Altech Chemicals Limited (ASX: ATC) has successfully applied its alumina nano layer coating technology to the coating of silicon particles, typical of those used in anode applications within lithium-ion batteries.
The application of Altech’s technology to coat silicon particles follows its December 2020 success in the alumina nano layer coating of graphite particles typical of those used in a lithium-ion battery.
General Manager operations and Chief Scientist, Dr Jingyuan Liu, said that extending the application of the technology to the coating of silicon particles is a significant breakthrough for Altech, especially in the context of a recent public statement of US electric vehicle manufacturer Tesla, that its aim is to increase the amount of silicon in its batteries to achieve step-change improvements in energy density and battery life.
Silicon has a significant advantage over graphite for use in lithium-ion battery anodes in that it has ten times the theoretical energy capacity compared to graphite.
However, limitations for silicon use in battery anodes have included particle volume expansion of up to 300% when energised, and a large “first cycle lithium loss”. Industry believes that the encapsulation of silicon particles via the application of a nano layer of alumina can resolve these issues and be a “game changer” which would pave the way for increased lithium-ion battery energy density, lifespan and reduced first cycle lithium loss.
To test its fine particle alumina coating technology, Altech used silicon samples that were provided by its collaboration partner Silico Ferrosolar, a subsidiary of the Ferroglobe Group.
The nano coating of alumina onto lithium-ion battery grade anode materials such as silicon, has been very difficult for industry to achieve. In the case of silicon particles they have unique characteristics that required Altech’s coating technology to be adjusted in order to achieve the required outcome.
Altech was able to deposit a uniform and consistent layer of alumina on the outer edge of the silicon particle, encapsulating the particle, this is Altech’s alumina coating technology.
Dr Liu said that verification of Altech’s coating technology on silicon particles is very exciting for the company.
We are very encouraged by the excellent coating results achieved from the application of our technology, it has the potential to significantly increase the use of silicon in lithium-ion battery anode and consequently the potential to increase battery energy density, overall performance and longevity. The next step is to further optimise the coating process”, he said.
