The ALISA project (Advanced Lithium–Sulfur batteries with ultramicroporous carbons) addressed one of the key challenges in developing next-generation rechargeable batteries: enabling high-energy, sustainable, and safe lithium–sulfur (Li–S) cells. Unlike conventional lithium-ion technology, Li–S batteries rely on abundant and low-cost sulfur, offering the potential for significantly higher energy densities and reduced environmental impact.
Sulfur cathodes and electrolytes were optimized through innovative infiltration methods and systematic benchmarking of carbonate-based electrolytes. Operando and ex situ characterization techniques such as SAXS/SANS, XRD, XPS, and cryo-TEM provided unprecedented insight into how sulfur converts inside nanopores and how the cathode–electrolyte interphase (CEI) forms and evolves during cycling.
ALISA successfully demonstrated that Li–S batteries with novel porous carbons and optimized carbonate electrolytes can achieve stable, long-life operation at the laboratory scale. The project generated new mechanistic understanding of sulfur conversion and CEI chemistry, delivered a wide portfolio of advanced carbon materials, and highlighted both opportunities and challenges for scaling towards practical devices. The outcomes provide a strong foundation for future European research and industrial innovation in post-lithium battery technologies.
Main findings («Take-Home Messages»)
- ALISA developed a broad portfolio of tailored porous carbons, including biomass-derived materials, with controlled ultramicroporosity and surface chemistry for improved sulfur confinement.
- Optimized sulfur infiltration and carbonate-based electrolytes enabled reversible solid-state sulfur conversion and stable laboratory-scale cycling, including more than 300 cycles with selected biocarbon cathodes.
- Advanced operando and ex situ characterization clarified sulfur conversion inside nanopores and the formation of the cathode–electrolyte interphase, while data-driven modelling accelerated SAXS/SANS analysis by approximately 1000 times.
- By advancing sustainable battery materials, training researchers, and identifying the remaining scale-up challenges, ALISA strengthened the European and Swiss knowledge base for future energy-storage technologies. The project supports Swiss energy-policy objectives by promoting innovation in resource-efficient batteries based on abundant sulfur and carbon materials.
The ALISA project (Advanced Lithium–Sulfur Batteries with Ultramicroporous Carbons) successfully explored, designed, and validated novel carbon hosts, electrolytes, and characterization approaches for next-generation Li–S batteries. Over its 36-month duration from September 2022 to August 2025, the consortium generated fundamental scientific knowledge, demonstrated new material architectures, and identified important challenges for industrialization.
A broad library of porous carbons was synthesized and optimized, including carbide-derived carbons, novolac-derived carbons, Porocarbs, carbon spherogels, and biomass-derived carbons such as olive-pomace-based CB700. Controlled pore sizes between 0.7 and 1.8 nm and heteroatom functionalization with nitrogen and phosphorus enabled the surface chemistry and sulfur confinement properties of these materials to be tailored systematically.
A robust sulfur-infiltration protocol was established, and systematic benchmarking identified carbonatbased electrolytes with high FEC content as the most stable systems for reversible solid-state sulfur conversion. High-sulfur-loading cathodes containing NPC and Porocarb materials achieved stable cycling for more than 50 cycles, while selected biocarbon cathodes retained capacities of approximately 850 mAh g?¹ for more than 300 cycles. A pouch-cell prototype was also fabricated, demonstrating the feasibility of transferring the developed concepts to a larger format while revealing remaining challenges related to lithium-metal stability and electrolyte distribution.
Operando SAXS/SANS, XRD, XPS, and cryo-TEM provided new mechanistic insights into sulfur conversion and cathode–electrolyte interphase formation. The results confirmed solid-state sulfur conversion within micropores and showed that CEI chemistry strongly depends on the electrolyte and applied voltage. Carbonate-based electrolytes formed comparatively robust, inorganic-rich interphases, whereas ether-based electrolytes resulted in less stable, polysulfide-dominated interphases. CNN-based SAXS/SANS modelling accelerated data analysis by approximately 1000 times, enabling substantially faster processing of complex operando datasets.
The project also achieved extensive scientific dissemination and researcher training. Its results contributed to more than ten high-impact publications, presentations at major international conferences, and an open-access Zenodo repository. Despite the withdrawal of one industrial partner during the project, the consortium successfully redistributed the affected tasks without compromising overall progress.
Overall, ALISA established important structure–property relationships for advanced porous carbons, clarified the mechanisms governing sulfur conversion and CEI formation, and identified promising materials and electrolytes for future development. At the same time, it defined critical bottlenecks for practical implementation, particularly pouch-cell scale-up and lithium-metal stability. By advancing battery technologies based on abundant sulfur and tailored carbon materials, the project contributes to the research and innovation needed for more sustainable energy storage and supports the broader objectives of Switzerland’s Energy Strategy 2050.
