Altech Batteries Achieves 88.5% Capacity Retention in Silumina Anodes Breakthrough

Altech Batteries (ASX: ATC) has announced its strongest battery performance results to date, achieving 88.5% capacity retention after 500 charge–discharge cycles using a 5% addition of its proprietary Silumina Anode material.

The breakthrough marks a major advance in silicon-based anode technology, confirming both the stability and reproducibility of Altech’s process.

Managing director Iggy Tan said the results demonstrate that the company’s alumina-coated spherical silicon particles can deliver higher energy density without the rapid degradation that has limited silicon’s use in lithium-ion batteries.

Silicon Adds Energy, Alumina Adds Stability

Silicon can store nearly ten times more lithium than graphite, but it swells by up to 300% during charging, which causes mechanical stress and capacity loss.

Altech’s coating process eliminates this issue by encapsulating the silicon in a thin layer of high-purity alumina, allowing it to expand and contract without damaging the surrounding graphite matrix.

With just a 5% addition of Silumina Anodes to a graphite anode, Altech achieved an initial capacity of 500 milliamp hours per gram—more than 40% higher than conventional graphite—and maintained 420 mAh/g after 500 cycles.

These results represent a step-change in anode design, providing the durability of graphite with the performance benefits of silicon.

Transforming Design and Efficiency

Higher-capacity anodes allow manufacturers to either extend driving range or reduce pack weight while maintaining the same energy output.

Altech estimates that the improvement in anode capacity could increase total cell energy by 20–25%, depending on cathode pairing.

The company said this advance opens new possibilities for electric vehicles, drones, aerospace systems and grid-scale energy storage, where size, weight, and energy density are critical.

Mr Tan said the innovation solves one of the industry’s longest-standing challenges.

“Achieving 88.5% retention at 500 cycles confirms the stability of our Silumina Anodes process—putting Altech at the forefront of next-generation anode materials, and enabling longer-lasting, higher-capacity lithium-ion batteries.”

Pilot Plant Confirms Scalability

Altech is producing consistent batches of alumina-coated silicon material at its pilot facility in Germany, validating the reproducibility of its technology.

The plant sits adjacent to the proposed commercial production site at Dock 3 in Saxony and serves as a qualification hub for automotive and battery partners.

The company is also trialling multiple silicon feedstocks to optimise performance and cost, to ensure flexibility across different supply chains.

Mr Tan said these results confirm that Altech’s technology is ready to scale commercially and that discussions are already under way with potential offtake partners in Europe and North America.

Broader Battery Materials Portfolio

The 8,000-tonne-per-year Silumina Anodes project in Saxony is part of Altech’s broader battery materials portfolio, which also includes the CERENERGY sodium solid-state battery and AMPower sodium nickel chloride collaboration.

Together, these projects position the company as a battery innovator focused on sustainability, safety and performance.

Mr Tan said the work represents “a fundamental leap in energy storage capability, one that allows manufacturers to deliver longer-range vehicles, smaller and lighter packs, and more efficient energy systems.”