Research Explores How Rechargeable Batteries Degrade
Rechargeable battery performance could be improved by a new understanding of how they work at the molecular level. For decades, researchers have assumed that the inevitable filmy buildup on electrodes inside rechargeable batteries is the driver of performance loss. Research shows that view is backward.
The research report has been published in Nature Energy.
The buildup of mossy or tree-like structured lithium metal deposits on battery electrodes is not the root cause of performance loss, but rather a side effect. The report shows the first direct measurement of the electrical properties at the boundary between the solid electrode and the liquid electrolyte inside a rechargeable battery.
The study, led by a research team at the Department of Energy’s Pacific Northwest National Laboratory, shows that the so-called solid electrolyte interphase (SEI) is not an electronic insulator, as previously thought, but instead behaves like a semiconductor. The research solves the long-standing mystery of how SEI functions electrically during battery operation.
Chongmin Wang, a PNNL Laboratory Fellow and battery technology expert who co-led the study said, “A higher rate of electrical conductance induces a thicker SEI with intricate solid lithium forms, ultimately leading to inferior battery performance.”
Micro-sized battery upends assumptions about how rechargeable batteries work
The researchers focused on this SEI layer, which is thinner than a sheet of tissue paper, because of its out-sized role in battery performance. This filmy mosaic selectively permits charged lithium ions to cross during discharge and controls movement of electrons that supply the battery’s power.
When batteries are new, the SEI forms on the first charging cycle and ideally remains stable during the battery’s expected lifespan. But a look inside an aging rechargeable battery often reveals substantial buildup of solid lithium on the negative electrodes. Battery researchers have assumed that this buildup causes the performance losses. Part of the reason for this guess work has been an inability to make measurements to test cause and effect.
Wang, along with co-lead of the study Wu Xu, a materials scientist of PNNL’s Battery Materials and Systems Group, co-first authors Yaobin Xu and Hao Jia, and their colleagues at PNNL, Texas A&M University, and Lawrence Berkeley National Laboratory solved this problem by developing a new technique to directly measure electrical conduction across the SEI in an experimental system. The team combined transmission electron microscopy with nanoscale manipulation of microfabricated metal needles inside the microscope. The researchers then measured the electrical properties of the SEI layer formed on either a copper or lithium metal with four different types of electrolytes.
The group’s measurements revealed that as voltage increases in the battery, the SEI layer in all cases leaks electrons, making it semi-conductive.
Findings suggest carbon-containing molecules leak electrons, reducing battery life
Once they had recorded this semiconductor-like behavior, which had never been directly observed previously, they wanted to understand which components of the chemically complex SEI are responsible for the electron leakage.
“We found that the carbon-containing organic components of the SEI layer are prone to leaking electrons,” Xu said.
The researchers concluded that minimizing the organic components in SEI would enable the batteries to have longer useful life.
“Even slight variations of the rate of conduction through the SEI can result in dramatic differences in efficiency and battery cycling stability,” Wang added.
***
It will take a while for the lessons this research offers to saturate the battery industry and there will be some time involved for battery designers to research and adapt electrolytes to optimize the battery performance and lifetime.
But better batteries are coming. When cycle lifetimes are extended and capacity looses are minimized our products will have more value and give better longer service lives.
This is welcome research, indeed.
The post Research Explores How Rechargeable Batteries Degrade first appeared on New Energy and Fuel.
Source: https://newenergyandfuel.com/http:/newenergyandfuel/com/2023/11/16/research-explores-how-rechargeable-batteries-degrade/?utm_source=rss&utm_medium=rss&utm_campaign=research-explores-how-rechargeable-batteries-degrade
Anyone can join.
Anyone can contribute.
Anyone can become informed about their world.
"United We Stand" Click Here To Create Your Personal Citizen Journalist Account Today, Be Sure To Invite Your Friends.
Humic & Fulvic Liquid Trace Mineral Complex
HerbAnomic’s Humic and Fulvic Liquid Trace Mineral Complex is a revolutionary New Humic and Fulvic Acid Complex designed to support your body at the cellular level. Our product has been thoroughly tested by an ISO/IEC Certified Lab for toxins and Heavy metals as well as for trace mineral content. We KNOW we have NO lead, arsenic, mercury, aluminum etc. in our Formula. This Humic & Fulvic Liquid Trace Mineral complex has high trace levels of naturally occurring Humic and Fulvic Acids as well as high trace levels of Zinc, Iron, Magnesium, Molybdenum, Potassium and more. There is a wide range of up to 70 trace minerals which occur naturally in our Complex at varying levels. We Choose to list the 8 substances which occur in higher trace levels on our supplement panel. We don’t claim a high number of minerals as other Humic and Fulvic Supplements do and leave you to guess which elements you’ll be getting. Order Your Humic Fulvic for Your Family by Clicking on this Link , or the Banner Below.
Our Formula is an exceptional value compared to other Humic Fulvic Minerals because...
It’s OXYGENATED
It Always Tests at 9.5+ pH
Preservative and Chemical Free
Allergen Free
Comes From a Pure, Unpolluted, Organic Source
Is an Excellent Source for Trace Minerals
Is From Whole, Prehisoric Plant Based Origin Material With Ionic Minerals and Constituents
Highly Conductive/Full of Extra Electrons
Is a Full Spectrum Complex
Our Humic and Fulvic Liquid Trace Mineral Complex has Minerals, Amino Acids, Poly Electrolytes, Phytochemicals, Polyphenols, Bioflavonoids and Trace Vitamins included with the Humic and Fulvic Acid. Our Source material is high in these constituents, where other manufacturers use inferior materials.
Try Our Humic and Fulvic Liquid Trace Mineral Complex today. Order Yours Today by Following This Link.
Just guessing that the specimen holder being inserted into the high vacuum column of the high resolution electron microscope has a special stage capable of charging and discharging a microscopic section of a battery junction. This allows them to watch the SEI layer change as battery is charged and discharged repeatedly at pico current levels. Didn’t find the linked article too informative.