Improving Battery Material Quality Control Through Accurate True Density Measurement

How the AMI DensiPyc 1000 supports the characterisation of cathode and anode materials

As the demand for high-performance batteries continues to grow, manufacturers face increasing pressure to improve material consistency, optimise production processes and maintain stringent quality standards.

But how accurately are you measuring the physical properties of your battery materials?

Particle size, porosity and surface area are widely recognised as important parameters in battery development. However, true density is another critical property that can provide valuable insight into material quality, structural characteristics and manufacturing consistency.

For manufacturers of lithium-ion batteries, even relatively small variations in material properties can influence electrode preparation, packing density and ultimately battery performance.

In this article, we explore the importance of true density measurement in battery materials, the advantages of helium pycnometry and how the AMI DensiPyc 1000 delivers highly repeatable measurements across a range of cathode and anode materials.

Why is true density important in battery manufacturing?

True density, also known as skeletal density, describes the mass of a material divided by the volume of its solid framework.

Unlike bulk density, which includes the spaces between particles, true density excludes open pores that are accessible to the measurement gas. Closed pores remain included in the measured skeletal volume.

Understanding this property is important because it provides information about the intrinsic structure of a material.

In battery manufacturing, accurate true density measurements can support several important processes:

• Electrode optimisation: True density helps establish the theoretical density limits of electrode materials, supporting calculations for electrode compaction and volumetric energy density.

• Material consistency: Variations in true density between batches can indicate changes in raw materials, synthesis conditions or material structure.

• Process monitoring: Regular measurements help identify changes in manufacturing processes before they lead to wider quality issues.

• Quality control: True density measurements provide an additional parameter for assessing incoming raw materials and monitoring production consistency.

For example, graphite used in lithium-ion battery anodes has an ideal crystalline density of approximately 2.26 g/cm³. Commercial graphite materials can exhibit lower values depending on their structure and degree of graphitisation.

Monitoring these values can help manufacturers identify differences between material batches and assess the consistency of their production processes.

Helium pycnometry: A reliable method for measuring true density

One of the most widely used techniques for determining true density is gas pycnometry.

This method uses the gas displacement principle, applying Boyle’s law to determine the volume occupied by a solid sample.

Helium is particularly suitable for this application because of its very small molecular size, chemical inertness and low tendency to adsorb onto material surfaces under ambient measurement conditions.

With a kinetic diameter of approximately 0.26 nm, helium can penetrate many open pores within battery materials, allowing the instrument to determine the volume of the solid framework more accurately.

The measurement process works by introducing helium into a chamber containing the sample and allowing it to expand into a known reference volume. The resulting pressure change is used to calculate the sample’s skeletal volume and, when combined with its mass, its true density.

This makes helium pycnometry particularly useful for characterising complex materials, including graphite, silicon-carbon composites and porous carbon.

However, achieving reliable results requires more than simply applying the measurement principle. Temperature stability, effective sealing, appropriate reference volumes and consistent sample preparation all play important roles.

Introducing the AMI DensiPyc 1000

The AMI DensiPyc 1000 is an automated gas pycnometer designed to deliver accurate and repeatable true density measurements for research and quality control applications.

Its design incorporates several features intended to minimise operator influence and improve measurement consistency.

Automated sample chamber sealing

Manual sample chamber sealing can introduce variations between operators, potentially affecting measurement repeatability.

The DensiPyc 1000 incorporates an automated mechanical sealing system that applies consistent sealing force and positioning for each measurement.

This helps reduce operator-dependent variation and supports more consistent results, particularly in laboratories carrying out routine quality control testing.

Intelligent reference volume management

Selecting the appropriate reference volume is important for accurate gas pycnometry measurements.

The DensiPyc 1000 incorporates multiple internal reference volumes, with software that automatically selects the most appropriate configuration based on the installed sample cell.

This helps minimise dead volume effects and supports accurate measurements across different sample sizes.

Optional integrated weighing

Selected DensiPyc 1000 configurations offer an integrated microbalance, with a capacity of up to 500 g and a resolution of 0.001 g.

This allows samples to be weighed directly within the instrument, reducing the need for separate weighing steps.

