Tag: solid-state batteries

Seawater: The next sustainable battery revolution

Seawater: The next sustainable battery revolution

International team shows that with minor modifications chloride is effective electrode material for solid-state batteries

Seawater covers most of the globe and makes up around 97 per cent of all water on Earth. It could also hold the key to cheaper and greener batteries for storing green energy collected from wind turbines and solar cells.

Using the Canadian Light Source (CLS) at the University of Saskatchewan, an international research team involving scientists from Switzerland, Canada, and the United States, has shown that with some minor modifications, chloride – a sustainable and readily available component of seawater – could one day be the material that shuttles ions back and forth between the electrodes in solid-state batteries used for grid-scale energy storage.

Lithium is currently at the heart of modern batteries, powering everything from our smartphones to e-bikes and electric cars. But there’s a very real risk that the material could become scarcer and more expensive in the future. According to Natural Resources Canada, lithium production has more than doubled world-wide in in the past five years. And a handful of countries hold most of the planet’s lithium stores. Canada’s supplies amount to only 4.4 per cent of the total worldwide.

“We’re not looking to entirely replace lithium-ion batteries, but we need other solutions in the next few decades if we are going to meet this massive need that the world will have for hundreds of terawatt hours that allow for effective use of solar and wind,” said Sarbajit Banerjee, professor at ETH Zürich, a public university in Switzerland, and Head of the Laboratory for Battery Science at Switzerland’s Paul Scherrer Institute.

Read more on the CLS website

Image: Seaweed batteries – X-ray Excited Optical Luminescence Spectroscopy

BESSY II: How intrinsic oxygen shortens the lifespan of solid-state batteries

BESSY II: How intrinsic oxygen shortens the lifespan of solid-state batteries

Although solid-state batteries (SSBs) demonstrate high performance and are intrinsically safe, their capacity currently declines rapidly. A team from the TU Wien, Humboldt-University Berlin and HZB has now analysed a TiS₂|Li₃YCl₆ solid-state half-cell in operando at BESSY II using a special sample environment that allows for non-destructive investigation under real operating conditions. Data obtained by combination of soft and hard X-ray photoelectron spectroscopy (XPS and HAXPES) revealed a new degradation mechanism that had not previously been identified in solid-state batteries. They have gained some surprising insights, particularly regarding the harmful role played by intrinsic oxygen. This study provides valuable information for improving design and handling of such batteries.

Solid-state batteries (SSBs) offer several advantages over conventional batteries, including higher energy and power densities, as well as greater safety, as they do not contain flammable liquid electrolytes. However, since lithium ions migrate between the working electrode and the counter-electrode during operation, the solid material can suffer by volume changes, which can lead to cracks. In order to maintain contact between electrodes and electrolyte, SSBs must be operated under high pressure. Volume changes, as well as degradation processes at the interfaces, often limit the lifespan of these batteries. Until now, it has been virtually impossible to observe these processes experimentally, particularly due to the high stacking pressure required during operation. However, Dr Elmar Kataev, a scientist at HZB, has now developed a sample environment that enables operando analysis of SSBs under high pressure using two-colour – soft and hard – X-ray photoelectron spectroscopy (XPS and HAXPES) at the SISSY endstation at BESSY II. These conditions of combining two different energies of X-rays (hard for bulk sensitivity and soft – for surface) hitting the same spot is exclusively available at EMIL beamline.

Read more on the HZB website

Image: A view of the operando cell in the sample chamber during the measurements at the SISSY Endstation.

Credit: © E. Kataev/HZB

BESSY II shows how solid-state batteries degrade

BESSY II shows how solid-state batteries degrade

Solid-state batteries have several advantages: they can store more energy and are safer than batteries with liquid electrolytes. However, they do not last as long and their capacity decreases with each charge cycle. But it doesn’t have to stay that way: Researchers are already on the trail of the causes. In the journal ACS Energy Letters, a team from HZB and Justus-Liebig-Universität, Giessen, presents a new method for precisely monitoring electrochemical reactions during the operation of a solid-state battery using photoelectron spectroscopy at BESSY II. The results help to improve battery materials and design.

Solid-state batteries use a solid ion conductor between the battery electrodes instead of a liquid electrolyte, which allows lithium to be transported during charging and discharging. This has advantages including increased safety during operation and generally higher capacity.  However, the lifetime of solid-state batteries is still very limited. This is because decomposition products and interphases form at the interfaces between the electrolyte and the electrode, which hinders the transport of the lithium ions and leads to consumption of active lithium so that the capacity of the batteries decreases with each charge cycle.

