Volt Resources Limited: High Performance Results From Bunyu Battery Cell Testwork

Highlights

-          Coin cell cycle testing demonstrates LIB grade material

-          Extremely low capacity loss after 100 charge/discharge cycles – testing is now past 170 cycles with continuing low capacity loss

-          Proprietary process flow sheet enables significantly higher yields of purified spheroidal graphite

-          Non-spherical fraction retains high level of purity and is currently undergoing performance testing in traditional battery systems with direct oversight by Volt’s potential offtake partner, which operates in the lead-acid battery market

-          Results facilitate current discussions with battery manufacturers and technology groups as the Company progresses with battery-ready coated spherical anode-grade graphite production plans in the USA and Europe

-          Feasibility studies to commence for battery anode production facilities in Europe and USA

-          Testwork program undertaken by U.S. company AETC as part of a technology integration program including long-term cycle testing of Bunyu graphite for lithium ion batteries (LIB)

Graphite producer and battery anode material developer Volt Resources Limited (ASX: VRC) (“Volt” or “the Company”) is pleased to report the successful LIB cell cycle testing results using coated spheronised purified graphite (“CSPG”) produced from natural graphite originated at Bunyu Resource in Tanzania. The results are reported below and show very low irreversible capacity loss after 100 cycles and the continuation of low capacity loss after 170 cycles. Low capacity losses relate to battery life and this measure is a key performance indicator for battery anode material to be used in the production of lithium-ion battery technologies. The testwork program was undertaken by an established commercial graphite producer and processor, American Energy Technologies Co. (“AETC”) which is headquartered in Illinois, USA.  

Volt’s Managing Director, Trevor Matthews, commented “We continue to be delighted with the battery cycle testwork results reported by AETC. This has confirmed Bunyu’s flake graphite is suitable for use in the production of battery-ready anode material for energy storage solutions.

“Now that we have completed 170 cycles of the battery cell testwork program with Bunyu flake, we will shortly commence feasibility studies for the development of battery anode production facilities in Europe and the USA. Additionally, we will undertake an evaluation and sampling program with a number of technology and battery end-user groups which we have engaged with in the past months, to further our commercialization objectives in the electric vehicle, consumer and energy storage battery platforms in Europe, the United States and Asia.

Volt will be adopting the inverted flow sheet for its downstream operations following the successful spheronisation and purification results achieved during the testwork program. The use of this flowsheet will allow us to not only convert a significant portion of our graphite into battery-ready anode material for lithium-ion batteries, but will also generate a range of ultra-high purity by-products for use as electrically conductive diluents in battery cathodes and in a variety of valuable non-battery applications.”

Battery Cell Cycling Testwork

The testwork program’s goal is to develop a technical support data package for market introduction of the Bunyu natural graphite product and the provision of battery-ready CSPG material for samples to be provided to potential LIB manufacturing customers.

The program involved the production of SPG, followed by its surface coating prior to commencing extended cycling in batteries. Cycling tests assess the initial electrochemical performance of carbon coated spherodised graphite in the industry standard CR2016 coin cells (i.e. reversible, irreversible capacity and irreversible capacity loss). The program is designed to perform long-term cycling (100 cycles initially), which is used to assess the viability of the Bunyu CSPG for energy storage applications.

CR2016 coin cells

Initial electrochemical performance of Bunyu Graphite is presented in the chart 1 below. This graph represents a galvanostatic charge-discharge curve commonly used in the industry to derive values of reversible and irreversible capacity, as well as first cycle efficiency. It is evident that Bunyu graphite has a reversible capacity on the order of 355 mAh[i]/g, with irreversible capacity loss amounting to less than ten percent (i.e. 8.04%).

Chart 1: Cycle characteristics.

Long-term Cycling Results

Chart 2 below illustrates the current status of 170 cycles of long-term cycling results. Three cells containing Bunyu CSPG are being used for the long-term cycling testwork. The results from the three cells cycling performance are shown below and are consistent with LIB battery-grade material’s specifications. It is worth noting that cells designed for long term cycling are intentionally built for slightly lower capacity ratings, therefore the reversible capacity values for the three cells in the test series range between 315 and 320 mAh/g. These cells demonstrate highly consistent performance with virtually negligible degradation from cycle to cycle. The flat curve signals that Bunyu graphite could compete not only with other natural graphite battery anode material (“BAM”), but also a great number of costlier synthetic graphite BAM offerings, in its long-term cycling performance.

