Surface treatment of Artificial Graphite for Anodes in Lithium-Ion Batteries

Graphite is today the dominating anode material for lithium-ion batteries (LIB) and represents around 15% of the batteries weight. During charging, the Li-ion will insert in between the layers in the graphite. The lithium diffusion rate around the particles and inside the graphite particles is generally slow. The more you charge the battery, the more Li-ions will be inserted into the graphite. This will in turn make it harder for new Li-ion insertion and therefore strongly limit how fast the battery can be charged without causing damage. In this project, SAGA, we utilized surface treatment on graphite materials to improve the fast charge (and discharge) properties. Both fossil-based conventional and an alternative environmentally friendly methods were used. The modified materials obtained from all the methods exhibit similar properties and similar performance as the benchmark samples. In the initial phase of the project, a different process has been employed to modify the graphite surface in the lab scale reactors. With the support of SINTEF, a fast and easy physical characterization method to monitor the surface modification and to check the uniformity of the samples was developed in 2021. In the first and second quarter of 2022, the process condition in the pilot scale is optimized to produce the materials with the same quality as the one produced in the lab scale. Some of the products developed during the project also tested at customers' side and got positive feedback. The project results will be directly utilized in the ongoing pre-industrial project at Porsgrunn where the aim is to validate the production process of artificial graphite with lithium-ion batteries manufacturers in their pilot plant. New anode graphite products tailored for fast charge applications are expected to be produced as a result of the surface modification processes developed within SAGA. This will furthermore enable Vianode as one of the production facilities outside Asia with capability of delivering anode graphite to lithium-ion batteries for the growing demand in Europe, in particular for batteries to electric vehicles. An improved fast charge performance will also make sure that lithium-ion batteries will see a broader and faster implementation thus moving the society towards a fossil free and electric future.

The project results will be directly utilized in the ongoing pre-industrial project in Vianode at Porsgrunn where the aim is to validate the production process of artificial graphite with lithium-ion batteries manufacturers in their pilot plant. New anode graphite products tailored for fast charge applications are expected to be produced as a result of the surface modification processes developed within SAGA. This will furthermore establish one of the only production facilities outside Asia with capability of delivering anode graphite to lithium-ion batteries for the growing demand in Europe, in particular for batteries to electric vehicles. An improved fast charge performance will also make sure that lithium-ion batteries will see a broader and faster implementation thus moving the society towards a fossil free and electric future. Replacing fossil feedstocks for graphite production with bio-carbon (for surface modification) and recycled graphite will be important for future growth of the industry as part of a circular economy.

Elkem is planning industrial scale production of artificial graphite for anodes in lithium-ion batteries in the coming years, to be able to supply the growing demand in Europe for lithium-ion batteries. Particularly the battery demand for electric vehicles will be high, which requires high performance material capable of fast charge without compromising lifetime, energy density and safety. EU has a strong focus on sustainability throughout the value chain, and securing raw materials in Europe with low carbon footprint is highly valued. The idea of this project is therefor to improve the fast charging capability and reduce the carbon footprint of artificial graphite. This will be accomplished by increasing the first generation product life of graphite and developing second generation products of recycled and bio based graphite materials. Charging of lithium-ion batteries, and in particular fast and low temperature charging of graphite is the most important ageing mechanism in lithium- ion batteries so will be the focus for extending the first generation product life. The technical approach will focus on advanced surface treatments and mixed potential composite surface designs to encourage fast ion transport through the solid electrolyte interface. Reuse of graphite from end of life lithium-ion cells with new surface treatment methods and replacement of virgin fossil based coating materials with bio materials will be the technical approach for second generation materials.