By simplifying sample handling, the integrated balance can help improve workflow efficiency, minimise handling errors and support measurement traceability.

Optional vacuum degassing

Sample preparation can have a significant influence on measurement results, particularly when working with moisture-sensitive materials.

The optional vacuum degassing configuration provides integrated vacuum conditioning down to 10 kPa, helping remove residual gases and moisture before analysis.

This is particularly useful when characterising freshly prepared or moisture-sensitive battery materials.

Temperature control

Temperature fluctuations can influence gas pressure and consequently affect volumetric measurements.

The DensiPyc 1000 TC configuration offers Peltier-controlled temperature regulation from 4°C to 60°C, helping maintain stable measurement conditions.

This can be particularly beneficial for laboratories requiring consistent results across different environmental conditions.

Experimental study: Measuring the true density of battery materials

To demonstrate the capabilities of the DensiPyc 1000, AMI Instruments conducted an application study examining five representative battery materials.

The study included two cathode materials and three anode materials:

Cathode materials:

• Iron phosphate (FePO₄)

• Lithium iron phosphate (LiFePO₄)

Anode materials:

• Graphite

• Silicon-carbon composite

• Porous carbon

Measurements were carried out using a 50 cm³ sample cup with a lid, filled to approximately 80% of its volume.

Ultra-high-purity helium (99.999%) was used as the displacement gas, with all measurements performed at 25°C.

Each sample underwent three consecutive measurements to assess repeatability.

Importantly, the study did not apply additional sample pretreatment, such as drying, before measurement. This provided an insight into the instrument’s performance under conditions intended to reflect routine incoming material inspection.

Results: Cathode material analysis

Cathode materials play a fundamental role in determining battery capacity, energy density and electrochemical performance.

Understanding their physical characteristics is therefore important during both material development and production quality control.

The DensiPyc 1000 was used to measure the true density of iron phosphate and lithium iron phosphate.

The results were:

Both materials demonstrated excellent measurement repeatability, with relative standard deviations below 0.1%.

LiFePO₄ achieved an RSD of just 0.0223%, demonstrating highly consistent measurements across the three consecutive tests.

For battery manufacturers, this level of repeatability is valuable when comparing material batches, investigating changes in synthesis conditions and monitoring the consistency of incoming raw materials.

Reliable density measurements can also contribute to a better understanding of electrode compaction and material utilisation.

Results: Anode material analysis

Anode materials also require careful characterisation to help maintain consistent battery performance.

Graphite remains one of the most widely used anode materials, while silicon-carbon composites are attracting considerable interest because of their potential to increase energy storage capacity.

Porous carbon is also used in various battery-related applications, where its internal structure and pore characteristics can influence material behaviour.

The DensiPyc 1000 was used to analyse all three materials.

The results were:

All three materials achieved repeatability below 0.1% RSD.

Graphite: Monitoring material consistency

Graphite achieved an average true density of 2.2308 g/cm³, with an RSD of just 0.028%.

This result is consistent with the expected range for commercially graphitised materials, which can differ from the ideal crystalline graphite density of approximately 2.26 g/cm³.

Regular monitoring of graphite density can help identify variations in graphitisation, raw material sources and manufacturing conditions.

Silicon-carbon composites: Supporting advanced anode development

Silicon-carbon composites achieved an average true density of 2.0131 g/cm³, with an RSD of 0.059%.

As manufacturers continue to investigate silicon-containing anode materials, reliable physical characterisation becomes increasingly important.

True density measurements provide an additional way to monitor material consistency and investigate changes in composition or manufacturing processes.

Porous carbon: Understanding measurement variability

Porous carbon produced an average true density of 2.2362 g/cm³, with an RSD of 0.097%.

Although this was the highest variability recorded in the study, the result remained below the 0.1% repeatability threshold used in the application study.

The slightly higher variation highlights an important consideration when analysing microporous materials.

Although helium can penetrate very small pores, gas diffusion into complex microporous structures may take longer to reach equilibrium. The extensive internal surface area can also influence the measurement process.

For these materials, extending the pressure equilibration time and increasing the number of measurement cycles can help improve consistency.

This demonstrates why understanding the characteristics of the sample is just as important as selecting the appropriate analytical instrument.

What do these results mean for battery manufacturers?

