Thu.Aug 22, 2019

TeraWatt Technology solid-state battery prototype tests showing 432 kWh/kg

Green Car Congress

TeraWatt Technology announced that its 4.5Ah prototype solid-state battery design achieved a record-breaking energy density of 432Wh/kg (1122Wh/L) in validation tests conducted by third parties, including TOYO System based in Japan. Branded as TERA3.0,

2019 160

Best deals on plug-in, hybrid, and electric cars for August 2019

Green Car Reports

Auto-loan interest rates have started to fall slightly in August—but that hasn't yet made it any easier to find great deals on plug-in, hybrid, and electric cars. And yet, the deals are out there. Our partners at CarsDirect.com found deals as low as $179 a month in August.

2019 104

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Study identifies main culprit behind lithium metal battery failure; counters conventional wisdom

Green Car Congress

A research team led by the University of California San Diego, with colleagues from San Diego State University, US Army Research Laboratory, and General Motors Research and Development Center, has discovered the root cause of why lithium metal batteries fail: bits of lithium metal deposits break off from the surface of the anode during discharging and are trapped as “dead” or inactive lithium that the battery can no longer access. The discovery, published in Nature , challenges the conventional belief that lithium metal batteries fail because of the growth of the solid electrolyte interphase (SEI) between the lithium anode and the electrolyte. The researchers made their discovery by developing a technique to measure the amounts of inactive lithium species on the anode—a first in the field of battery research—and studying their micro- and nanostructures. The findings could pave the way for bringing rechargeable lithium metal batteries from the lab to the market. By figuring out the major underlying cause of lithium metal battery failure, we can rationally come up with new strategies to solve the problem. Our ultimate goal is to enable a commercially viable lithium metal battery. —first author Chengcheng Fang, a materials science and engineering Ph.D. student at UCSD. Lithium metal batteries, which have anodes made of lithium metal, are an essential part of the anticipated next-generation of battery technologies. They promise twice the energy density of today’s lithium-ion batteries with graphite anodes, so they could last longer and weigh less. This could potentially double the range of electric vehicles. However, a major issue with lithium metal batteries is low Coulombic efficiency—i.e., they undergo a limited number of cycles before they stop working. As the battery cycles, its stores of active lithium and electrolyte are depleted. Battery researchers have long suspected that this is due to the growth of the solid electrolyte interphase (SEI) layer between the anode and the electrolyte. But although researchers have developed various ways to control and stabilize the SEI layer, they still have not fully resolved the problems with lithium metal batteries, explained senior author Y. Shirley Meng, a nanoengineering professor at UC San Diego. The cells still fail because a lot of inactive lithium is forming in these batteries. So there is another important aspect that is being overlooked. —Professor Meng. The culprits, Meng, Fang and colleagues found, are lithium metal deposits that break off of the anode when the battery is discharging and then get trapped in the SEI layer. There, they lose their electrical connection to the anode, becoming inactive lithium that can no longer be cycled through the battery. This trapped lithium is largely responsible for lowering the Coulombic efficiency of the cell. The researchers identified the culprit by creating a method to measure how much unreacted lithium metal gets trapped as inactive lithium. Water is added to a sealed flask containing a sample of inactive lithium that formed on a cycled half-cell. Any bits of unreacted lithium metal chemically react with water to produce hydrogen gas. By measuring how much gas is produced, researchers can calculate the amount of trapped lithium metal. Inactive lithium is also made up of another component: lithium ions, which are the building blocks of the SEI layer. Their amount can also be calculated simply by subtracting the amount of unreacted lithium metal from the total amount of inactive lithium. In tests on lithium metal half-cells, researchers found that unreacted lithium metal is the main ingredient of inactive lithium. As more of it forms, the lower the Coulombic efficiency sinks. Meanwhile, the amount of lithium ions