Altech Chemicals Ltd (ASX:ATC) has launched and registered the product name Silumina AnodesTM for its alumina coated composite silicon/graphite lithium-ion battery anode material.
Based on Altech’s test work, its Silumina Anodes product is expected to provide for the manufacture of battery anodes, that when incorporated into a lithium-ion battery, result in a battery that has higher energy retention capacity by volume and weight compared to a battery using the incumbent graphite only battery anode.
The key differentiation point of Silumina Anodes is that it will be a composite material of silicon and graphite particles that have been coated with alumina, using Altech’s proprietary alumina coating technology.
At its Perth research and development laboratory, Altech has been successful in applying its alumina coating technology to both silicon and graphite particles, typical of those used in the anode of lithium-ion batteries.
Altech’s laboratory test work has demonstrated that a lithium-ion battery using an anode comprised of composite graphite and silicon particles coated with alumina, improved battery energy capacity, energy retention, life and performance when compared to a conventional lithium-ion battery using a graphite only anode (the incumbent technology).
Background
On 25 November 2021, Altech announced a significant breakthrough achieved by its research and development laboratory located in Perth, Western Australia.
After almost 12 months of challenging work, the R&D team “cracked the silicon barrier” and successfully produced a series of lithium-ion battery anode materials, which when tested showed ~30% higher energy retention capacity compared to conventional graphite only lithium-ion battery anode material.
To achieve its breakthrough, Altech successfully combined silicon particles that had been treated with its innovative proprietary coating technology with regular battery-grade graphite particles, to produce a lithium-ion battery electrode containing a composite graphite/silicon anode.
When energised, these materials held 30% more capacity compared to a conventional graphite only anode material.
Also, the previously unresolved obstacles for using silicon in lithium-ion battery anodes were, silicon particle swelling; prohibitive first-cycle-capacity loss of up to 50%; and rapid battery degradation from each charge and discharge cycle.
Each of these were also resolved during the laboratory testing of Altech’s composite graphite/silicon battery anodes.
Importantly, the batteries demonstrated extremely good stability and cycling performance over extended periods.
Race to crack the silicon barrier
The lithium-ion battery industry has recognised that the required step-change to increase lithium-ion battery energy density and reduced cost is to introduce silicon into battery anodes, as silicon has ~ ten times the energy retention capacity compared to graphite.
Silicon metal has been identified as the most promising anode material for the next generation of lithium-ion batteries.
However, until now silicon was unable to be used in commercial lithium-ion batteries due to two critical drawbacks.
Firstly, silicon particles expand by up to 300% in volume during battery charge, causing particle swelling, fracturing and ultimately battery failure.
The second challenge is that silicon deactivates a high percentage of the lithium ions in a battery.
Lithium ions are rendered inactive by the silicon, immediately reducing battery performance and life.
The industry has been in a race to crack the silicon barrier.
Altech’s potentially game-changing technology has demonstrated that silicon particles can be modified to resolve the capacity loss caused by swelling and first-cycle-loss capacity.
Phase 2 of Altech’s planned R&D program will see the company strive to improve on the 30% energy increase achieved in the first phase.