In-situ Electrochemical XRD Analytical Service

Overview

In-situ Electrochemical XRD is used to monitor the crystal structure changes of materials in real-time during electrochemical reactions. It is particularly valuable in the study of lithium-ion and sodium-ion batteries, providing direct experimental evidence for understanding the structural evolution, energy storage mechanisms, and capacity decay mechanisms during complex electrochemical processes.

In-situ XRD operates in two modes:

1. Transmission Mode: X-rays enter from one side of the electrochemical cell, and the diffracted X-rays exit from the other side, where they are detected by a detector. This mode typically requires high-intensity X-ray sources, such as those generated by synchrotron radiation accelerators.
2. Reflection Mode: X-rays enter the electrochemical cell through a window, pass through the material, and exit through the same window, where they are detected. This is currently the most commonly used testing mode.

Applications 

• Lithium-ion Batteries: Focused on the intercalation reactions of lithium ions in materials like Si, Sb, and Ge, as well as the conversion reactions in metal oxides and metal sulfides. These studies help understand structural changes during charge and discharge processes, facilitating battery design optimization.
• Lithium-sulfur Batteries: In-situ XRD is employed to detect phase changes in electrode materials during charge and discharge, playing a key role in understanding the generation process of polysulfides during the reaction.
• Sodium-ion Batteries: In-situ XRD is used to study the structural evolution of cathode and anode materials during electrochemical reactions.

Results Display

Reference: http://doi.org/10.1002/adma.202305190

To gain a deeper and more comprehensive understanding of the sodium-ion insertion and extraction mechanism in CoPS@C@N-CNF, in-situ electrochemical XRD testing was conducted during the first cycle. The in-situ XRD patterns are shown in Figures (e) and (f).

Several prominent peaks related to BeO and Be were detected in the range of 37° to 50°. During discharge from open circuit voltage to approximately 1.0 V, the first intercalation reaction of CoPS began with the insertion of Na⁺ ions, leading to the disappearance of the diffraction peaks of the original CoPS phase. Simultaneously, four weak peaks corresponding to the intermediate phase Na₂CoS₂ (JCPDS # 79-2415) appeared at 16.00°, 26.10°, 33.00°, and 38.30°, matching the crystal planes (110), (121), (211), and (141), respectively.

As more Na⁺ ions were inserted into the electrode, the potential dropped to 0.01 V, representing a fully sodiated state. At this point, the phase generated during the first intercalation reaction disappeared, and new phases appeared, including Na₂S (JCPDS # 47-0178) with crystal planes (400), (500), and (542) at approximately 22.40°, 27.90°, and 37.70°, and metallic Co with the (111) plane at approximately 45.9° (JCPDS # 88-2325). This provided strong evidence for the conversion reaction from Na₂CoS₂ to Na₂S and Co. Additionally, a peak for Na₃P (JCPDS # 74-1164) was observed at around 36.10°, indicating an alloying reaction between P and Na⁺.

Upon charging to around 1.4 V, the peaks corresponding to Co, Na₂S, and Na₃P disappeared, and Na₂CoS₂ reappeared, indicating the expected reversible reaction and dealloying process. However, when further charged to 3.0 V, Na₂CoS₂ peaks at 16.00°, 33.00°, and 38.30° were still detected, suggesting that CoPS could not fully restore its original crystal phase during the first desodiation process, consistent with the reported behavior of CoPSe anodes in SIBs.

Notably, throughout the first cycle, no characteristic reflection signals from phosphorus were detected, likely due to its small crystal size or amorphous nature.

Sample Requirement

A minimum of 200 mg of powder samples is required.

When assembling in-situ batteries, the anode material should be coated onto a stainless steel mesh or Al foil, and the cathode material should be coated onto Al foil. The test data will include peaks from the current collector substrate; therefore, the sample must have a certain degree of crystallinity with strong XRD signals. If the powder sample has poor crystallinity, its diffraction peaks may be overshadowed by those from the substrate. Additionally, the in-situ sample cell is encased by a Be ring, and peaks from Be and BeO are usually strong but do not affect data analysis.

The electrode loading in the in-situ cell needs to reach 3–4 mg or more to enhance signal intensity. It is essential to verify the performance of your material at this loading level in standard coin cells, including its cycling stability and specific capacity.

Note: The listed price is for reference only. Please request a quote for the final pricing.

Analytical Service Minimum order requirement: $250 per order. A $200 handling fee will be applied if order is below $250.

Please contact sales@msesupplies.com for additional information and instructions on our Analytical Services program. Confirmation of the sample(s) requirements, SDS sheets and additional information is needed prior to processing the Analytical Service order. 

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