Field emission scanning electron microscopy (FE-SEM) is an advanced microscopy technique for analysing surfaces at incredibly high resolutions.
It uses a focussed beam of electrons to generate detailed images, providing insights into the microstructure and composition of various samples.
A field emission scanning electron microscope functions by emitting a fine beam of electrons onto the sample’s surface. The interaction between the electron beam and the specimen generates various signals, such as secondary and backscattered electrons.
These signals are captured to produce high-resolution images, enabling users to visualise surface details at the nanoscale. FE-SEM’s imaging capability, which achieves resolution in the nanometre range, aids in observing minute structural features, surface topography and elemental composition.
This insight can contribute to scientific research, material analysis and quality control applications across industries.
Lithium-ion battery technology relies on the integrity of intricate components. Among these, the diaphragm plays a crucial role as a separator between the positive and negative electrodes, enabling ion transfer and preventing electrical short circuits.
During FE-SEM inspection, the diaphragm’s microstructure, thickness and uniformity are examined. FE-SEM provides high-resolution imaging, enabling the assessment of defects, particle distribution and overall structural integrity. Accurate evaluation of these diaphragm characteristics helps ensure the efficiency, safety and longevity of lithium-ion batteries in different applications, from portable electronics to electric vehicles and energy storage systems.
There are four main steps when using field emission scanning electron microscopes to inspect Lithium-ion battery diaphragms.
1. Sample preparation
Prepare the diaphragm sample for FE-SEM analysis, eliminating contaminants by cleaning and dehydrating the sample. To ensure optimal imaging quality, apply a conductive coating.
2. Parameter optimisation
For precise imaging, adjust the accelerating voltage, beam current and working distance to align with the diaphragm characteristics. These adjustments allow for accurate electron beam interaction, resulting in detailed and clear image outputs.
3. Image acquisition
The imaging process begins with the FE-SEM scanning the electron beam across the diaphragm’s surface. Parameters such as scan speed, dwell time and signal collection must be controlled to ensure comprehensive coverage and achieve high-resolution imaging.
4. Interpretation and analysis
The captured images can then be used to evaluate the diaphragm sample, allowing examination of its surface features, identification of flaws, measurement of dimensions and elemental analysis using tools like X-ray spectroscopy (XRS). These analyses provide detailed insights into the diaphragm’s structure, guiding further examination or adjustment.
Li-ion diaphragm inspection is important for various sectors due to its role in ensuring battery efficiency and safety, impacting industries ranging from biological sciences to automotive and aerospace technologies.
Biological sciences
Diaphragm inspection profoundly influences biological research and medical technology reliant on lithium-ion batteries. In medical devices like implantable cardiac defibrillators and pacemakers, where uninterrupted battery performance is critical, meticulous diaphragm assessment ensures sustained power supply. Moreover, in biological sciences, advances in battery-related research — such as battery-powered devices for cellular studies — rely on consistent battery performance ensured by diaphragm inspection.
Electronics and technology
Li-ion diaphragm inspection plays a pivotal role in optimising electronics, particularly in portable devices like smartphones and laptops. By ensuring battery efficiency and reliability, diaphragm assessment enables longer battery life and improved performance. It helps further innovations in portable electronics, influencing the development of more efficient batteries powering next-generation devices, including wearables and IoT devices.
Materials science and manufacturing
In materials science applications, diaphragm assessment contributes to maintaining battery integrity in high-stress environments such as the aerospace and automotive sectors. Additionally, it aids in optimising battery manufacturing techniques, ensuring consistent quality and performance in diverse applications like energy storage systems and industrial equipment.
Energy and the Environment
Diaphragm inspection is pivotal for ensuring energy efficiency and sustainability in various applications such as renewable energy storage systems and grid stabilisation. By maintaining battery reliability and performance, it enables the transition towards cleaner energy sources. Moreover, it ensures that batteries in electric vehicles and renewable energy storage systems maintain optimal efficiency, helping to reduce carbon emissions.
Healthcare and medical
In healthcare, Li-ion diaphragm inspection ensures the reliability and efficiency of batteries in critical medical devices like insulin pumps, portable diagnostic equipment and implantable medical devices. It supports the development of reliable and safe medical technologies, ensuring uninterrupted power supply in life-saving devices and enabling advancements in healthcare technology.
Automotive and aerospace
Diaphragm inspection significantly impacts the safety and efficiency of lithium-ion batteries in electric vehicles, aircraft and spacecraft. By ensuring the reliability and longevity of batteries, it supports the shift towards vehicle electrification, driving advancements in lithium-ion battery technology crucial for increased range, reduced charging times and enhanced safety in automotive and aerospace applications.
When selecting FE-SEM equipment, key considerations include the resolution, imaging capabilities, automation, space requirements and relevance to laboratory needs. SciMed currently offers two models: the CIQTEK SEM5000, with exceptional resolution and diverse applications, and the CIQTEK SEM4000, providing versatile imaging modes and reliable performance.
The CIQTEK SEM5000 features remarkable resolution across various accelerating voltages, boasting a magnification range extending up to 2,500,000x. Its compact design caters to space-limited laboratories or industries. Additionally, this model offers a suite of detectors and tools, making it suitable for in-depth and comprehensive analysis.
The CIQTEK SEM4000 shows adaptability, featuring a higher minimum accelerating voltage and optional vacuum capability, catering to a range of applications.
Choosing between these models requires consideration of research objectives, applications and budget constraints. For guidance in selecting the most suitable model, consulting with an expert can provide insight, and SciMed can assist in aligning the instrumentation with the research objectives.
Interpreting FE-SEM results is a meticulous process involving distinct analytical steps for a comprehensive evaluation of sample characteristics.
Scrutinise surface details, examine morphology and identify structural features visible in the images.
Conduct precise measurements using specialised software available in the SEM, enabling dimensional assessments and surface roughness analysis.
Employ XRS to identify and analyse elemental composition in the sample.
Evaluate surface topography to understand the sample’s surface characteristics, enabling a comprehensive analysis.
Examine the sample to identify irregularities and anomalies, allowing for the recognition of defects or structural issues.
Surface analysis involves detailed scrutiny of surface details, dimensional measurements and precise surface roughness assessments using specialised software. Employing these quantitative measurements allows for precise evaluation, facilitating comparisons with research objectives and standards.
Utilising XRF data to identify and analyse elemental composition in the sample is fundamental to understanding the sample’s composition.
Utilise acquired data to make informed modifications, improving diaphragm quality and performance. Leverage these insights to refine design and production processes by tailoring manufacturing techniques, adjusting material compositions and fortifying quality control measures for heightened efficiency and reliability.
For further improvements in diaphragm inspection and development, connect with the SciMed team to discover the capabilities of the SEM4000 and SEM5000 for your research and industrial applications.