The results demonstrate the potential of automated helium pycnometry as a valuable tool for battery material characterisation.

For laboratories working with cathode and anode materials, accurate true density measurements can support several areas of manufacturing and research.

1. Incoming material inspection

Differences in raw material properties can affect subsequent manufacturing processes.

Routine density measurements provide an additional quality control parameter when assessing incoming graphite, lithium iron phosphate and other battery materials.

2. Monitoring manufacturing consistency

Establishing a baseline for true density allows manufacturers to monitor variations between production batches.

Changes in measured values may highlight differences in synthesis conditions, raw material quality or material structure, allowing further investigation before these variations affect downstream processes.

3. Optimising electrode production

Accurate density data can support calculations relating to electrode compaction and volumetric energy density.

Understanding the physical properties of the starting materials helps manufacturers make more informed decisions when optimising electrode formulations and processing conditions.

4. Supporting research and development

As battery technologies evolve, researchers are continually investigating new electrode compositions and advanced materials.

Reliable true density measurements provide useful information when comparing different formulations, assessing material modifications and investigating the relationship between material structure and performance.

Why measurement repeatability matters

When selecting an analytical instrument, it is important to look beyond its headline accuracy specification.

Repeatability is particularly important in quality control environments, where laboratories need confidence that repeated measurements will produce consistent results.

The AMI DensiPyc 1000 application study demonstrated RSD values below 0.1% across all five battery materials tested.

This provides encouraging evidence of its measurement stability across a range of different material types, including microporous samples.

Combined with automated sealing, intelligent reference volume selection and optional integrated weighing and vacuum degassing, the DensiPyc 1000 offers a streamlined approach to true density measurement.

Conclusion: Improving confidence in battery material characterisation

As battery manufacturing continues to develop, the need for reliable material characterisation becomes increasingly important.

True density provides valuable information about the physical structure of cathode and anode materials, helping manufacturers monitor raw material consistency, investigate process variations and support electrode optimisation.

The AMI DensiPyc 1000 demonstrated excellent repeatability across five representative battery materials, achieving RSD values below 0.1% in the published application study.

For laboratories involved in battery research, material development and manufacturing quality control, automated helium pycnometry offers a reliable method for obtaining important density data.

At Meritics Ltd, we supply advanced analytical instrumentation to support material characterisation across a wide range of industries.

If you are working with battery materials and want to improve your understanding of true density, speak to our team about the AMI DensiPyc 1000.

Contact our application specialists at sales@meritics.com to discuss your requirements and find out how we can help.

#BatteryMaterials #BatteryManufacturing #LithiumIonBatteries #TrueDensity #GasPycnometry #MaterialCharacterisation #QualityControl #EnergyStorage #AMIDensiPyc1000 #Meritics

Particle Shape Analysis for Powders

Can You Analyse the Particle Shape of Dry Powders?

We are regularly asked whether there is a solution for analysing the particle shape of dry powders.

While many dynamic image analysers require particles to be suspended in a liquid, analysing powders in their natural dry state has traditionally been much more challenging.

Until now.

Introducing the BeVision D3 Dry Powder Particle Size & Shape Analyser

The BeVision D3 Series is a fully automated particle size and shape analyser based on advanced Dynamic Image Analysis (DIA) technology. Designed specifically for dry powders, it delivers rapid, highly accurate particle size and morphology measurements for both research and quality control applications.

How Much of Your Sample Are You Really Seeing?

Traditional sieve analysis classifies particles by size—but tells you very little about their shape.

The BeVision D3 reveals far more.

Its intelligent dry dispersion system features automatic funnel height adjustment, intelligent feed rate control and optimised guide slot spacing to ensure consistent, repeatable particle dispersion.

Powered by high-speed dynamic imaging, the BeVision D3 captures high-resolution images of every particle across an exceptionally wide size range.

A dual-camera system provides complete particle coverage in a single measurement:

• Wide-field camera for larger particles
• High-magnification zoom camera for fine particles

This enables comprehensive particle size distribution and morphology analysis without compromising speed or accuracy.

