Lithium Energy Limited (ASX:LEL) has confirmed plans to pursue commercial opportunities for using graphene produced from its 100% owned Burke Graphite Deposit, in lithium-ion batteries.
The Burke Graphite Deposit is located in northwest Queensland (125 km north of Cloncurry) and is one of the highest-grade graphite deposits in the world held by an Australian listed company.
The exceptionally high-grade nature of the Burke Deposit and its chemical composition also lends itself to efficient Graphene production technology, which is not available for a majority of lower grade graphite deposits.
Previous drilling has defined an Inferred Mineral Resource for the Burke Deposit as follows:
- 6.3 million tonnes @ 16.0% TGC (with a TGC cut-off grade of 5%) for 1,000,000 tonnes of contained graphite;
- Within the mineralisation envelope there is included higher grade material of 2.3 million tonnes @ 20.6% TGC (with a TGC cut-off grade of 18%) for 464,000 tonnes of contained graphite which will be investigated further
The Burke Deposit is located in within reach of well-developed transport infrastructure and logistics nearby and is potentially amenable to low cost open-pit mining.
Graphene usage in lithium-ion batteries is an emerging technology, where Graphene is used as an additive in the compound mix of the Cathode electrode terminal to effectively make the terminal more conductive. Graphene enhanced batteries allow for increased electrical density, more rapid recharge times, less weight, as well as having the ability to hold the charge longer which improves the battery’s lifespan.
Graphene is technically defined as a single atom layer of crystalline carbon in a two dimensional ‘honeycomb’ type structure, but the term “Graphene” is often extended to include material made up of multiple stacked single layers of (single layer) Graphene. Material comprising up to 10 layers of Graphene is sometimes referred to as “Few Layer Graphene” (FLG), whereas material with between 10–150 layers of Graphene is known as “Graphene Nano Platelet” (GNP).
The Burke Deposit contains graphite from which Graphene Nano Platelets (GNP) have been successfully extracted via Electrochemical Exfoliation (ECE).
The ECE process is relatively low cost and environmentally friendly compared to other processes, yet it can produce very high purity Graphene products. The ECE process is however not applicable to the vast majority of worldwide graphite deposits as it requires a TGC of over 20% and accordingly the Burke deposit has potentially significant Graphene processing advantages over other graphite deposits.
In 2017, a test was successfully undertaken on a sample of Burke graphite diamond drill hole core through a process known as “Electrochemical Exfoliation” (ECE) by Independent Metallurgical Operations Pty Ltd (IMO), to produce pure GNP material from raw Burke graphite.
In ECE, a lump of graphite is inserted as an anode in a chemical solution and then an electric current is passed through the solution, using the graphite as an anode. Layers of Graphene then “peel off” and can be collected through a relatively simple process.
The ECE process is relatively low cost and environmentally friendly compared to other processes – yet it can produce very high purity Graphene. It is particularly suited to naturally occurring high-grade graphite such as Burke graphite, where the exceptionally high-grade raw material (~20% TGC) and natural conductivity allow it to be used directly as an anode in the ECE process without the need for any grinding, flotation or other processing steps.
In order to capitalise on the commercial opportunities for using Graphene produced from the Burke Deposit in lithium-ion batteries, Lithium Energy is planning to undertake further test-work to optimise the production ECE process for producing high quality GNP, FLG and/or single layers of Graphene in commercial quantities.