New lithium-ion battery design could power longer-lasting electric vehicles and portable devices

In a study published in ACS Applied Energy Materials, researchers introduce a novel lithium-ion battery anode that delivers some of the highest energy storage capacities reported for silicon–carbon nanotube systems, while maintaining stability over hundreds of charge cycles. 

Lithium-ion batteries power much of modern technology – from smartphones and wearables to electric vehicles. Graphite, the most commonly used anode material, is stable but limited in the amount of energy it can store. Silicon, on the other hand, offers far greater capacity, but it expands during charging, causing it to crack and degrade over time. 

To overcome this, the research team developed a new “Vertically Integrated Silicon–Carbon Nanotube” (VISiCNT) structure. The design grows dense forests of carbon nanotubes directly onto copper foil and coats them with a thin layer of silicon, creating a flexible, conductive scaffold that can absorb expansion while maintaining performance. 

The resulting anode can store a very large amount of energy for its weight. In laboratory tests, it stored more than 3500 milliampere-hours per gram – close to the maximum possible for silicon and far higher than the graphite (370 mAh/g) used in today’s batteries. It also demonstrated improved stability and performance over repeated charge cycles.

A key advantage of the new approach is that the carbon nanotubes are grown directly onto copper – the material already used in commercial batteries – using a scalable manufacturing process. This could make it easier to integrate the technology into existing industrial production lines.

As demand for energy storage grows, batteries will need to store more energy, charge faster and last longer to support the UK’s transition to Net Zero. The VISiCNT design offers a promising route to meeting these challenges and could be key to powering next-generation electric vehicles and phones. 

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Notes to editors 

•  Dr Muhammad Ahmad and Professor Ravi Silva are available for interview; please contact mediarelations@surrey.ac.uk to arrange. 
• The full paper can be found here: https://doi.org/10.1021/acsaem.5c03862