The Poseidon Select Liquid Microscopy Cell – The Most Flexible Liquid Cell on the Market

The Poseidon Select Liquid Electron Microscopy system from Protochip​ is the most flexible liquid cell commercially available. The system is configurable and expandable with Heating and Electrochemistry packages designed for varied research interests.

Poseidon Select is considered to be the only liquid microscopy holder that is actually EDS compatible. This in situ liquid system is the safest available on the market and it has been completely evaluated and approved by electron microscope manufacturers. Poseidon Select offers a wide range of liquid microscopy E-chips, including ultra-thin <150 nm liquid layers for high-resolution imaging.

The Poseidon Select Liquid Microscopy Advantage

Electrochemistry Package - The Poseidon Electrochemistry package adds the capability to perform true in situ quantitative electrochemistry and is available as an option to the Poseidon Select system. The Electrochemistry package has been designed to resolve the small currents expected in a miniature cell while simultaneously maintaining imaging and analytical data collection.

Liquid Heating Package - The Poseidon Heating package adds the ability to directly heat liquids within the TEM holder and is available as an option to the Poseidon Select system. The temperature is monitored through the Clarity software package, which provides closed-loop control to guarantee accuracy and stability.

EDS Analysis - The Poseidon Select has a unique design that allows, for the very first time, true EDS elemental analysis within the TEM. A highly efficient design provides a large line-of-sight and angle from the sample to the EDS detector, maximizing count rate and minimizing tilt.

The Poseidon Select Key Features

  • A wide range of replaceable E-chips that control liquid thickness from <50 nm to 5 µ
  • Configurable and expandable design with Heating and Electrochemistry packages that can be added based on the area of interest
  • 3-port (mixing) TEM holder with integrated electrodes and a touch-screen controlled syringe pump
  • Patented design capable of attaining the highest-quality EDS results available
  • Easy-to-use, safe method for replacing the interior tubing of a holder
  • Ultra uniform Liquid Heating from RT to 100 °C closed-loop control
  • 3 electrodes (WE,CE, RE) integrated within the tip of the Poseidon Select holder

It is also possible to add the liquid heating package to any Poseidon Select 500 or 510 system.

Poseidon Select Liquid Microscopy Case Study

In Situ Lithium Dendrite Deposition

Combating the formation of lithium dendrites on the electrode surface after repeated charge/discharge cycles is considered to be a major challenge in the development of lithium-ion battery materials. The so-called “dead” lithium no longer participates in ion transport as dendrites form over repeated cycles.

This results in a reduction in battery capacity, while increasing the potential for the formation of a short circuit between the cathode and the anode.

Protochips’ Poseidon Select system was used by researchers to observe the charge/discharge process of lithium-ion batteries in solution using scanning TEM (STEM). A series of real-time STEM images of the working electrode was obtained as the electrochemical potential of the cell was simultaneously cycled from 0 to -4 volts.

At the start of the first cycle, the surface of the platinum working electrode was pristine, and all of the lithium was dissolved in the electrolyte solution. As the battery was charged, lithium was deposited on the working electrode’s surface; surface roughening was observed, as the lithium was not deposited in an even layer.

Discharging of the battery during the first cycle resulted in a reduction in lithium on the electrode surface, but lithium dendrites continued to remain on the surface of the electrode and did not redissolve in the electrolyte.

An increase in the number of charge cycles resulted in an increase in irreversibility of the electrochemical cell, corresponding to the formation of lithium dendrites and “dead” lithium regions visible in the STEM images. Also visible in the CV curves were characteristic peaks at -2 and -2.5 volts, indicating alloying between the platinum electrode and the lithium in the electrolyte.

Researchers used the Poseidon Select system to successfully image the formation of lithium dendrites during battery charge/discharge cycles, while simultaneously collecting electrochemical data using STEM.

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