What happens during operation?

Now a team led by HZB researchers Dr. Elmar Kataev and Prof. Marcus Bär has developed a new approach to analyse the electrochemical reactions at the interface between solid electrolyte and electrode with high temporal resolution. Kataev explains the research question: “Under what conditions and at what voltage do such reactions occur, and how does the chemical composition of these intermediate phases evolve during cell operation?”

Best candidate LiPSCl examined

For the study, they analysed samples of the solid electrolyte Li6PS5Cl, a material that is considered the best candidate for solid-state batteries as it possesses high ionic conductivity. They worked closely with the team of battery expert Professor Jürgen Janek from the Justus Liebig University Giessen (JLU Giessen). An extremely thin layer of nickel (30 atomic layers or 6 nanometres) served as the working electrode. A film of lithium was pressed onto the other side of the Li6PS5Cl pellet to act as a counter electrode.

Read more on HZB website

Image: SEM images of LPSCl pellets before (left) and after (right) the operando HAXPES experiment

Findings pave way for longer-lasting solid-state batteries

Findings pave way for longer-lasting solid-state batteries

Lithium-ion batteries contain flammable materials that could pose a safety risk under certain conditions. Dr. Yaser Abu-Lebdeh is one of the researchers using the Canadian Light Source (CLS) at the University of Saskatchewan to develop a safer alternative: solid-state batteries.

Solid-state batteries replace the flammable liquid electrolyte in conventional batteries with a solid ceramic-based material to pass charge through the battery.

“These oxide-based ceramics or ceramic oxides, are intrinsically safe, meaning they’re not volatile, they’re not flammable,” says Dr. Abu-Lebdeh, a team leader with the National Research Council of Canada’s battery materials innovation team.

The batteries have another major advantage: they enable the use of lithium metal and hence are able to hold a great deal of charge in a small space, making them powerful energy storage devices.

As with any new technology, there have been hiccups in the development.

“We’ve run into a problem where the batteries lose their capacity very quickly, meaning they die out very, very quickly,” says Dr. Abu-Lebdeh.

Standard lab techniques couldn’t pinpoint what was causing the early failure, so Dr. Abu-Lebdeh turned to his longtime collaborators at the CLS. Using synchrotron light — which is particularly well suited for studying batteries — they were able to identify the root causes of the battery’s premature failure: a combination of tiny structural changes and chemical changes happening in two different parts of the battery.

Dr. Abu-Lebdeh says the new insights will help them improve the mix of solid and liquid parts and how these batteries are put together. They published the results in the Journal of Physical Chemistry.

Read more on CLS website

New study could help unlock ‘game-changing’ batteries for electric vehicles and aviation

New study could help unlock ‘game-changing’ batteries for electric vehicles and aviation

Significantly improved electric vehicle (EV) batteries could be a step closer thanks to a new study led by University of Oxford researchers, published today in Nature. Using advanced imaging techniques, this revealed mechanisms which cause lithium metal solid-state batteries (Li-SSBs) to fail. If these can be overcome, solid-state batteries using lithium metal anodes could deliver a step-change improvement in EV battery range, safety and performance, and help advance electrically powered aviation.

One of the co-lead authors of the study Dominic Melvin, a PhD student in the University of Oxford’s Department of Materials, said:

Progressing solid-state batteries with lithium metal anodes is one of the most important challenges facing the advancement of battery technologies. While lithium-ion batteries of today will continue to improve, research into solid-state batteries has the potential to be high-reward and a gamechanger technology.

Li-SSBs are distinct from other batteries because they replace the flammable liquid electrolyte in conventional batteries with a solid electrolyte and use lithium metal as the anode (negative electrode). The use of the solid electrolyte improves the safety, and the use of lithium metal means more energy can be stored. A critical challenge with Li-SSBs, however, is that they are prone to short circuit when charging due to the growth of ‘dendrites’: filaments of lithium metal that crack through the ceramic electrolyte. As part of the Faraday Institution’s SOLBAT project, which Diamond is a partner, researchers have led a series of in-depth investigations to understand more about how this short-circuiting happens.

In this latest study, the group used an advanced imaging technique called X-ray Computed Tomography (X-ray CT) at the I13-2 beamline of Diamond Light Source to visualise dendrite failure in unprecedented detail during the charging process.

Read more on the Diamond website