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Photoelectron Spectroscopy Analysis Reveals Insights into Solid-State Battery Degradation
Context: Researchers from HZB and Justus-Liebig-Universität, Giessen, have developed a new method using photoelectron spectroscopy at BESSY II to monitor electrochemical reactions in solid-state batteries, as reported in ACS Energy Letters.
- This approach aims to enhance battery materials and design by providing detailed insights into operational processes.
 Photoelectron Spectroscopy
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Key Highlights
- A team has devised a novel method to examine electrochemical reactions occurring at the interface between a solid electrolyte and electrode with exceptional temporal resolution.
- They investigated samples of the solid electrolyte Li6PS5Cl, recognised as a leading candidate for solid-state batteries due to its high ionic conductivity.
- They utilised an ultra-thin layer of nickel, approximately 30 atomic layers thick or 6 nanometers, as the working electrode.
- On the opposite side of the Li6PS5Cl pellet, a film of lithium was applied to function as the counter electrode.
- Hard X-ray photoelectron spectroscopy (HAXPES) was employed to monitor reactions at the interface in real-time to observe the formation of an interlayer (SEI) and analyse the chemical evolution during battery operation.
- The study revealed that decomposition reactions at the interface were only partially reversible, contributing to reduced battery longevity.
Challenge: Solid-state batteries use a solid ion conductor between the battery electrodes, allowing lithium ions to move during charging and discharging.
- Unfortunately, decomposition products and interphases form at the interfaces between the electrolyte and the electrode.
- These hinder lithium ion transport and lead to active lithium consumption, resulting in decreased battery capacity over charge cycles.
About Solid-state batteries
- A solid-state battery is essentially battery technology that uses a solid electrolyte instead of liquid electrolytes which are instead behind lithium-ion technology.
- They are safer because they are less susceptible to fires.
- They can be charged more quickly.
- They are more energy dense which means they can store more energy in a smaller and lighter package.
- Their limited lifespan remains a challenge.
Implications and Future Directions: By understanding these processes, researchers can improve battery materials and design. The findings pave the way for longer-lasting, more efficient solid-state batteries.
The lithium-ion batteries that we rely on in our phones, laptops and electric cars have a liquid electrolyte, through which ions flow in one direction to charge the battery and the other direction when it is being drained.
