ZSW – Innovative Silicon Anodes Increase Lithium-ion Batteries Energy Density and Sustainability
ACILE project combines fiber, nonwoven, and semiconductor technologies
A new research project involving four partners based in Baden-Württemberg – one being the Centre for Solar Energy and Hydrogen Research Baden-Württemberg (ZSW) – aims to advance the state of the art in battery technology. Called FACILE, this project seeks to increase lithium-ion batteries’ energy content by developing innovative silicon-based anode materials. To this end, the industry and science consortium intends to combine proven paper and nonwoven production processes with sophisticated industrial coating techniques used in semiconductor and photovoltaic engineering. The goal is to boost the practical energy density on the anode side by up to 250 percent as well as to improve batteries’ environmental footprint. The Baden-Württemberg Ministry of Economic Affairs, Labor, and Tourism is funding the project with €1.28 million. Launched on July 1, 2025, it will run for 24 months, concluding on June 30, 2027.
Prof. Dr. Markus Hölzle, member of the board and head of the ZSW in Ulm, says:
FACILE shows how industry and science in Baden-Württemberg can jointly cover the entire value chain for lithium-ion batteries, from material development to cell production,
“The project goes to develop silicon anodes on flexible nonwoven fabric substrates that compensate for significant volume changes in the material. This will result in powerful, durable, and sustainable batteries – and make important contribution to strengthening the region’s competitive stance.”
Conventional anodes – that is, lithium-ion cells’ negative poles – are made of graphite, which can store lithium at up to 370 milliampere hours per gram. Silicon, in contrast, can theoretically store up to 4,200 milliampere hours per gram – more than ten times as much as graphite. While silicon and graphite costs’ are comparable, silicon is abundantly available worldwide and thus more sustainable.
Fibers, not fractures: Reinventing silicon anodes
The Baden-Württemberg-based partners in this project are determined to use silicon to increase the anode’s actual energy density by at least 250 percent, thereby achieving no less than 1,000 milliampere hours per gram of practical capacity. The great challenge is that silicon’s volume changes markedly during charging and discharging. Unless suitable countermeasures are taken, this soon causes cracks and peeling on the anode, which can result in battery failure. This is where FACILE enters the picture. It is the first attempt to develop silicon anodes on fiber-based, electrically conductive nonwoven substrates. Their flexible, fiber-based structure is designed to accommodate the volume changes in silicon. The resulting composite material pairs high performance and long service life with sustainability in an innovation that is truly ‘made in Baden-Württemberg.’
Building and validating test cells
The ZSW at Ulm started off by trialing in small test cells the fiber-based silicon anodes produced in the project. Next the scientists will analyze, refine, and scale up the production processes for manufacturing large battery cells such as those that power electric vehicles. The institute brings a great deal of expertise to this task: It operates several cell manufacturing pilot plants. One is a factory-like research production line for making large lithium-ion cells with up to 100 ampere hours capacity. It has been up and running since 2014.
ZSW scientists have amassed decades of experience assessing the safety and performance of batteries and prototypes. Set up in 1998, the institute’s battery safety and testing center is renowned across Europe.
Baden-Württemberg project spans the entire value chain
The project covers all the key steps involved in manufacturing innovative lithium-ion batteries – new anode materials development, manufacturing processes, plant engineering, material testing, methods development, and battery cell production. The partner organizations draw on their particular technology expertise to help select, develop, and optimize suitable processes.
The project is called Development & Production of Innovative, Fiber- and Silicon-Based Anode Materials for High-Performance and Sustainably Produced Li-Ion Batteries, or FACILE for short. It is coordinated by centrotherm international AG based Blaubeuren. This mechanical engineering company’s task within the research project is to develop an innovative high-throughput system for applying silicon coatings to fiber materials. There are several more partners on board: Phoenix NonWoven GmbH & Co. KG in Lenningen is developing and will deliver the specialized nonwoven fabrics. The International Solar Energy Research Center Konstanz (ISC Konstanz e.V.) is investigating the bond between the nonwoven fabric and the copper foil, while the Photovoltaics department at the University of Konstanz is conducting material analyses. Finally, the Centre for Solar Energy and Hydrogen Research Baden-Württemberg (ZSW) in Ulm is tasked to characterize, make, and test the advanced fiber-based anode in full-fledged battery cells.
READ the latest Batteries News shaping the battery market
ZSW – Innovative Silicon Anodes Increase Lithium-ion Batteries Energy Density and Sustainability, source
