Studying Graphitisation and Graphite Crystallinity with Raman Spectroscopy
How the Geological Survey of Finland (GTK) used Raman spectroscopy to study graphitisation temperature and measure graphite crystallinity, relevant to battery development.Follow @blue_scientific
Graphite and Battery Development
Natural graphite is a potential anode material for lithium ion batteries. It has a suitable charge/discharge profile, high reversible capacity and is also low cost.
Raman spectroscopy can be used to measure the degree of graphitisation of carbonaceous material. In metamorphic processes, this is independent of pressure but heavily dependent on temperature.
The Geological Survey of Finland used Raman to measure graphite from Rautalampi and Käpysuo in Central Finland. They used the data to calculate graphitisation degrees, which can be used to estimate the metamorphic crystallisation temperatures of carbonaceous material in the rocks.
Flake graphite is the most economically valuable form of graphite. It’s found in regions of high metamorphic grade, such as upper amphibolite and granulite facies terrains. The Rautalampi and Käpysuo areas of Finland are good areas for studying the setting of graphite deposits.
Raman spectra were acquired from 35 petrographic thin sections of graphite-bearing rocks and 6 polished sections of cleaned graphite flotation concentrate. In-situ point measurements were taken, along with detailed studies of the textural relationships between graphite flakes and the surrounding mineral matrix.
Alongside Raman spectroscopy, the study also involved other complementary techniques: optical microscopy, SEM (Scanning Electron Microscopy ), XRD (X-ray Diffraction) and XRF (X-ray Fluorescence).
To see the conclusions and full details of the experiments, take a look at the blog post on the Geological Survey of Finland’s website.
About the Geological Survey of Finland
The Geological Survey of Finland (also known as GTK) is a leading European competence centre for the assessment and sustainable use of geological resources. They work to create solutions leading to new technologies and business areas and promote sustainable growth. GTK is an expert organisation under the Finland’s Ministry of Economic Affairs and Employment.
Raman Spectroscopy in Geology
Raman spectroscopy can be used in various areas of geology and geoscience:
- Identify minerals and their polymorphic forms
- Identify and differentiate organic and inorganic materials
- Particle size and distribution in thin sections and polished blocks
- Image and identify inclusions within transparent materials
- Study samples in modified environments, eg high pressure
- Characterise petrochemical samples
There are several advantages to the technique for geologists:
- Little or no sample preparation
- Complementary to traditional petrographic analysis
- Unambiguous mineral discrimination
- Measure uneven and rough samples, and a variety of sample types
- Combine with microthermometric techniques, SEM, high pressure and temperature cells
The Renishaw InVia is a research-grade confocal Raman microscope, ideal for geological research.
- Powerful, reliable and easy to use
- Automate common tasks to save time
- Accessories to tailor the system for your applications
- Easily combines with SEM
Blue Scientific is the official distributor of Renishaw Raman in the Nordic region (Denmark, Sweden, Finland, Norway, Iceland). We’re available to provide quotes and answer all your questions – just get in touch: