We can’t accurately predict how long a new EV battery will last, because user driver patterns vary. We can’t accurately determine remaining battery life either, without doing destructive testing. However, scientists at Seoul National University have found a way through. They used entropy which is one of the thermodynamic parameters.
Tracking the Changes in an Electrode Using Entropy
Entropy is very briefly a measure of the lack of thermal energy available for conversion into mechanical work. Therefore, it is the flip side of the amount of thermal energy actually available.
The scientists at School of Chemical and Biological Engineering, and Institute of Chemical Processes at Seoul National University have used entropy to track changes in battery electrodes without destroying their cells. They measured the open voltage at zero current across a range of temperatures. When they graphed the results they could see the entropic change in the slope.
The Big Picture: Entropy and The Arrow of Time
Back to Earth: More Results from Non-Destructive Entropic Testing
The South Korean scientists also gained fresh insights into cation mixing. That’s where metal ions exchange places in the lattice. Importantly, they found the disorder increased when they ‘doped’ the LiCoO2 cathode with nickel. This improved the framework’s stability and lengthened its cycle life.
Using entropy these ways has several advantages over current battery-testing methods. These only measure current, temperature, and voltage, while the new, entropic method tells us about the material structures inside. Batteries are chemistry, the researchers explain. We need this technology to tell us what is happening in there.
Entropy gives us a new, non-destructive way to achieve this without taking the battery apart, destroying the cell and creating waste. Chemistry World suggests it could also be a useful tool when assessing electronic waste. It could also help determine whether spent batteries are up for re-purposing or are due for recycling.
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The Second Law of Thermodynamics
Preview Image: Schematic Diagrams of Phase Transitions
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