Understand More Than Just Particle Size

The powerful analysis software automatically identifies and classifies complex particle morphologies, including:

• Rod-shaped particles
• Needle-shaped particles
• Near-spherical particles
• Irregular particles

These insights are invaluable for applications across:

• Plastics
• Additive manufacturing
• Agriculture
• Abrasives
• Petroleum catalysts
• Chemicals and advanced materials

After analysis, your sample is fully recovered in the integrated collection tray.

Faster Than Traditional Sieve Analysis

The BeVision D3 delivers complete particle size and shape results in as little as 1–3 minutes, compared with approximately 30 minutes for conventional sieve analysis.

A built-in correlation tool allows you to compare results directly with sieve data while providing significantly richer information through high-resolution particle imaging and morphology analysis.

Visualise Every Particle

The intuitive software enables you to explore your data with ease, including:

• Particle size distributions
• Particle shape distributions
• Particle population statistics
• Customisable reports
• A searchable image gallery showing every analysed particle

See exactly what your sample contains—not just how big the particles are.

Your Solution for Dry Powder Particle Shape Analysis

BeVision D3 Series

Introducing the DeepSizer 300

DeepSizer 300: Intelligent Sediment Monitoring, Now Available in the UK from Meritics Ltd

Meritics Ltd is proud to announce the arrival of the Bettersize DeepSizer 300, a next-generation submersible particle size analyzer designed for intelligent, real-time sediment monitoring in natural water environments.

Engineered for precision and durability, the DeepSizer 300 measures particle concentration (0.001–100 g/L) and particle size (0.1–2000 μm) directly in situ—whether in rivers, lakes, estuaries, or coastal waters. With its robust design and intelligent data processing, it delivers continuous, high-resolution insights into sediment transport, water quality, and environmental change.

At the heart of the DeepSizer 300 are six core technologies, including two patented innovations—Differential Path Technology and Adaptive Path Technology—that ensure high accuracy and exceptional adaptability to varying turbidity levels and environmental conditions. Its 80-detector array, covering scattering angles from 0.0163° to 42°, captures fine details of particle dynamics with outstanding precision.

The instrument also records depth, temperature, and conductivity, providing a more complete picture of aquatic environments. Its automatic optical window cleaning system ensures consistent, maintenance-free operation by removing deposits and contaminants that can compromise data quality.

Designed for flexibility, the DeepSizer 300 supports **three transmission modes—wired, wireless, and offline—**allowing seamless integration into a variety of monitoring setups, from remote field stations to mobile research platforms.

For researchers, environmental agencies, and water quality professionals, the DeepSizer 300 represents a powerful new tool for understanding sediment behaviour and supporting sustainable water resource management.

Now available in the UK exclusively from Meritics Ltd, the DeepSizer 300 continues Bettersize’s legacy of combining scientific innovation with practical design—helping users measure with confidence, even in the most challenging environments.

Bettersizer S3+ aids Additive Manufacturing processes

What does the Bettersizer S3+ offer?

The Bettersize Instruments Bettersizer S3+ plays a crucial role in Additive Manufacturing (AM) by providing precise particle size and shape analysis of metal, polymer, and ceramic powders. AM processes, such as Selective Laser Sintering (SLS), Electron Beam Melting (EBM), and Binder Jetting, rely on powders with well-defined particle size distributions (PSD) and morphology to ensure consistent layer deposition, packing density, and flowability.

Importance of using the right technology

The Bettersizer S3+ integrates laser diffraction and dynamic image analysis, enabling high-resolution measurement of particle size (0.01–3500 µm) and direct visualisation of shape characteristics. The laser diffraction technique provides a rapid and accurate PSD analysis, which is essential for optimizing powder bed density and minimising defects like porosity or poor fusion. The dynamic image analysis detects particle sphericity, aspect ratio, and agglomeration, which influence powder flow and print quality.

By ensuring tight control over powder quality, the Bettersizer S3+ helps manufacturers optimise material performance, mechanical properties, and process efficiency. Real-time data enables rapid adjustments in powder selection, recycling strategies, and supplier quality control, reducing costs and improving final part integrity. This makes the Bettersizer S3+ an essential tool for ensuring repeatability and reliability in industrial AM applications.

