Noble Dome: A Novel Air-Free Transfer System For Battery Research with Electron Microscopy
Authors: Brogden Valerie , Garman Jeff , Weimholt Steve , Langworthy Kurt 
Published: August 2024

"Noble Dome: A Novel Air-Free Transfer System" introduces an innovative solution for loading air-sensitive samples into SEM/FIB instruments. Traditional loading methods expose samples to atmosphere during transfer, hindering investigations of reactive materials. The presented prototype, Noble Dome, directly attaches to the SEM/FIB, enabling sample transfer in an oxygen-free environment. The device's design and operational process are outlined, including airtight chambers, gas introduction, and modified venting systems. Experimental results demonstrate Noble Dome's effectiveness in preserving sample integrity. Compared to existing solutions, which often pose limitations, Noble Dome offers a practical approach for various research needs.

Imaging and micromanipulation techniques such as Scanning Electron Microscopy (SEM) and Focused Ion Beam (FIB) can reveal critical information about the microstructure and composition of materials. To utilize these techniques, a sample must be loaded into the chamber of the instrument which is then pumped down to low vacuum conditions. In the process of removing a sample from its packaging and mounting it on the SEM/FIB stage, the sample is briefly exposed to atmosphere. This is problematic for researchers who are interested in investigating air sensitive samples or samples for which atmospheric contamination would detract from the investigation. This set of samples includes metals commonly used as battery materials such as lithium and sodium, which are highly reactive with elements in the air such as moisture or oxygen.

We present a prototype for a glove box load lock that addresses this problem directly. This device attaches directly onto the side of a SEM/FIB and allows researchers to remove a sample from packaging and transfer it directly on the stage via an accessory port of the SEM/FIB in an oxygen-free environment and then pump the tool down to vacuum without any atmospheric exposure in the process, eliminating the use of an intermediary shuttle from a separate glove box. We call this device Noble Dome.

In order to test Noble Dome’s ability to protect samples from atmosphere, we imaged and collected EDS spectra on the same location of a lithium metal sample in a pristine state, after sitting in Noble Dome for 30 minutes, and after sitting in atmosphere for 30 minutes.

We note that there was very little change in the surface topography and oxygen counts between the sample in its pristine state and the sample after sitting in Noble Dome for 30 minutes. However, there is a marked increase in surface oxidation and topography after the sample sat in atmosphere for 30 minutes.

Lithium-ion batteries are increasingly prolific in the landscape of modern technology. In order to improve the energy density, life cycle and safety of lithium-ion batteries, researchers require significant amounts of materials characterization pre-assembly, post-assembly and after several charge/discharge cycles. Electron microscopy is crucial for effective materials characterization, which necessitates a solution for loading samples into the vacuum chamber of the microscope without exposing these reactive samples to air.

Other solutions currently on the market for loading air sensitive samples into a SEM/FIB involve manipulating the sample in a glove box which is separate from the instrument, loading the sample into an inert gas transfer shuttle which is closed by remote control, removing the shuttle from the glovebox, loading the shuttle into the SEM/FIB, and then opening the sample again via remote control. These solutions are not ideal because they're very expensive, have a variety of limitations on sample size, stage travel, and signal strength, and are high tech solutions prone to costly malfunction. These drawbacks highlight the demand for a more practical and efficient approach.

The presented prototype, Noble Dome, addresses the challenge of loading air-sensitive samples into SEM/FIB instruments with a practical and innovative approach. The device eliminates the need for an intermediary glove box and inert gas transfer shuttle, allowing direct sample transfer onto the stage in an oxygen-free environment. The results demonstrate Noble Dome's efficacy in preserving sample integrity by minimizing atmospheric exposure, as evidenced by the minimal changes observed in surface topography and composition compared to samples exposed to atmosphere. Noble Dome enables research on reactive samples, used to pursue a carbon-free future.

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