Scorched hair makes supercapacitors greener – EES article in Chemistry World

Researchers in China have used human hair to make a vital component of energy-storage devices. The discovery could lead to more efficient and environmentally-friendly replacements for traditional batteries.

Many batteries currently in use, such as the lead–acid batteries in cars, are heavy and bulky and rely on hazardous chemicals to store electrical charge. With increasing worldwide sales of mobile electronics, the environmental impact of batteries is receiving more attention and motivating research into supercapacitors, which can be made from sustainable carbon-based materials.

Unfortunately, these carbon materials are usually either difficult to manufacture or derived from fossil fuels. Now, however, Feng Yan and his team at Soochow University have used a simple carbonisation process to turn human hair – a common and renewable waste product – into carbon flakes suitable for use in supercapacitor electrodes.

Interested to know more? Read the full news article by Stephan McCarthy in Chemistry World here…

Read the article by Wenjing Qian et al. in EES:

Human Hair-Derived Carbon Flakes for Electrochemical Supercapacitors
Wenjing Qian, fFengxia Sun, Yanhui Xu, Lihua Qiu, Chang-Hai Liu, Sui-Dong Wang and Feng Yan
Energy Environ. Sci., 2013, Accepted Manuscript
DOI: 10.1039/C3EE43111H, Paper

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This week’s HOT articles

Take a look at this week’s selection! These articles are available free for a limited time: Graphical abstract: Transparent paper: fabrications, properties, and device applications

Transparent paper: fabrications, properties, and device applications
Hongli Zhu, Zhiqiang Fang, Colin Preston, Yuanyuan Li and Liangbing Hu
DOI: 10.1039/C3EE43024C, Minireview

Stretching and conformal bonding of organic solar cells to hemispherical surfaces
Timothy F. O’Connor, Aliaksandr V. Zaretski, Bijan A. Shiravi, Suchol Savagatrup, Adam D. Printz, Mare Ivana Diaz and Darren J. Lipomi
DOI: 10.1039/C3EE42898B, Paper

Robust production of purified H2 in a stable, self-regulating, and continuously operating solar fuel generator
Miguel A. Modestino, Karl A. Walczak, Alan Berger, Christopher M. Evans, Sophia Haussener, Carl Koval, John S. Newman, Joel W. Ager and Rachel A. Segalman
DOI: 10.1039/C3EE43214A, Communication

Physics and chemistry of CdTe/CdS thin film heterojunction photovoltaic devices: fundamental and critical aspects
S. Girish Kumar and K. S. R. Koteswara Rao
DOI: 10.1039/C3EE41981A, Review Article

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High capacity electrochemical supercapacitors derived from human hair

Aled is a guest web-writer for EES. Aled is a PhD student working on new carbon-based porous materials for the Li-ion battery. He is currently based in Liverpool, but will be moving to Singapore for two years from April 2014. Outside of science, his interests include politics, sustainability and international development.

Researchers from China have demonstrated a simple method to fabricate high-capacity electrode materials from an abundant and low-cost precursor: human hair. The materials display impressive capacitance values of up to 340 Fg-1 – beating commercial devices by a significant margin.

Developing high-performance and low-cost energy storage systems is a key goal in renewable energy research; such devices are required for numerous green-technologies such as electric vehicles and smart grids. In comparison to batteries, supercapacitors have, at the expense of energy density, relatively high power densities, short charging times and long cycle lives. A key goal of supercapacitor research has therefore been to enhance the energy density whilst maintaining these merits, and at the same time minimising cost.

In their recent article, researchers from Soochow University, China, have demonstrated a simple method whereby porous carbon materials can be prepared by high-temperature treatment of an abundant and renewable resource – human hair. When employed as supercapacitor electrodes, the materials displayed excellent performance, with energy densities up to 340 Fg-1 and negligible capacity loss even after 20,000 charge-discharge cycles.

The authors attributed the enhanced performance to the high surface area and porosity of the materials, along with the naturally high abundance of nitrogen and sulphur found in human hair, which dope the resulting carbon after heat-treatment. So will this be the future of energy storage, or is it just a hair-brained idea?

