Archive : 13 January 2016 год

Scientists at three Department of Energy national laboratories claim to have discovered how to keep a lithium ion battery cathode from developing a coating that degrades its performance. The teams used a manufacturing technique to form the cathode material into tiny, layered particles that store a lot of energy while protecting themselves from damage.

The scientists reported that the test batteries that included this cathode material held up better when charged and discharged at the voltages needed to fast-charge electric vehicles.

"We were able to engineer the surface in a way that prevents rapid fading of the battery's capacity," said Yijin Liu, a staff scientist at SLAC National Accelerator Laboratory. The results potentially pave the way for making lithium-ion batteries that are cheaper and have higher energy density.

Cathodes made of nickel manganese cobalt oxide (NMC) are an especially hot area of battery research because they can operate at the voltages needed to store a lot of energy in a very small space.

But, Huolin Xin of Brookhaven National Laboratory said, while the nickel in NMC gives it a high capacity for storing energy, it's also reactive and unstable, with a tendency to undergo destructive side reactions with the electrolyte. Over time this forms a rock salt-like crust that blocks the flow of lithium ions.

In this study, the researchers experimented with ways to incorporate nickel but protect it from the electrolyte.

A team led by Marca Doeff at Lawrence Berkeley National Laboratory sprayed a solution of lithium, nickel, manganese and cobalt through an atomiser nozzle to form droplets that decomposed to form a powder. Repeatedly heating and cooling the powder triggered the formation of tiny particles that assembled themselves into larger, spherical and sometimes hollow structures.

This technique, called spray pyrolysis, is said to be cheap and could be scaled up for commercial production. During this process the NMC particles emerged with their basic ingredients redistributed.

The cathode particles were examined at SLAC and Brookhaven. At SLAC's Stanford Synchrotron Radiation Lightsource, Liu and his colleagues used X-rays to probe the particles at a scale of 10 to 20µm. At Brookhaven's Centre for Functional Nanomaterials, Xin and his team used a scanning transmission electron microscope to zoom in on nanoscale details.

With both techniques and at every scale they looked, the particles had a different structure than the original starting material. Only 70% of them contained all three of the starting metals - nickel, manganese and cobalt.

"The particles have more nickel on the inside, to store more energy, and less on the surface, where it would cause problems," Liu said. At the same time, the surface of the particles was enriched in manganese, which acted like a coat of paint to protect the interior.

In future experiments, the researchers plan to probe the NMC cathode with X-rays while it's charging and discharging to see how its structure and chemistry change. They also hope to improve the material's safety.

"To make a real, functional battery that can be commercialised, you have to look beyond performance," Liu said. "Safety and many other things have to be considered."

Author
Tom Austin-Morgan

Source:  www.newelectronics.co.uk

Last month, IBM opened a new global headquarters for its Watson Internet of Things (IoT) unit in Munich. At the launch, the company made a series of announcements – including new offerings, capabilities and partners – with the aim being to extend cognitive computing into the rapidly evolving IoT world by deploying IBM’s Watson IoT Cloud platform.

“The IoT will soon be the largest single source of data on the planet, yet almost 90% of that data is never acted upon,” said Harriet Green, general manager, Watson IoT and Education. “With its abilities to sense, reason and learn, Watson opens the door for enterprises, governments and individuals to harness real-time data, compare it with historical data sets and then find unexpected correlations leading to new insights.”

Speaking to New Electronics prior to the event, Bret Greenstein, VP of IoT for IBM, explained: “Cognitive computing is a new class of systems that are capable of learning at scale, can reason with purpose and interact with humans naturally. Rather than being explicitly programmed, these devices learn and reason from their interactions with us and from their experiences with their environment, enabling them to keep pace with the volume, complexity and unpredictability of information generated by the IoT. Business is being transformed around companies by the rise of IoT and everything is happening at a compressed timescale.”

The decision to base the operation – the company’s largest investment in Europe in more than two decades – in Munich was driven by the depth and breadth of opportunities provided by the German market.

“While the IoT is everywhere,” Greenstein explained, “Industry 4.0 started in Germany and businesses here have played an important part not only in leading innovation but in terms of standards and market leadership.

“Munich provides IBM with a centre of gravity and a chance to bring the best minds in Europe together in one location.” The Munich site will also be the home for IBM’s first European Watson innovation centre.

According to Greenstein: “This new campus will bring together IBM developers, consultants, researchers and designers to drive deeper engagement with both clients and partners. It will also serve as an innovation lab for data scientists, engineers and programmers, who will be working to deliver connected solutions at the intersection of cognitive computing and the IoT to create new opportunities for growth.”

IBM is also opening eight new Watson IoT Client Experience Centers across Asia, Europe and the Americas. The centres are located in Beijing, Boeblingen, Sao Paulo, Seoul and Tokyo, as well as in Massachusetts, North Carolina and Texas.

These centres are intended to provide clients and partners with access to the technology, tools and talent needed to develop and create new products and services using cognitive intelligence delivered through the Watson IoT Cloud Platform.

IBM also unveiled four families of Watson API services that are being made available as part of the company’s Watson IoT Analytics offering.

These include: the Natural Language Processing (NLP) API Family, which enables users to interact with systems and devices using simple, human language; the Machine Learning Watson API Family, which automates data processing and monitors new data and user interactions to rank data and results based on learned priorities; a Video and Image Analytics API Family; and a Text Analytics API Family that can mine unstructured textual data, including transcripts from customer call centres, maintenance technician logs, blog comments and tweets to find correlations and patterns in these vast amounts of data.

Author
Neil Tyler

Source:  www.newelectronics.co.uk