Unlocking silicon’s promise: a novel process for making high-performance anode material

Silicon anodes have long promised to supercharge lithium‑ion batteries – offering a much higher energy storage capacity than today’s graphite alternatives. But this potential has remained largely out of reach because silicon swells dramatically during charging and is it costly to manufacture at scale. Now a University of Sheffield spin‑out, AmpliSi, has developed a new process for producing porous silicon anode material that overcomes these challenges – opening a path to higher‑performing, and more sustainable batteries.

Refined through two Faraday Institution projects, AmpliSi’s technology solves both product and manufacturing barriers that have held back use of silicon anodes. With a scalable, cost-effective method for manufacturing silicon in a more sustainable way, and £2 million of funding secured in March 2026, the company is now looking to scale up its operations.

Silicon, derived from abundant sand, offers a sustainable, high-capacity option if its limitations can be engineered out. It has a far greater theoretical capacity than graphite – enabling, for example, extended EV range. However, producing silicon anode materials has so far been a costly and time-consuming process, and the material itself swells significantly when charged. This causes significant physical stress, leading to cracking, loss of electrical contact, a decrease in capacity, and ultimately, battery failure. This has meant that while silicon-graphite blends are already in use in batteries for selected applications, the amount of silicon used in the blend remains low due to these issues.

Gwen says:

AmpliSi has solved a ‘product’ and a ‘process’ challenge for silicon anodes. The product challenge was developing a porous structure, which means that when the battery charges, the anode can absorb the expansion inwards, rather than just swelling outwards, which puts pressure on other particles in the microstructure.”

For the process challenge, the team looked for an alternative to silane deposition, the typical method used to synthesise silicon for use in industries such as semiconductor production. Gwen continues:

Silane gas is difficult to work with, and it’s an expensive and energy-intensive process. We needed something that could translate to a much larger scale to make the quantities of silicon needed in global battery manufacturing supply chains.”

While silane-based routes are technically scalable – and used commercially by some companies – cost and processing complexity remain considerations for battery-grade silicon production.

AmpliSi uses a magnesiothermic process, where silicon dioxide powder is heated with magnesium. Gwen explains:

The magnesium strips the oxygen off, and you’re left with magnesium oxide and pure silicon. Our patented process means we can do this at a relatively low temperature, less than 400°C, whereas traditional magnesiothermic silicon production would usually require a temperature of anywhere from 650-1000°C. We have unpicked the kinetics of the reaction and exploited unused reaction pathways.”

This offers the potential for less expensive, more sustainable anode material. Techno-economic analysis has demonstrated that the AmpliSi method can reduce cost of silicon production by 30% per kWh. The process is also intrinsically scalable.

Amplifying impact

AmpliSi’s processes were developed at the University of Sheffield in the lab of Professor Siddharth Patwardhan.

The team initially took part in a Faraday Institution Seed project to address the chemistry challenges around magnesiothermic reduction of silicon, then followed this up with a Faraday Industry Sprint with WMG at the University of Warwick that tested the process and looked at ways it could be scaled up.

Professor Patwardhan now serves as the company’s chief scientific advisor, and AmpliSi has recently recruited Dr Ruth Sayers, an experienced battery startup executive, as CEO.

As well as working with the Faraday Institution and the Commercialisation Journey at the University of Sheffield (a structured four-stage programme designed to support innovators to explore and maximise their commercialisation ambitions to investment readiness), the company was co-founded and spun-out of the University with deep-tech venture builder Cambridge Future Tech. The company’s founders have also completed NG Studios, Northern Gritstone’s venture building programme delivered by Deep Tech Labs.

In March 2026, AmpliSi secured a £2 million investment co-led by Northern Gritstone and Clean Growth Fund, that will enable AmpliSi to scale up its process for sampling by customers. 

Gwen says:

We can manufacture kilo-scale batches with current equipment, and we are looking to streamline that process. That would mean we can increase our cumulative material output as well as the single batch size.

We will use this investment to scale-up the silicon production process – to purchase the next, larger pieces of equipment, and grow the team to enable us to increase our throughput.”

As a first-time entrepreneur, Gwen says the support the founders have received from the Faraday Institution, as well their other partners, has been crucial. She says:

The way Faraday took us on as a Seed project enabled us to take those first steps in looking at the research and how we could ramp it up. The electrochemical testing carried out by the projects has been invaluable, too.”

The Sprint tested the performance of the new anode material in a range of configurations (including in three electrode cells) and formulations up to 100% silicon, generating performance data on capacity, stability and cell life.

Gwen concludes:

It has validated the commercial relevance and scalability of our technology and will stand us in good stead to move forward.”

 

Case study published in March 2026.