Category: Battery News

Researchers at the University of Illinois at Chicago have taken a significant step toward the development of a battery that could outperform the lithium-ion technology used in electric cars.

They have shown they can replace the lithium ions, each of which carries a single positive charge, with magnesium ions, which have a plus-two charge, in battery-like chemical reactions, using an electrode with a structure like those in many of today's devices.

"Because magnesium is an ion that carries two positive charges, every time we introduce a magnesium ion in the structure of the battery material we can move twice as many electrons," says Jordi Cabana, UIC assistant professor of chemistry and principal investigator on the study.

"We hope that this work will open a credible design path for a new class of high-voltage, high-energy batteries," Cabana said.

The research is part of the Joint Center for Energy Storage Research, a Department of Energy Innovation Hub led by Argonne National Laboratory, that aims to achieve revolutionary advances in battery performance. The study is online in advance of print in the journal Advanced Materials.

Every battery consists of a positive and negative electrode and an electrolyte. The electrodes exchange electrons and ions, which are usually of positive charge. Only the ions flow through the electrolyte, which is an electric insulator so as to force the electrons to flow through the external circuit to power the vehicle or device.

To recharge the battery, the exchange is reversed. But the chemical reaction is not perfectly efficient, which limits how many times the battery can be recharged.

"The more times you can do this back and forth, the more times you will be able to recharge your battery and still get the use of it between charges," Cabana said.

"In our case, we want to maximize the number of electrons moved per ion, because ions distort the structure of the electrode material when they go in or leave. The more the structure is distorted, the greater the energy cost of moving the ions back, the harder it becomes to recharge the battery."

"Like a parking garage, there are only so many spaces for the cars," Cabana said. "But you can put a car in each space with more people inside without distorting the structure."

Having established that magnesium can be reversibly inserted into electrode material's structure brings us one step closer to a prototype, said Cabana.

"It's not a battery yet, it's piece of a battery, but with the same reaction you would find in the final device," said Cabana.

According to the Wall Street Journal, Google’s X research lab is working on a project to improve battery technology. This group is led by Dr Ramesh Bhardwaj, a former Apple employee who worked on batteries there, too.

WSJ is reporting that Bhardwaj and his 4-member team reportedly originally tested batteries that were developed by others for use in Google devices, but have since switched gears and may even develop the new battery tech themselves. Apparently their focus area is improving Li-Ion technology and solid state batteries for consumer devices.

Dr. Bhardwaj has told industry executives that Google has at least 20 battery-dependent projects including the company’s latest self-driving car. “Google wants to control more of their own destiny in various places along the hardware supply chain,” said Lior Susan, head of hardware strategy at venture-capital firm Formation 8. “Their moves into drones, cars and other hardware all require better batteries.”

Google joins many technology companies trying to improve batteries, including Apple, Tesla Motors Inc. and International Business Machines Corp. These efforts have so far produced only incremental gains, a contrast for tech companies accustomed to regular, dramatic leaps in the efficiency of semiconductors.

Emerging battery technologies promise bigger gains. Solid-state, thin-film batteries use a solid, rather than liquid, making them smaller and safer. Such batteries can be produced in thin, flexible layers, useful for small mobile devices. But it isn’t clear whether they can be mass produced cheaply, said Venkat Srinivasan, a researcher at Lawrence Berkeley National Lab.

Source: WSJ

Stanford University scientists have invented the first high-performance aluminium battery that's fast-charging, long-lasting and inexpensive. Researchers say the new technology offers a safe alternative to many commercial batteries in wide use today.

"We have developed a rechargeable aluminium battery that may replace existing storage devices, such as alkaline batteries, which are bad for the environment, and lithium-ion batteries, which occasionally burst into flames," said Hongjie Dai, a professor of chemistry at Stanford. "Our new battery won't catch fire, even if you drill through it."

Dai and his colleagues describe their novel aluminium-ion battery in "An ultrafast rechargeable aluminium-ion battery," which will be published in the April 6 advance online edition of the journal Nature.

Aluminium has long been an attractive material for batteries, mainly because of its low cost, low flammability and high-charge storage capacity. For decades, researchers have tried unsuccessfully to develop a commercially viable aluminium-ion battery. A key challenge has been finding materials capable of producing sufficient voltage after repeated cycles of charging and discharging.

