Evolution Energy Minerals (ASX: EV1) has achieved exceptional electrochemical performance in the preliminary results of long-term battery cycling undertaken by the company’s US technology partner.
This is the latest stage in the testwork process that has already demonstrated that Chilalo fines have very low levels of Molybdenum and Boron, can be purified to 99.9995% C and when processed into coated spherical graphite, significantly exceeds the specifications of major EV manufacturers.
Short-term electrochemical testing has previously demonstrated that the uncoated Chilalo spherical graphite delivered a reversible capacity of 367.65 mAh/g with an irreversible capacity loss of 9.4%. The surface coated version of the same material preserved the reversible capacity level, demonstrating 367.8 mAh/g, while decreasing irreversible capacity loss to
Short-term electrochemical testing has previously demonstrated that the uncoated Chilalo spherical graphite delivered a reversible capacity of 367.65 mAh/g with an irreversible capacity loss of 9.4%. The surface coated version of the same material preserved the reversible capacity level, demonstrating 367.8 mAh/g, while decreasing irreversible capacity loss to <7%3.
In this current testwork stage, the uncoated and coated spherical graphites were tested in a cell design engineered for long-term cycling. The testing, which seeks to verify whether the reversible capacity holds from cycle to cycle, is continuing. Evaluation will gauge the degradation of electrochemical performance as a function of elapsed cycle number.
Cycling is performed in CR2016 coin cells, a generally accepted test vehicle for pre-qualifying graphite for use in lithium-ion battery anodes. Cycling is performed at a C/10 rate, meaning that it takes ten hours to charge the cell and the same to discharge. Therefore, one full cycle lasts approximately one day. As cycling just recently started, the company is pleased to report the performance of the first twenty cycles, with more updates to follow.
Phil Hoskins, Managing Director of Evolution, commented, “We are extremely pleased to have started our long-term battery cycle testing program for Chilalo’s coated spherical graphite,” Managing Director, Phil Hoskins, said
“Tests use industry standard CR2016 battery cells, and the results we are seeing to date are very encouraging.
“The surface coated graphite grade that is being tested has a mean particle size of 25 microns, which meets the specifications of at least one leading electric vehicle manufacturer and at least one world-class battery technology provider for lithium-ion cells used in utility-scale energy storage. We will work with these companies as intended offtake partners in the future and will be updating the market as more test data becomes available.”
Next steps
Cycling tests will continue to be performed until 100 cycles have been completed, over a period of two to three months. At this point, long-term cycling performance can be extrapolated.
Sufficient data has already been collected from the commercial verification program undertaken by the Company’s US technology partner to commence qualification initiatives of coated battery anode materials with targeted battery manufacturers.
Testwork is ongoing on the purified, non-spherical by-product that did not qualify as usable spheres for battery anode materials, in order to determine suitability for use as a high-value conductivity enhancement in alkaline battery cathodes.
Achieving a high-value commercial application of the non-spherical by-product would substantially improve the economics of the potential downstream battery anode materials plant.
