Altech’s silicon breakthrough supercharges lithium-ion battery performance

• Altech’s silicon anodes retain 88.5% capacity after 500 charge cycles, proving breakthrough stability
• Technology delivers 40% capacity boost over standard graphite anodes, enabling longer EV range
• Alumina-coated silicon spheres prevent damaging expansion by fitting into graphite anode gaps

Special Report: Altech Batteries’ Silumina Anodes™ have reached a major breakthrough, demonstrating 88.5% capacity retention after 500 charge-discharge cycles with a repeat test proving reproducibility and process stability.

The results were returned from a 5% addition of the company’s proprietary alumina-coated spherical silicon anode material to a graphite anode.

Silicon has long been recognised to be capable of greatly increasing the energy density of lithium-ion batteries as it can theoretically store up to 10 times as many lithium ions as graphite.

However, its potential has long been limited because the adsorption of silicon ions is accompanied by swelling of up to 300%, leading to mechanical stress, particle fracture, and rapid capacity loss.

For Altech Batteries (ASX:ATC), successfully incorporating silicon into battery anodes to boost energy density while maintaining exceptional long-term stability marks a major technical breakthrough.

“These latest results mark a genuine breakthrough for the battery industry. Achieving 88.5% retention at 500 cycles with a 5% silicon addition confirms the stability of our Silumina Anodes™  process,” managing director Iggy Tan said.

“Our team in Saxony continues to deliver highly consistent results, validating the technology and scaling methods.

“Altech’s breakthrough positions us at the forefront of next-generation anode materials, unlocking longer-lasting, higher-capacity lithium-ion batteries.”

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How Silumina Anodes work

The company’s Silumina Anodes™  technology overcomes the silicon expansion issue by transforming irregular silicon particles into perfectly rounded, alumina-coated spheres that integrate seamlessly within graphite anodes.

When blended into the graphite anode matrix, the spherical Silumina particles naturally occupy microscopic voids, where they can expand and contract freely during cycling without damaging the surrounding structure.

In the company’s test, battery cells containing 5% silicon in the anodes recorded an initial capacity of 500 mAh/g, a >40% improvement over the specific capacity of 350 mAh/g for graphite only anodes.

The increased capacity of anodes with Silumina particles was also largely retained over the long-term, dropping down to about 420 mAh/g after 500 charge-discharge cycles vs the decline to 230-250 mAh/g for graphite only anodes.

A 40-50% increase in anode capacity typically equates to a 20-25% gain in total cell energy, depending on cathode pairing.

With higher capacity available in the anode, designers of the next generation lithium-ion battery cells can either increase total energy density or reduce battery mass and volume while maintaining range.

For electric vehicles, increased energy density translates directly into longer driving range per charge, or smaller and lighter battery packs, and improved overall vehicle efficiency.

Higher anode capacity also improves volumetric energy density – a critical parameter for portable electronics, drones, and aerospace systems where every cubic centimetre matters.

More broadly, it demonstrates a practical pathway to incorporate silicon without compromising durability or safety.

Pilot plant progress in Saxony

The company has established a fully equipped pilot plant adjacent to the proposed commercial site at Dock 3 in Saxony, Germany, to support product qualification and process optimisation.

This is aimed at accelerating development of its Silumina Anodes™ technology.

The facility is now operating smoothly, producing multiple batches of high-quality alumina-coated silicon particles that demonstrate excellent consistency with results from Altech’s Perth laboratory.

Several silicon sources are being trialled to assess performance, purity, and cost efficiency, ensuring robust supply-chain flexibility.

This article was developed in collaboration with Altech Batteries, a Stockhead advertiser at the time of publishing.

This article does not constitute financial product advice. You should consider obtaining independent advice before making any financial decisions.