from the SEI layer consistently stays low. These results were observed in eight different electrolytes. This is an important finding because it shows that the primary failure product of lithium metal batteries is unreacted metallic lithium instead of the SEI. This is a reliable method to quantify the two components of inactive lithium with ultra-high accuracy, which no other characterization tool has been capable of doing. —Chengcheng Fang. The aggressive chemical nature of lithium metal has made this task very challenging. Parasitic reactions of many different types occur simultaneously on lithium metal, making it almost impossible to differentiate these different types of inactive lithium. The advanced methodology established in this work provides a very powerful tool to do this in a precise and reliable way. —Kang Xu, whose team at the US Army Combat Capabilities Development Command Army Research Laboratory provided one of the advanced electrolyte formulations to test the method. The researchers hope their method could become the new standard for evaluating efficiency in lithium metal batteries. One of the problems battery researchers face is that testing conditions are very different across labs, so it’s hard to compare data. It’s like comparing apples to oranges. Our method can enable researchers to determine how much inactive lithium forms after electrochemical testing, regardless of what type of electrolyte or cell format they use. —Professor Meng. By studying the micro- and nanostructures of lithium deposits in different electrolytes, the researchers answer another important question: why some electrolytes improve Coulombic efficiency while others do not. SEM images of cross sections of lithium deposits, which vary in structure depending on the type of electrolyte used. Left: Columnar microstructure which leads to high Coulombic efficiency. Right: Porous, tortuous, whisker-like microstructure which lowers Coulombic efficiency. Image courtesy of Meng lab/ Nature. The answer has to do with how lithium deposits on the anode when the cell is charging. Some electrolytes cause lithium to form micro- and nanostructures that boost cell performance. For example, in an electrolyte specially designed by Meng’s collaborators at General Motors, lithium deposits as dense, column-shaped chunks. This type of structure causes less unreacted lithium metal to get trapped in the SEI layer as inactive lithium during discharge. The result is a Coulombic efficiency of 96% for the first cycle. This excellent performance is attributed to the columnar microstructure formed on the surface of the current collector with minimum tortuosity, which significantly enhances the structural connection. —Mei Cai, whose team at GM developed the advanced electrolyte that enabled lithium to deposit with the “ideal” microstructure. In contrast, when a commercial carbonate electrolyte is used, lithium deposits with a twisty, whisker-like morphology. This structure causes more lithium metal to get trapped in the SEI during the stripping process. Coulombic efficiency lowers to 85%. Moving forward, the team proposes strategies to control the depositing and stripping of lithium metal. These include applying pressure on the electrode stacks; creating SEI layers that are uniform and mechanically elastic; and using 3D current collectors. Control of the micro- and nanostructure is key. We hope our insights will stimulate new research directions to bring rechargeable lithium metal batteries to the next level. —Professor Meng. This work was supported by the Office of Vehicle Technologies of the US Department of Energy through the Advanced Battery Materials Research Program (Battery500 Consortium, contract DE-EE0007764). This work was performed in part at the San Diego Nanotechnology Infrastructure, a member of the National Nanotechnology Coordinated Infrastructure, which is supported by the National Science Foundation (grant ECCS-1542148); the UC Irvine Materials Research Institute, which is funded in part by the National Science Foundation Major Research Instrumentation Program (grant CHE-1338173); and the lab of Ivan K. Schuller at UC San Diego, which is supported in part by the Office of Basic Energy Science, US Department of Energy. Resources. Chengcheng Fang, Jinxing Li, Minghao Zhang, Yihui Zhang, Fan Yang, Jungwoo Z. Lee, Min-Han Lee, Judith Alvarado, Marshall A. Schroeder, Yangyuchen Yang, Bingyu Lu, Nicholas Williams, Miguel Ceja, Li Yang, Mei Cai, Jing Gu, Kang Xu, Xuefeng Wang & Ying Shirley Meng (2019) “Quantifying inactive lithium in lithium metal batteries” Nature volume 572, pages 511–515 doi: 10.1038/s41586-019-1481-z. Batteries

