-Tuned Organic Photoredox Catalysts for Fragmentation-Alkynylation Cascades of Cyclic Oxime Ethers
Franck Le Vaillant, Marion Garreau, Stefano Nicolai, Ganna Gryn’ova, Clemence Corminboeuf and Jerome Waser
Chem. Sci., 2018, Accepted Manuscript
DOI: 10.1039/C8SC01818A, Edge Article

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A multifunctional SERS sticky note for real-time quorum sensing tracing and inactivation of bacterial biofilm
Huangxian Ju, Jingxing Guo, Ying Liu, Yunlong Chen and Jianqi Li
Chem. Sci., 2018, Accepted Manuscript
DOI: 10.1039/C8SC02078G, Edge Article

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Rapid photoinduced charge injection into covalent polyoxometalate-bodipy conjugates
Fiona A Black, Aurélie Jacquart, Georgios Toupalas, Sandra Alves, Anna Proust, Ian P Clark, Elizabeth Gibson and Guillaume Izzet
Chem. Sci., 2018, Accepted Manuscript
DOI: 10.1039/C8SC00862K, Edge Article

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Site-selective C-C modification of proteins at neutral pH using organocatalyst-mediated cross aldol ligations
Richard J Spears, Robin Brabham, Darshita Buddhadev, Tessa Keenan, Sophie McKenna, Julia Walton, James A Brannigan, Marek Brzozowski, Anthony J Wilkinson, Michael Plevin and Martin A Fascione
Chem. Sci., 2018, Accepted Manuscript
DOI: 10.1039/C8SC01617H, Edge Article

Australian scientists from The University of Adelaide and Graz University of Technology recently made a breakthrough in protein chemistry. They revealed that the key to successfully encasing proteins into metal organic frameworks (MOFs, a family of highly porous organic-metal coordination molecules) was the surface charge of the proteins. Their work was recently published in Chemical Science.

Encapsulating proteins into MOFs, a process termed “biomimetic mineralisation”, is an efficient way to protect and preserve proteins. This process is typically initiated by mixing the proteins and the precursors of a MOF. The MOF starts to grow at the protein surface and eventually fully covers the protein. As the growth of the MOF begins with nucleation on the protein surface, the surface properties play an important role in controlling the rate and quality of the encapsulation. Unfortunately, the interplay between protein surface and MOF growth has not been well understood, leading to inefficient reactions that require excess MOF precursors and long reaction times.

The authors demonstrated for the first time that the surface charge is one of the key factors that affects the possibility of biomimetic mineralisation. Specifically, they discovered that proteins with strongly negative charged surfaces, such as pepsin and bovine serum albumin, were able to be spontaneously incorporated into ZIF-8 (a benchmark MOF). Conversely, those with naturally positively charged or slightly negatively charged surfaces, including haemoglobin, were incapable of forming composites with ZIF-8. The authors further showed that changing the surface charge could allow or prohibit the encapsulation. For example, after reacting the lysine groups of haemoglobin with succinic anhydride, the surface of haemoglobin became more negative and ZIF-8 could now readily wrap around the protein (Figure 1). The surface potential threshold to induce biomimetic mineralisation was determined to be -30 mV.

Figure 1. Schematic illustrations of the biomimetic mineralisation of haemoglobin and bovine serum albumin. Haemoglobin with slightly negatively charged surface is unable to form composites with ZIF-8, but becomes active after succinylation or acetylation to make its surface strongly negatively charged. On the contrary, bovine serum albumin with a strongly negatively charged surface readily combines with ZIF-8, but loses its activity when its surface becomes less negatively charged via amination.

The mechanism of the aforementioned observations was attributed to the electrostatic attraction between the protein surface and Zn²⁺, one of the MOF precursors. The more negatively the surface is charged, the more easily the Zn²⁺ will attach to and accumulate at the protein surface. The adsorbed Zn²⁺ ions then serve as the nucleation sites for the MOF to grow around the protein. This hypothesis is proven by a number of control experiments and also validated by computational studies.

This study highlights the surface potential of a protein as a critical factor in its ability to induce biomimetic mineralisation with MOFs. The conclusions could potentially be extended to biomolecules other than proteins (e.g. viruses and cells) to facilitate their integration with various MOFs.

To find out more please read:

Protein Surface Functionalisation as A General Strategy for Facilitating Biomimetic Mineralisation of ZIF-8

Natasha K. Maddigan, Andrew Tarzia, David M. Huang, Christopher J. Sumby, Stephen G. Bell, Paolo Falcaro and Christian J. Doonan

Chem. Sci., 2018 , DOI: 10.1039/c8sc00825f

About the blogger:

Tianyu Liu obtained his Ph.D. (2017) in Physical Chemistry from University of California, Santa Cruz in United States. He is passionate about scientific communication to introduce cutting-edge research to both the general public and scientists with diverse research expertise. He is a blog writer for Chem. Commun. and Chem. Sci. More information about him can be found at http://liutianyuresearch.weebly.com/.