Alba Mineral Resources Plc announced that GreenRoc Mining Plc regarding the successful results of electrochemical battery test work using graphite from its Amitsoq Graphite Project in southern Greenland, along with an update on its Processing Plant Feasibility Study following a visit to processing plant manufacturers in China last week. To qualify as potential feedstock for the production of active anode material for lithium-ion ("Li") batteries, graphite concentrate must have its performance tested in a battery setup. In autumn 2023, GreenRoc contracted ProGraphite GmbH in Germany to order and oversee an electrochemical test work programme at a well-established battery research centre on graphite extracted in 2022 from the Lower Graphite Layer orebody at Amitsoq.

Amitsoq graphite concentrate was processed into spherical graphite with D50 of 16 µm (average particle size of 16 micrometre) and purified to >99.95% graphite. This material was combined with other components to form a final slurry, which was coated onto a copper foil to form the anode. This anode was then inserted within a newly assembled single, disc-shaped Lithium-based battery cell with a diameter of 10.95 mm.

The battery cell was then subjected to a series of charging and discharging cycles. The results of the programme reported a first discharge specific capacity after battery formation and condition of 369 mAh/g. This is close to the theoretical maximum achievable value of 372mAh/g, which is considered a good result. In subsequent cycles, the charging capacities achieved were also considered good for uncoated spherical graphite.

In tests with a long charging time (3-10 hours), the discharge performance was very good with near 100% Coulombic Efficiency (99.81% +/- 0.06% to 100.09% +/- 0.2%). At a high number of charge/discharge cycles (40-44), the battery maintained a high capacity (363 mAh/g), which suggests good durability, and, after a high charging rate/short charging time (6 minutes) cycle, the performance was still good, showing that no damage occurred to the material at such elevated charging rates. Finally, differential capacity measurements showed staged intercalation of Li-ions both during charging and during discharging, which in turn demonstrates good crystallinity of the Amitsoq graphite anode material.

This is also a positive, sincelong cycle life correlates with stable graphite crystallite size.