In a report published in ACS Applied Energy Materials, researchers have presented a novel lithium-ion battery anode design that achieves some of the highest energy storage capacities reported for silicon carbon nanotube systems, while maintaining stability over hundreds of charge cycles.
Lithium-ion batteries currently power a wide range of technologies, including smartphones, wearables, and electric vehicles. While graphite remains the most widely used anode material due to its stability, it is limited in storage capacity. Silicon offers significantly higher capacity but suffers from expansion during charging, leading to structural degradation over time.
VISiCNT Design Addresses Silicon Challenges
To overcome these limitations, the research team developed a “Vertically Integrated Silicon–Carbon Nanotube” (VISiCNT) structure. This design involves growing dense carbon nanotube forests directly onto copper foil and coating them with a thin silicon layer. The resulting structure forms a flexible and conductive scaffold capable of accommodating silicon expansion without compromising performance.
Laboratory tests showed that the anode delivers storage capacities exceeding 3500 milliampere-hours per gram, approaching silicon’s theoretical maximum and far surpassing the 370 mAh/g typical of graphite-based anodes. The design also demonstrated improved stability across repeated charge cycles.
Expert Insights on Breakthrough
Dr Muhammad Ahmad, Research Fellow, stated, “There’s been a growing push for battery innovation, as many of today’s technologies are limited by how much energy batteries can store. Our VISICNT design offers a practical route to harness silicon’s huge storage capability without sacrificing cycle life.
“This is a much-needed breakthrough, delivering very high capacity, fast charging and long-term durability, while bringing us closer to batteries that can power electric vehicles and everyday devices for much longer on a single charge “
Scalable Manufacturing and Industry Potential
A key advantage of the VISiCNT approach is that carbon nanotubes are grown directly onto copper, a material already used in commercial batteries, using a scalable manufacturing process. This increases the feasibility of integrating the technology into existing production lines.
Professor Ravi Silva, Distinguished Professor, Interim Director – Institute for Sustainability (IfS), Director – Advanced Technology Institute (ATI) and Head of NanoElectronics Centre, said,
“This work is an important step towards bringing CNT-silicon anodes out of the lab and into real-world manufacturing. We can grow carbon nanotube structures directly onto copper foil at speed and tailor the silicon layer for stability, meaning this approach could be integrated into existing battery production lines with minimal disruption. The technology has clear potential not just for electric vehicles, but also for grid storage and smaller batteries used in microelectronics.
“We are very proud to present yet another CNT technology following our initial research in delivering the world’s darkest material, VANTA-Black via the university spin-out Surrey NanoSystems Ltd., which is showing real-world impact of fundamental research funded by UKRI. “
Supporting the Transition to Net Zero
As global demand for energy storage rises, innovations like VISiCNT could play a crucial role in enabling higher energy density, faster charging, and longer-lasting batteries key requirements for supporting the transition to Net Zero and powering next-generation devices and electric mobility solutions.
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