Highly Efficient Grid-scale Electricity Storage at Fifth of Cost

Rows of huge tanks full of chemical solutions storing energy generated from massive solar and wind farms and powering whole cities: It’s a landscape that millennials might very well equate with the new normalBatteries will power this new paradigm, and they won’t necessarily all be lithium-ion batteries. The flow battery is staking a claim in the renewable energy world of the future. Flow batteries are definiively the future of energy storage, or at least an important part of it.

What are flow batteries? They are systems of two connected tanks, both containing electrolyte liquids: one with a positively charged cathode and the other with the negatively charged anode, just like a lithium-ion battery. Electricity passes from one electrolyte liquid to the other via a membrane between the tanks.

 

Rechargeable like lithium-ion batteries, flow batteries have longer lives because the electric current flowing from tank to tank does not degrade the membrane. True flow batteries are also called redox flow batteries, after the two reactions they utilize: reduction, or a gain of electrons, and oxidation, or loss of electrons from electrolyte liquid to electrolyte liquid.

Now researchers in WMG at the University of Warwick, in collaboration with Imperial College London, have found a way to enhance hybrid flow batteries and their commercial use. The new approach can store electricity in these batteries for very long durations for about a fifth the price of current technologies, with minimal location restraints and zero emissions.

The scientists enhanced three hybrid flow cells using nitrogen doped graphene (exposed to nitrogen plasma) in a binder-free electrophoresis technique (EPD). Wind and solar power are increasingly popular sources for renewable energy. Unfortunately, intermittency issues keep them from connecting widely to the National grid. One potential solution to this problem involves in the deployment of long-duration battery technology, such as the redox flow battery. Despite its great promise the current costs of this system are a key determining factor to real-world adoption. An affordable grid battery should cost £75/kWh, according to the US Department of Energy. Lithium-ion batteries, which lead the charge for grid storage, cost about £130/kWh. The hybrid flow battery’s total chemical cost is about 1/30th the cost of competing batteries, such as lithium-ion systems. Scaled-up technologies may be used to store electricity from wind or solar power, for multiple days to entire seasons, for about £15 to £20 per kilowatt hour.

https://warwick.ac.uk/

How To Detect Heart Failure From A Single Heartbeat

Researchers have developed a neural network approach that can accurately identify congestive heart failure with 100% accuracy through analysis of just one raw electrocardiogram (ECG) heartbeat, a new study reports.

Congestive heart failure (CHF) is a chronic progressive condition that affects the pumping power of the heart muscles. Associated with high prevalence, significant mortality rates and sustained healthcare costs, clinical practitioners and health systems urgently require efficient detection processes.

Dr Sebastiano Massaro, Associate Professor of Organisational Neuroscience at the University of Surrey, has worked with colleagues Mihaela Porumb and Dr Leandro Pecchia at the University of Warwick and Ernesto Iadanza at the University of Florence, to tackle these important concerns by using Convolutional Neural Networks (CNN) – hierarchical neural networks highly effective in recognising patterns and structures in data.

Published in Biomedical Signal Processing and Control Journal, their research drastically improves existing CHF detection methods typically focused on heart rate variability that, whilst effective, are time-consuming and prone to errors. Conversely, their new model uses a combination of advanced signal processing and machine learning tools on raw ECG signals, delivering 100% accuracy.

We trained and tested the CNN model on large publicly available ECG datasets featuring subjects with CHF as well as healthy, non-arrhythmic hearts. Our model delivered 100% accuracy: by checking just one heartbeat we are able detect whether or not a person has heart failure. Our model is also one of the first known to be able to identify the ECG’ s morphological features specifically associated to the severity of the condition,”  explains Dr Massaro.  Dr Pecchia, President at European Alliance for Medical and Biological Engineering, explains the implications of these findings: “With approximately 26 million people worldwide affected by a form of heart failure, our research presents a major advancement on the current methodology. Enabling clinical practitioners to access an accurate CHF detection tool can make a significant societal impact, with patients benefitting from early and more efficient diagnosis and easing pressures on NHS resources.”

Source: https://www.surrey.ac.uk/

How To Make Solar Panels More Sustainable And Cheaper

An innovative way to pattern metals has been discovered by scientists in the Department of Chemistry at the University of Warwick in UK, which could make the next generation of  solar panels more sustainable and cheaperSilver and copper are the most widely used electrical conductors in modern electronics and solar cells. However, conventional methods of patterning these metals to make the desired pattern of conducting lines are based on selectively removing metal from a film by etching using harmful chemicals or printing from costly metal inks.

Scientists from the Department of Chemistry at the University of Warwick, have developed a way of patterning these metals that is likely to prove much more sustainable and cheaper for large scale production, because there is no metal waste or use of toxic chemicals, and the fabrication method is compatible with continuous roll-to-roll processing. Dr Ross Hatton and Dr Silvia Varagnolo have discovered that silver and copper do not condense onto extremely thin films of certain highly fluorinated organic compounds when the metal is deposited by simple thermal evaporation.

Thermal evaporation is already widely used on a large scale to make the thin metal film on the inside of crisp packets, and organofluorine compounds are already common place as the basis of non-stick cooking pans. The researchers have shown that the organofluorine layer need only be 10 billionths of a metre thick to be effective, and so only tiny amounts are needed. This unconventional approach also leaves the metal surface uncontaminated, which Hatton believes will be particularly important for the next generation sensors, which often require uncontaminated patterned films of these metals as platforms onto which sensing molecules can be attached.