The Cell Comparison Maximums reported in Chart 2 below show excellent cell-to-cell stability and extremely low 1.79% reversible capacity decay (or 98.21% capacity retention) after 100 cycles.  Further results were a low 2.69% reversible capacity decay (or 97.31% capacity retention) after 150 cycles and 2.83% reversible capacity decay (or 97.17% capacity retention) after 170 cycles.

Chart 2: Long Term Cycling Results

Battery Anode Material Flowsheet

In a traditional flowsheet, graphite concentrates are milled, and then shaped into a sphere. The particles that have been spherodised are purified by an environmentally damaging acid leaching process.  In addition, only 35%-40% of the graphite is spherodised and converted into battery-grade material. The non-spherical particles, amounting to 65%-70% of the feed in the traditional circuit, are collected and sold into lower-margin markets such as re-carburizers, pencils, aftermarket brake pads, and others.

With the flowsheet developed by AETC to produce spherical purified graphite (SPG), purification is completed first with all of the subsequent sizing and shaping undertaken with purified material. The purification process was undertaken exclusively using high temperature furnaces. No acid leaching or caustic bakes were employed.

The main benefits Volt enjoys from this inverted flowsheet are:

-          Reduced wear and tear on shaping mill parts (due to processing being accomplished with high purity graphite, which is a natural lubricant), and,

-          The ability to divert non-spherical portions of the purified graphite to higher-margin markets such as conductivity enhancement applications in LIB and other advanced battery cathodes.

With two world-class graphite resources incorporated in a strategically located operating mine and processing plant in Ukraine along with a development-ready project in Tanzania, Volt Resources is well-positioned to become a globally significant graphite producer.

Volt plans to become a battery anode material producer in Europe and the United States based on an integrated supply chain using graphite manufactured from its own operations. This provides security and continuity of supply for the business, and the ability to manage product quality through the global graphite supply chain through to the LIB cell manufacturers and for other value-add graphite product end users.

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This announcement was authorised for release by the Board of Volt Resources Ltd.

For further information please contact:

Trevor Matthews Managing Director Tel: +61 8 9486 7788

Alex Cowie

Investor Relations

NWR Communications

Tel: + 61 412 952 610

Follow us on Twitter @ASXVolt

About Volt Resources Limited

Volt Resources Limited (“Volt”) is a graphite producer/developer and gold exploration company listed on the Australian Stock Exchange under the ASX code VRC. Volt has a 70% controlling interest in the Zavalievsky Graphite business in Ukraine. Zavalievsky is in close proximity to key markets with significant developments in LIB facilities planned to service the European based car makers and renewable energy sector. Zavalievsky benefits from an existing customer base and graphite product supply chains based on excellent transport infrastructure covering road, rail, river and sea freight combined with reliable grid power, ample potable ground water supply and good communications. Zavalievsky has current plans to install a processing plant and equipment in order to commence production of spheronised purified graphite (SPG) for the European LIB market within the next 12 months[ii]. 

Volt is also progressing the development of its large wholly-owned Bunyu Graphite Project in Tanzania, as well as gold exploration in Guinea leveraging the Company’s existing extensive networks in Africa.

The Bunyu Graphite Project is ideally located near to critical infrastructure with sealed roads running through the project area and ready access to the deep-water port of Mtwara 140km from the Project. In 2018, Volt reported the completion of the Feasibility Study (“FS”) into the Stage 1 development of the Bunyu Graphite Project. The Stage 1 development is based on a mining and processing plant annual throughput rate of 400,000 tonnes of ore to produce on average 23,700tpa of graphite products[iii]. A key objective of the Stage 1 development is to establish infrastructure and market position in support of the development of the significantly larger Stage 2 expansion project at Bunyu.

The Guinea Gold Projects comprise 6 permits in Guinea, West Africa having a total area of 348km. The Projects are located in the prolific Siguiri Basin which forms part of the richly mineralised West African Birimian Gold Belt.

[i] Unit measure of electric energy over time

[ii] Refer to Volt’s ASX announcements titled “Volt to Acquire European Graphite Business following Completion of Due Diligence” dated 14 May 2021 and “Completion of the ZG Group Transaction Following Execution of New Convertible Securities Facility” dated 26 July 2021.

[iii] Refer to Volt’s ASX announcement titled “Positive Stage 1 Feasibility Study Bunyu Graphite Project” dated 31 July 2018. The Company confirms that it is not aware of any new information or data that materially affects the information included in this document and that all material assumptions and technical parameters underpinning the estimates continue to apply and have not materially changed.