Find out more…

The most versatile particle characterisation instrument: Bettersizer 2600

Meritics Ltd offers the Bettersizer 2600, a cutting-edge particle size analyser that utilises proven Laser Diffraction Technology to measure particle sizes ranging from 0.02 to 2,600 μm. Its modular design allows for flexible functionality, with the option to incorporate a dynamic imaging module. This combination of laser and imaging extends the measurement range up to 3,500 μm and enables comprehensive particle size and shape analysis. Additionally, the system supports both dry and wet dispersion methods, making it suitable for a broad spectrum of measurement applications.

Features and Benefits:
• Wide particle size range: 0.02 to 2,600 μm (wet dispersion), 0.1 to 2,600 μm (dry dispersion), and 2.0 to 3,500 μm (dynamic imaging)
• Dual optical system: Laser Diffraction and Dynamic Imaging for comprehensive analysis
• Advanced laser diffraction: Incorporates both Fourier and inverse Fourier designs for enhanced precision
• 92 distributed spherical detectors: Captures light signals from 0.016° to 165° for accurate measurements
• Auto-alignment: Automatically aligns the laser diffraction system, removing the need for manual adjustments
• Modular dual-camera imaging: Provides 24 detailed particle parameters for in-depth analysis
• Interchangeable dispersion units: Supports seamless switching between dry and wet dispersion methods
• User-friendly software: Designed for efficiency and ease of operation
• Regulatory compliance: Meets ISO 13320, 21 CFR Part 11, USP <429>, and ISO 13322-2 standards

Interested? Contact Meritics today to arrange a demo – 01582 704807 info@meritics.com www.meritics.com

Low field NMR Instrument for Complex Nanoparticle Suspension Characterisation

The Mageleka RelaxoMeter is ideal for routine analysis of complex multi-component nanoparticle solid-liquid, liquid-liquid formulations using non-invasive technology based on NMR proton relaxation.

In every industrial application a knowledge and understanding of the molecular structure and dynamics at the particle-liquid interface is critical to improving or optimising suspension and emulsion product performance at every stage from initial formulation to final manufacture. The RelaxoMeter provides direct information about the extent and nature of any particle-liquid interface of suspensions and emulsions in a matter of minutes.

Measurements are simple and easy, the sample is placed into a standard NMR tube and then inserted into the MagnoPod©, the test sequence is then initiated and the result reported in under 2 minutes.  An exceptionally wide concentration range of 0.01% to 90+% with small sample size of 0.1mL or less and with little or no sample preparation, the Magnometer is perfect for routine analysis of particles suspended in solvents and melts regardless of shape and size.  With no prior NMR experience required, the Magnometer is suitable for chemists, technicians or plant workers. The separate magnet assembly allows for remote or glove box operation, an optional programmable temperature-controlled unit is idea for environments where temperature stability is required. The technique is non-destructive so perfect for long term studies. The range also includes the SedimentoMeter for sedimentation studies and the RelaxFlow for flow through experiments.

Applications include batch-to-batch reproducibility in manufactruing, formulation development, kinetic processes, surfactant and competitive surfactant adsorption, aggregation, flocculation, sedimentation studies, presence of para – ferro-magnetic impurities, oxygen and water content of solvents, polymer and solvent viscosity and additive studies.

Industries served include catalyst, pharmaceutical and personal health care providers, paints. Pigments and coatings, ceramics, refractories, agrochemicals, cosmetics, batteries, electronics, nano medicine and graphene/graphene oxides.

Fibre Analysis with Flow Imaging Microscopy

Introduction

Geometry can play a crucial role in the performance of fibres in
different applications. Shape factors that influence performance
include length (i.e. size of the longest dimension of the fibre), width
(i.e. size of the shortest dimension), and curl. Despite the importance
of fibre geometry, many conventional particle sizing measurements
struggle to accurately capture the morphology of these particles.
Volumetric-based particle sizing methods such as laser diffraction
and Coulter Counters assume particles exhibit spherical geometry
and only report equivalent spherical diameter (ESD) measurements.
Manual microscopy, the primary method used for measuring fibre
length and width, is low-throughput and labour-intensive to perform.