To help address the challenges posed by climate change, there is a need for colour tuneable, flexible and light weight solar cells that can be produced at low cost, particularly for applications where conventional rigid silicon solar cells are unsuitable such as in electric cars and semi-transparent solar cells for buildings. Solar cells based on thin films of organic, perovskite or nano-crystal semiconductors all have potential to meet this need, although they all require a low cost, flexible transparent electrode. Hatton and his team have used their method to fabricate semi-transparent organic solar cells in which the top silver electrode is patterned with millions of tiny apertures per square centimetre, which cannot be achieved by any other scalable means directly on top of an organic electronic device.

This innovation enables us to realise the dream of truly flexible, transparent electrodes matched to needs of the emerging generation of thin film solar cells, as well as having numerous other potential applications ranging from sensors to low-emissivity glass” explains Dr Hatton from the Department of Chemistry at the University of Warwick.

The work is published in the journal Materials Horizons.

Source: https://warwick.ac.uk/

Brain Metals Drive Alzheimer’s Progression

Alzheimer’s disease could be better treated, thanks to a breakthrough discovery of the properties of the metals in the brain involved in the progression of the neurodegenerative condition, by an international research collaboration including the University of Warwick.

Iron is an essential element in the brain, so it is critical to understand how its management is affected in Alzheimer’s disease. The advanced X-ray techniques that we used in this study have delivered a step-change in the level of information that we can obtain about iron chemistry in the amyloid plaques. We are excited to have these new insights into how amyloid plaque formation influences iron chemistry in the human brain, as our findings coincide with efforts by others to treat Alzheimer’s disease with iron-modifying drugs,” commented Dr Joanna Collingwood, from Warwick’s School of Engineering, who was part of a research team which characterised iron species associated with the formation of amyloid protein plaques in the human brainabnormal clusters of proteins in the brain. The formation of these plaques is associated with toxicity which causes cell and tissue death, leading to mental deterioration in Alzheimer’s patients.

They found that in brains affected by Alzheimer’s, several chemically-reduced iron species including a proliferation of a magnetic iron oxide called magnetite – which is not commonly found in the human brainoccur in the amyloid protein plaques. The team had previously shown that these minerals can form when iron and the amyloid protein interact with each other. Thanks to advanced measurement capabilities at synchrotron X-ray facilities in the UK and USA, including the Diamond Light Source I08 beamline in Oxfordshire, the team has now shown detailed evidence that these processes took place in the brains of individuals who had Alzheimer’s disease. They also made unique observations about the forms of calcium minerals present in the amyloid plaques.

The team, led by an EPSRC-funded collaboration between University of Warwick and Keele University – and which includes researchers from University of Florida and The University of Texas at San Antonio – made their discovery by extracting amyloid plaque cores from two deceased patients who had a formal diagnosis of Alzheimer’s. The researchers scanned the plaque cores using state-of-the-art X-ray microscopy at the Advanced Light Source in Berkeley, USA and at beamline I08 at the Diamond Light Source synchrotron in Oxfordshire, to determine the chemical properties of the minerals within them.

Source: https://warwick.ac.uk/

Squeeze And Get More Power Out Of Solar Cells

Physicists at the University of Warwick have published new research in the Journal Science  that could literally squeeze more power out of solar cells by physically deforming each of the crystals in the semiconductors used by photovoltaic cells. The paper entitled the “Flexo-Photovoltaic Effect” was written by Professor Marin Alexe, Ming-Min Yang, and Dong Jik Kim who are all based in the University of Warwick’s Department of Physics.

The Warwick researchers looked at the physical constraints on the current design of most commercial solar cells which place an absolute limit on their efficiency. Most commercial solar cells are formed of two layers creating at their boundary a junction between two kinds of semiconductors, p-type with positive charge carriers (holes which can be filled by electrons) and n-type with negative charge carriers (electrons). When light is absorbed, the junction of the two semiconductors sustains an internal field splitting the photo-excited carriers in opposite directions, generating a current and voltage across the junction. Without such junctions the energy cannot be harvested and the photo-exited carriers will simply quickly recombine eliminating any electrical charge. That junction between the two semiconductors is fundamental to getting power out of such a solar cell but it comes with an efficiency limit. This Shockley-Queisser Limit means that of all the power contained in sunlight falling on an ideal solar cell in ideal conditions only a maximum of 33.7% can ever be turned into electricity.

There is however another way that some materials can collect charges produced by the photons of the sun or from elsewhere. The bulk photovoltaic effect occurs in certain semiconductors and insulators where their lack of perfect symmetry around their central point (their non-centrosymmetric structure) allows generation of voltage that can be actually larger than the band gap of that material. Unfortunately the materials that are known to exhibit the anomalous photovoltaic effect have very low power generation efficiencies, and are never used in practical power-generation systems. The Warwick team wondered if it was possible to take the semiconductors that are effective in commercial solar cells and manipulate or push them in some way so that they too could be forced into a non-centrosymmetric structure and possibly therefore also benefit from the bulk photovoltaic effect.

Extending the range of materials that can benefit from the bulk photovoltaic effect has several advantages: it is not necessary to form any kind of junction; any semiconductor with better light absorption can be selected for solar cells, and finally, the ultimate thermodynamic limit of the power conversion efficiency, so-called Shockley-Queisser Limit, can be overcome“,  explains Professor Marin Alexe  (University of Warwick).

Source: https://warwick.ac.uk/