Graphite One's STAX excels in battery anode tests

Graphite One Resources Inc. May 20 reported that uncoated spheroidized (rounded) graphite from its Graphite Creek property, located about 37 miles (60 kilometers) north of Nome, Alaska, demonstrated high performance when tested in CR2016 coin cells, batteries typically used in watches and similar devices.

Five coin cells were tested with Graphite Creek material in the anode.

Three of the cells demonstrated a first discharge capacity that approached natural graphite's theoretical maximum of 372 ampere hours per kilogram.

Discharge capacity is a measure of a battery's energy storage capability once first charged.

The first-discharge capacity of the best-performing coin cell, 1203, equaled the theoretical discharge capacity of natural graphite.

Coin cells 1207, 1208 and 1209 showed first-discharge capacities ranging from 369.1 to 370.9 ah/kg, or within 1 percent of the theoretical maximum.

The lowest performing coin cell, 1211, had a first discharge capacity of 361 ah/kg.

Lithium-ion batteries currently have an average discharge capacity of around 360 ah/kg, or about the first discharge capacity of the lowest performing coin cell in the test.

The three best-performing cells used milled and spheroidized graphite; cell 1209 used un-milled but spheroidized graphite; and 1211 used naturally occurring spheroid graphite.

Tru Group Inc., a technology metals consultant with expertise along the graphite-graphene supply chain, had previously identified Graphite Creek as containing naturally occurring spheroidal, thin, aggregate and expanded types of graphite.

These unique and naturally occurring properties have prompted Graphite One to apply for the trademark, STAX, to describe the graphite sourced at Graphite Creek.

TRU Group Vice President John Roumeliotis said, "The STAX graphite is performing robustly and in the manner in which we had predicted during TRU's initial investigation of the Graphite Creek deposit.

It was anticipated that the morphology observed in the drill core samples would translate into processing and performance gains over conventional flake graphite. In addition to first discharge capacity, the coin cell tests also demonstrated the ability of the STAX graphite to achieve the same or similar discharge capacity in repeated subsequent charging-discharging cycles.

This behavior was evident in both the highest-performing and lowest-performing cells.

"These results support our material having demonstrated superior first discharge capacity for uncoated graphite, while the continuous cycling test shows the potential for our SPG (spheroidized graphite) to be used in EV (electric vehicle) applications," said Graphite One CEO Anthony Huston.

At present, electric vehicle battery manufacturers use more expensive synthetic graphite to offset the lower-performance of natural flake graphite.

"Up to this point, EV battery end-users have had to make a choice between systems that deliver high-power (near 100 kW) and high-energy (tens of kW hours between each charge). Based on these new results and observations made when processing STAX graphite, we will focus our development work on determining whether our STAX-derived SPG can deliver both high-energy and high-power performance," Huston said. "By displacing the need for synthetic graphite, higher-performance natural graphite produced at lower cost could deliver EV battery cost savings, one of the key factors in making EVs more affordable."

The coin cell test results using uncoated spheroidized graphite provide will be compared against coated spheroidized graphite coin cell tests now underway.

The graphite used for both tests was extracted from surface historic mine working samples which were first segregated into three lots by visual inspection. Each lot was then analyzed to determine which of the three corresponded to the mineralogy of the higher graphite grading zone (Zone 1) targeted for initial exploitation as identified in a conceptual study prepared by TRU Group.

"The graphite concentrate extracted from the surface sample used in this exploratory (research and development) phase conforms to graphite that was similarly extracted and characterized from samples originating from drill core segments that were from Zone 1," said Roumeliotis.

Follow-up testing will be conducted on graphite concentrate produced from work currently underway that is validating the mineral processing flowsheet using drill core segments from Zone 1.

Graphite One's Graphite Creek deposit has 17.95 million metric tons of indicated resource grading 6.3 percent graphitic carbon and 154.36 million metric tons of inferred resource at 5.7 percent graphitic carbon.

The Graphite Creek project is progressing from exploration to evaluation phases.

"It is important to note that the economics of the project have not been established at any level of confidence through the completion of a preliminary economic assessment, preliminary feasibility study or feasibility study," cautioned Huston.

-SHANE LASLEY