Graphite cathode
An aluminium-ion battery consists of two electrodes: a negatively charged anode made of aluminium and a positively charged cathode.

"People have tried different kinds of materials for the cathode," Dai said. "We accidentally discovered that a simple solution is to use graphite, which is basically carbon. In our study, we identified a few types of graphite material that give us very good performance."

For the experimental battery, the Stanford team placed the aluminium anode and graphite cathode, along with an ionic liquid electrolyte, inside a flexible polymer- coated pouch.

"The electrolyte is basically a salt that's liquid at room temperature, so it's very safe," said Stanford graduate student Ming Gong, co-lead author of the Nature study.

Aluminium batteries are safer than conventional lithium-ion batteries used in millions of laptops and cell phones today, Dai added.

"Lithium-ion batteries can be a fire hazard," he said.

As an example, he pointed to recent decisions by United and Delta airlines to ban bulk lithium-battery shipments on passenger planes.

"In our study, we have videos showing that you can drill through the aluminium battery pouch, and it will continue working for a while longer without catching fire," Dai said. "But lithium batteries can go off in an unpredictable manner – in the air, the car or in your pocket. Besides safety, we have achieved major breakthroughs in aluminium battery performance."

One example is ultra-fast charging. Smartphone owners know that it can take hours to charge a lithium-ion battery. But the Stanford team reported "unprecedented charging times" of down to one minute with the aluminum prototype.

Durability is another important factor. Aluminium batteries developed at other laboratories usually died after just 100 charge-discharge cycles. But the Stanford battery was able to withstand more than 7,500 cycles without any loss of capacity. "This was the first time an ultra-fast aluminium-ion battery was constructed with stability over thousands of cycles," the authors wrote.

By comparison, a typical lithium-ion battery lasts about 1,000 cycles.

"Another feature of the aluminium battery is flexibility," Gong said. "You can bend it and fold it, so it has the potential for use in flexible electronic devices. Aluminium is also a cheaper metal than lithium."

Applications
In addition to small electronic devices, aluminium batteries could be used to store renewable energy on the electrical grid, Dai said.

"The grid needs a battery with a long cycle life that can rapidly store and release energy," he explained. "Our latest unpublished data suggest that an aluminium battery can be recharged tens of thousands of times. It's hard to imagine building a huge lithium-ion battery for grid storage."

Aluminium-ion technology also offers an environmentally friendly alternative to disposable alkaline batteries, Dai said.

"Millions of consumers use 1.5-volt AA and AAA batteries," he said. "Our rechargeable aluminium battery generates about two volts of electricity. That's higher than anyone has achieved with aluminium."

But more improvements will be needed to match the voltage of lithium-ion batteries, Dai added.

"Our battery produces about half the voltage of a typical lithium battery," he said. "But improving the cathode material could eventually increase the voltage and energy density. Otherwise, our battery has everything else you'd dream that a battery should have: inexpensive electrodes, good safety, high-speed charging, flexibility and long cycle life. I see this as a new battery in its early days. It's quite exciting."

Korean researchers have developed super capacitor battery with twice as large capacity and ten times faster charge speed than conventional batteries controlling two dimensional nanomaterial structure and composition. The technology is widely expected to facilitate the development of ultra super capacitor material utilized in next generation energy industry such as electric vehicles and smart grids.

The electric double layer capacitors (EDLC) boasts high power output, faster recharge and discharge, and semi-permanent battery life. However, low energy density can restrict the application. EDLC is a type of super capacitor that stores or discharges energy within seconds by absorbing ion electrically pulled from the electrode surface.

A series of research has been conducted in advanced countries including the US to enhance the energy density by developing super capacitor electrode material. The research team found secondary nanosheet by chemically exfoliating the bulk layered compound made of transitional metal and sulfur as they would to retrieve graphene shedding off a layer of graphite before they build the two dimensional nanosheet into a three dimensional structure.

The result was published in a science magazine ‘Nano Letters’ on March 3, titled as ‘Unveiling Surface Redox Charge Storage of Interacting Two-Dimensional Heteronanosheets in Hierarchical Architectures.’