Find out for yourself, read the full article here:

Human Hair-Derived Carbon Flakes for Electrochemical Supercapacitors
Wenjing Qian, Fengxia Sun, Yanhui Xu, Lihua Qiu, Changhai Liu, Suidong Wang, and Feng Yan
Energy Environ. Sci. 2013, Accepted Manuscript
DOI: 10.1039/C3EE43111H, Paper

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Take a look at this week’s selection! This article is available free for a limited time: Graphical abstract: Constructing ionic highway in alkaline polymer electrolytes

Constructing ionic highway in alkaline polymer electrolytes
Jing Pan, Chen Chen, Yao Li, Lei Wang, Lisheng Tan, Guangwei Li, Xun Tang, Li Xiao, Juntao Lu and Lin Zhuang
DOI: 10.1039/C3EE43275K, Paper

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From seaweed to solar cells – EES article in Chemistry World

After years of using platinum, scientists suggest they could one day use extracts from marine plants to replace it in solar cells.

Dye-sensitized solar cells (DSCs) are quickly becoming a widespread and affordable alternative to photovoltaic solar cells. With this change of direction, it is pertinent that DSCs are made to be as efficient and inexpensive as possible for the mass market.

Platinum is traditionally used as the electrode material in DSCs, which, although it shows impressive performance, is not environmentally friendly and has high production costs.

Now, Tingli Ma and co-workers based in China, Japan and Switzerland have expanded their research on natural dyes and biomass manipulation to see if sea tangle, a common marine plant, is a suitable source of raw materials for DSCs. And their results look promising. The naturally sourced materials improve on the power conversion efficiency of previously tested natural dyes to the point where they are comparable to those of synthetic, more expensive materials.

Interested to know more? Read the full news article by Jessica Brand in Chemistry World here…

Read the article by Liang Wang et al. in EES:

From Marine Plant to Photovoltaic Devices
Liang Wang, Yantao Shi, Xiaogong Bai, Yujin Xing, Hong Zhang, lin Wang, Wei Guo, Ning Wang, Ting Li Ma and Michael Gratzel
Energy Environ. Sci., 2013, Accepted Manuscript
DOI: 10.1039/C3EE42767F, Communication

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EES Issue 12 of 2013 out now!

The latest issue of EES is now online. You can read the full issue here.

The outside front cover features the paper Simulations of the irradiation and temperature dependence of the efficiency of tandem photoelectrochemical water-splitting systems by Sophia Haussener, Shu Hu, Chengxiang Xiang, Adam Z. Weber and Nathan S. Lewis.

Facile synthesis of mesoporous Ni 0.3Co 2.7O 4 hierarchical structures for high-performance supercapacitors is the paper highlighted on the inside front cover by Hao Bin Wu, Huan Pang and Xiong Wen (David) Lou.

Issue 11 contains a number of excellent Opinion, Analysis, Review and Perspective articles:

Survival of the fattest
Peter R. Mooij, Gerben R. Stouten, Jelmer Tamis, Mark C. M. van Loosdrecht and Robbert Kleerebezem

Towards 15% energy conversion efficiency: a systematic study of the solution-processed organic tandem solar cells based on commercially available materials
Ning Li, Derya Baran, Karen Forberich, Florian Machui, Tayebeh Ameri, Mathieu Turbiez, Miguel Carrasco-Orozco, Martin Drees, Antonio Facchetti, Frederik C. Krebs and Christoph J. Brabec

The identification, characterization and mitigation of defect states in organic photovoltaic devices: a review and outlook
John A. Carr and Sumit Chaudhary

Metal free sensitizer and catalyst for dye sensitized solar cells
Shahzada Ahmad, Elena Guillén, Ladislav Kavan, Michael Grätzel and Mohammad K. Nazeeruddin

Retrieving and converting energy from polymers: deployable technologies and emerging concepts
Bilge Baytekin, H. Tarik Baytekin and Bartosz A. Grzybowski

Graphene-based nanocomposites: preparation, functionalization, and energy and environmental applications
Haixin Chang and Hongkai Wu

Exceeding the Shockley–Queisser limit in solar energy conversion
Cory A. Nelson, Nicholas R. Monahan and X.-Y. Zhu

Stimulus-responsive graphene systems towards actuator applications
Yang Zhao, Long Song, Zhipan Zhang and Liangti Qu

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This week’s HOT articles

Take a look at this week’s selection! These articles are available free for a limited time: Graphical abstract: N-doped graphene film-confined nickel nanoparticles as a highly efficient three-dimensional oxygen evolution electrocatalyst

N-doped graphene film-confined nickel nanoparticles as a highly efficient three-dimensional oxygen evolution electrocatalyst
Sheng Chen, Jingjing Duan, Jingrun Ran, Mietek Jaroniec and Shi Zhang Qiao
DOI: 10.1039/C3EE42383B, Paper

