Posted on 05 Oct 2017
With the rise of electric cars and energy storage, graphite – a mineral made of carbon – is poised to be hot on the commodity market to meet demand for lithium-ion batteries.
A mineral of extremes, graphite is the strongest and stiffest naturally occurring material, while contrastingly soft and lightweight. It’s also heat resistant with a high melting point, similar to that of a diamond. These properties, coupled with high conductivity, make graphite critical for use in batteries.
Positively charged demand
Specifically, graphite is needed for battery anodes, the positively charged electrode through which the current flows. While graphite has been used as a key ingredient in anodes in all kinds of batteries for decades, lithium-ion batteries contain proportionately about double the amount of graphite.
To put this into perspective, there is estimated to be 54kg of graphite in the batteries used in each Tesla Model S (85 kWh).
But, not all graphite is equal.
Graphite comes naturally and abundantly in three different forms: ‘crystal’ flake, lump and amorphous. Only high purity (>99.9 per cent) graphite flake is capable of producing the level of electrical conductivity needed to be considered ‘battery-grade’.
About one million tonnes of the mineral is sold annually worldwide. Most of the world’s graphite supply comes from China and Brazil, so a lot of work is going into diversifying the sources of graphite to meet the increasing demand predicted for the future.
Companies seeking to get a competitive edge in this market, are finding ways to improve their production processes so that they can recover more graphite flake, at the highest level of purity possible.
Importance of understanding how graphite forms
Graphite is a metamorphic mineral that has undergone transformation deep underground as a result of heat, pressure and flowing fluid. Graphite flake crystals grow with increasing temperature – upwards of 750 degrees Celsius – as organic matter such as dead bacteria or plants in younger rocks is “cooked up” and converted to graphite.
To read the full article, go to CSIRO Scope