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Cathodes Using Lac Knife's Expanded Graphite Display Improved Conductivity in Lithium-Ion Batteries

Focus Graphite Inc., is pleased to report that independent testing of expanded natural flake graphite from its Lac Knife, Québec Project demonstrate nearly double the electrical conductivity over standard grades of synthetic and natural graphite used in Li-Ion battery cathode applications.

The two-year project, involving the preparation and testing of intercalated*, expanded** and delaminated*** Lac Knife graphite was supervised by Dr. Joseph E. Doninger, Focus' Director of Manufacturing and Technology.

Testing was performed between 2014 and 2016 under three contracts with a highly reputable and recognized international firm, with additional scientific investigations using Ramen microscopy provided by a well-known U.S. university laboratory. The names of the internationally recognized facilities were withheld for commercially competitive reasons.

The project began with the development of a modified ASTM C 611 Four Point Resistivity Tester in 2014 to compare the conductivity of different grades of Lac Knife graphite with competitive graphites followed by the development of processes and equipment for the intercalation, expansion and delamination of Lac Knife graphite for use in Li-Ion and alkaline batteries.

The project concluded in a presentation by Dr. Doninger to the 33rd International Battery Seminar and Exhibition in Fort Lauderdale, Florida on March 23, 2016.

A PDF version of Dr. Doninger's technical presentation entitled "Long Term Cycling Performance and Conductivity Enhancement Characteristics of Lac Knife Flake Graphite from Quebec, Canada" is available here:

Expanded graphite is a form of processed natural crystalline flake, featuring dramatically improved electrical conductivity in electrode matrixes. Delaminated expanded flake is also preferable to conventional air-milled flake and/or premium quality synthetic graphites when higher conductivity properties are desired.

To view Figures 1 and 2, please click the following link:

Due to its added-value benefits, expanded graphite typically commands larger revenue margins due to higher selling prices than the competitive grades of flake and synthetic graphite now being used for this application.

Niche markets that use expanded graphite include: specialty paints and coatings, cathodes of alkaline Zinc/Manganese Dioxide primary batteries, cathodes of zinc-air batteries and negative electrodes of lead-acid batteries.

Dr. Doninger said the test results lead to a number of potentially advantageous conclusions for using Lac Knife graphite in both the anodes and cathodes of Li Ion batteries to enhance overall battery efficiencies, including increased power, higher capacity, longer battery life and increased utilization of cathode active materials.

Current commercial pricing for these purified grades of synthetic and expanded flake graphite, said Dr. Doninger, varies from producer to producer, within a range of US $14,000 per metric tonne to upwards of US $30,000 per MT. The higher end of the price range is for a premium grade of synthetic graphite published in the Department of Energy-Argonne National Laboratory Annual Review report for the FreedomCAR Program in 2003.

"These data support our opinion that our value added expanded graphite products could leave Focus Graphite well positioned to compete successfully in international markets," said Dr. Doninger.

"And these high prices for graphites in the cathodes for Li Ion batteries, such as the Focus Lac Knife expanded graphite, creates an opportunity for continuing our research to achieve even greater conductivity enhancement additives," he added.



  1. buyck ruben buyck ruben Belgium says:

    Very good news, the next big step is commercialisation.

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