Structure–property relationships of oligothiophene–isoindigo polymers for efficient bulk-heterojunction solar cells
Zaifei Ma, Wenjun Sun, Scott Himmelberger, Koen Vandewal, Zheng Tang, Jonas Bergqvist, Alberto Salleo, Jens Wenzel Andreasen, Olle Inganäs, Mats R. Andersson, Christian Müller, Fengling Zhang and Ergang Wang
DOI: 10.1039/C3EE42989J, Paper

Vertically aligned BaTiO3 nanowire arrays for energy harvesting
Aneesh Koka, Zhi Zhou and Henry A. Sodano
DOI: 10.1039/C3EE42540A, Communication

Piezoelectric and ferroelectric materials and structures for energy harvesting applications
C. R. Bowen, H. A. Kim, P. M. Weaver and S. Dunn
DOI: 10.1039/C3EE42454E, Review Article

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Professor Thomas Jaramillo wins 2013 EES Readers’ Choice Award and Lectureship

Professor Thomas JaramilloWe are delighted to announce that Professor Thomas Jaramillo been selected by the EES Editorial Board as the winner of the 2014 “Energy & Environmental Science Readers’ Choice Award and Lectureship” for his article “New insights into the electrochemical reduction of carbon dioxide on metallic copper surfaces“.

Based at Stanford University in the USA, Prof. Jaramillo’s research focuses on chemical transformations in energy. Specifically, his group studies the chemistry and physics of materials as they relate to catalyzing chemical reactions of interest, namely those that convert water and CO2 into fuels and chemicals utilizing renewable energy (e.g. solar or wind), and those that convert those fuels back into usable energy in the form of electricity.

Prof. Jaramillio will give his award lecture at the upcoming  2nd International Conference on Clean Energy Science (ICCES2) taking place in Qingdao, China from 13-16 April 2014. Please do consider joining us for this exciting event.

Read Prof. Jaramillo’s award winning research today:

New insights into the electrochemical reduction of carbon dioxide on metallic copper surfaces
Kendra P. Kuhl, Etosha R. Cave, David N. Abramc and Thomas F. Jaramillo
Energy Environ. Sci., 2012, 5, 7050-7059
DOI: 10.1039/C2EE21234J

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Big data approach to solar cells – EES article in Chemistry World

After 150 million theoretical calculations, scientists at Harvard University in the US reveal results that could cut down the time and cost of experimental tests to find better organic electronic materials for solar cells.

Most solar cells are made from expensive inorganic materials. Solar cells from organic materials are a cheaper alternative and scientists have been working to find designs that are as efficient as their inorganic counterparts. However, new organic solar cell materials must be built and tested before scientists can decide whether the idea is an improvement.

The Harvard Clean Energy Project (CEP) team led by Alán Aspuru-Guzik is using the predictive power of computers to speed up this process. Analogous to the modern drug discovery process, where large numbers of molecules can be virtually screened taking only the most biologically active ones forward into development and trials, Aspuru-Guzik’s group screened 2.3 million molecular structures to find ones that had the best properties for solar cells.

Interested to know more? Read the full news article by Rowan Frame in Chemistry World here…

Read the article by  J Hachmann et al. in EES:

Lead candidates for high-performance organic photovoltaics from high-throughput quantum chemistry – the Harvard Clean Energy Project
Stuart Licht, Baochen Cui, Jessica Stuart, Baohui Wang and Jason Lau
Energy Environ. Sci., 2013, Advance Article
DOI: 10.1039/C3EE42654H, Paper

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Improving solar cell efficiency by optical design

Table of contents imageScientists in the United States have designed a Cu2ZnSn(S, Se)4 (CZTSSe) solar cell with the greatest efficiency to date using an optical-design approach.

The researchers describe a new optical architecture for CZTSSe photovoltaic devices that improves the record power-conversion efficiency for this technology from 11.1 per cent to 12.0 per cent. CZTSSe absorbers are appealing for terawatt-scale thin-film solar deployment because they are composed of earth-abundant, non-toxic metals.

Using analytical modelling, verified by experiments, the team identified the optimal optical design for increasing the amount of light absorbed in the CZTSSe layer. The new design uses thinner CdS and transparent-conducting layers that lie atop the CZTSSe absorber.

The researchers also showed that that the approach typically used for solar-cell photon management – that is minimising the number of photons reflected from the solar cell surface – does not maximise current for this type of device.

Read the full details of this article in Energy & Environmental Science:

Optical designs that improve the efficiency of Cu2ZnSn(S,Se)4 solar cells
Mark T. Winkler, Wei Wang, Oki Gunawan, Harold J. Hovel, Teodor K. Todorov and David B. Mitzi
DOI: 10.1039/C3EE42541J

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