2019 136

Survey: Range, cost, infrastructure sum up why shoppers avoid EVs

Green Car Reports

We’ve heard it repeatedly as the result of various polls and surveys: Active and prospective car shoppers are interested in fully electric vehicles and eager to go electric.

2019 104

Increased relative contribution of medium and heavy trucks to U.S. greenhouse gas emissions

Green Car Congress

by Michael Sivak. In this analysis, I examined recent changes in the contribution of transportation to total greenhouse gas emissions in the United States relative to the other sources of emissions (industry, commercial, residential, and agriculture).

2019 122

Mercedes introduces longer-range EQV electric van

Green Car Reports

Mercedes-Benz plans to introduce the second in its new EQ line of electric vehicles, the EQV van, at next month's Frankfurt auto show. The company says that a 100-kwh battery pack under the floor will deliver 250 miles of range on the European driving cycle.

2019 95

Volvo extends S60 range with plug-in hybrid powertrain and new trim levels

Green Car Congress

Volvo has extended its S60 range—the third generation of the premium mid-size sedan—to incorporate further powertrain choices and equipment grades, including an all­wheel­drive gasoline-electric hybrid and a trim level that focuses on luxury and craftsmanship.

2019 119

More Trending

Blue World Technologies takes 15% stake in Danish Power Systems; methanol fuel cell vehicles

Green Car Congress

Blue World Technologies has acquired 15% of Danish Power Systems , a developer and manufacturer of membrane electrode assemblies (MEAs) for high-temperature PEM fuel cells. Blue World Technologies will use the Danish Power Systems technology in their methanol fuel cell systems.

2019 114

Walmart lawsuit takes aim at Tesla solar panels

Green Car Reports

Walmart sued Tesla on Tuesday, alleging that solar panels that Tesla installed on seven Walmart stores caught fire. The lawsuit accuses Tesla of breach of contract, negligence, and failing to live up to industry standards, according to the court filing. Walmart alleges that the fires resulted in evacuations, and damage to property and inventory. solar Walmart

2019 73

Major international study links short-term exposure to PM pollution to risk of premature death

Green Car Congress

A major new international study shows independent associations between short-term exposure to PM 10 and PM 2.5 and daily all-cause, cardiovascular, and respiratory mortality in more than 600 cities across the globe. These data reinforce the evidence of a link between mortality and PM concentration established in regional and local studies, according to the researchers.

2019 86

Hyundai 45 EV concept for Frankfurt show to highlight new design language

Green Car Reports

Hyundai announced last week that it will show a concept car “envisioning its future EV design direction” at next month’s Frankfurt auto show.

2019 70

Altalto waste-to-jet fuel plant advances in UK; BA, Shell, Velocys

Green Car Congress

Altalto Immingham Limited, a subsidiary of renewable fuels company Velocys and a collaboration with British Airways and Shell, has submitted a planning application to develop its site in Immingham, North East Lincolnshire, close to the Humber Estuary. Velocys is leading the development of the project and has assembled all the technology components into a standardized integrated design.

2019 83

Walmart lawsuit takes aim at Tesla solar panels (Updated)

Green Car Reports

Walmart sued Tesla on Tuesday, alleging that solar panels that Tesla installed on seven Walmart stores caught fire. The lawsuit accuses Tesla of breach of contract, negligence, and failing to live up to industry standards, according to the court filing. Walmart alleges that the fires resulted in evacuations, and damage to property and inventory. solar Walmart

2019 66

Porsche invests in Israeli start-up TriEye; SWIR technology for automated driving

Green Car Congress

Porsche has acquired a minority stake in the Israeli start-up, TriEye. The newly established company has developed a sensor technology for short-wave infrared (SWIR). It enhances safety in vehicles fitted with assistance systems or autonomous driving functions by improving the ability to see in weather conditions where visibility is poor, such as dust, fog, murky conditions or rain. TriEye enables SWIR capabilities with a CMOS-based image sensor.

2019 79

Tesla solar fires, Mercedes-Benz electric van, August deals: Today's Car News

Green Car Reports

Walmart sues Tesla over solar panel fires at its stores. Mercedes-Benz released a new electric van. A new survey shows the top reasons consumers avoid buying EVs. And we run down the best deals on plug-in, hybrid, and electric cars. All this and more on Green Car Reports. A new survey by Autolist shows some familiar reasons why so many Americans. Today in Car News

2019 56

Volkswagen set for massive overhaul with new design and logo

Green Cars News

The upcoming Frankfurt Motor Show will be a big one for Volkswagen

2019 62

Review: Skoda Kodiaq vRS

Green Cars News

Skoda is rightly proud of its vRS branding

2019 59

Mercedes EQV: premium electric MPV gets 252-mile range

Green Cars News

Mercedes-Benz has revealed its EQV – a large, all-electric MPV that offers a premium interior

2019 55

Government should encourage usership over ownership, MPs find

Green Cars News

The government should be encouraging car usership rather than ownership if it is to deliver its net-zero emissions by 2050 target, a group of MPs have said

2019 48

Colour guide: How much difference does colour make to the Range Rover Evoque?

Green Cars News

The 2019 Range Rover Evoque is proving to be an extremely popular lease

2019 48