Flow imaging microscopy (FIM) instruments like FlowCam are an
automated, high-throughput alternative to manual microscopy for
fibre analysis. VisualSpreadsheet® software acquires and analyses
images of fibrils, providing automated measurements of not only
fibre length and width but also fibre straightness and curl from
particle images similar to those obtained via manual microscopy
(Figure 1). As FIM instruments capture fibre images in a flowing
fluid, this technique offers much higher throughput than manual
microscopy. These features make FlowCam an ideal instrument for
rapid, automatic fibre analysis.

Fibre measurements in VisualSpreadsheet

Most particle imaging systems use Feret measurements to determine
the length and width of particles. Feret measurements involve finding
edges on opposite sides of a particle that are parallel to each other
and measuring the distance between these edges. The shortest
Feret measurement is reported as particle width, and the longest
is reported as particle length (Figure 2). These Feret measurements
are recorded as the “Length” and “Width” parameters reported
by VisualSpreadsheet. While these measurements are accurate for
symmetric and straight particles, Feret measurements dramatically
undersize the length and oversize the width of curved particles.

VisualSpreadsheet also records Geodesic measurements of particle
lengths and widths. Geodesic measurements account for the arcing
of particles like fibres, thus providing a more accurate representation
of fibre length and width (Figure 2). In VisualSpreadsheet, these fibre
measurements are reported as geodesic length and geodesic thickness.

Figure 3 shows a comparison between these measurements for a
straight fibre and for a curved fibre. Reported values for length (Feret)
and geodesic length of the straight fibre are relatively similar, as are
those for width (Feret) and geodesic thickness. When these values
are compared for the curved fibre, the length (Feret) measurement
is much lower than the geodesic length measurement, and width is a
much larger value than the geodesic thickness measurement. While
the length (Feret) measures the long-axis distance covered by the
particle, the geodesic length factors the curvature of the particle into
its reported length and is thus more accurate. Similarly, the geodesic
thickness is more accurate as it primarily accounts for the width of the
particle and not the short-axis distance covered by the particle.

Other fibre measurements available in VisualSpreadsheet include
fiber straightness and fibre curl. Fiber straightness is the ratio
of length (Feret) to geodesic length. Higher straightness values
indicate better agreement between the Feret and geodesic length
measurements, corresponding to straighter particle geometry.
Fiber curl is calculated by dividing geodesic length by length (Feret)
and subtracting one. A particle with a fibre curl of zero is perfectly
straight and increasing curl values indicating higher degrees of
curling. Figure 4 shows fibre measurement data for a curved wood
fibre with a relatively high fibre curl value and relatively low fibre
straightness value.

Using fibre measurements to evaluate samples

In applications where fibre morphology is important for quality
control of fibrous materials, VisualSpreadsheet can be used to
build and save custom filters that automatically report counts and
concentrations of particles matching a particular specification. For
example, if fibre straightness is of concern, pre-built filters can
automatically report a percent of fibres that meet or exceed a user defined
fibre straightness threshold.

Figure 5 shows data for custom value filters created for bleached
softwood cellulose microfibrils at a specific stage of the refining
process. For this example, at least 50% of the fibres must have fibre
straightness ≥ 0.75 for a lot to pass quality control. After each lot of
fibres is analysed, the filter bins instantly populate with a percentage
of particles matching the passing criteria, allowing operators to
quickly assess whether a particular lot has passed.

An added benefit of VisualSpreadsheet is the ability to directly
interact with the filter grid and data plots. By selecting the “Pass –
Fibre Straightness 0.75+” filter, particle images that match the filter
will automatically display in the View Window (Figure 6, next page).
These particle images can then be sorted, selected, and/or saved.
Regions of histograms or scatterplots that contain particles matching
the filter will also be highlighted. Data can be easily exported into
Excel or as a PDF document for a seamless reporting and archiving
process.

Conclusion

FlowCam is a powerful analytical tool that expedites and streamlines
fibre analysis. Integrated fibre morphology parameters include
geodesic length, geodesic thickness, fibre straightness, and fiber curl.
Using these measurements, FlowCam provides more accurate and
reliable data than volumetric-based methods and offers a significant
time-savings over manual microscopy. The option of building custom
filters in VisualSpreadsheet allows for instantaneous reporting of
results at the conclusion of sample analysis, saving users time and
effort in assessing fiber quality.