SOLiTHOR’s solid-state electrolyte hits 465 Wh/kg at stack level, passes nail penetration test

Belgian battery startup SOLiTHOR has announced a significant breakthrough with its solid-state electrolyte technology, achieving an energy density of 465 Wh/kg and 1,400 Wh/L at the stack level in a multilayer pouch cell design. This milestone was reached by impregnating their sol-gel Solid Composite Electrolyte into a high-loading cathode, eliminating the need for any liquid electrolyte—a key differentiator from other semi-solid and hybrid battery approaches. The technology demonstrated impressive performance, including continuous discharge rates of up to 5C with minimal capacity loss and pulse discharges at 10C, highlighting its potential for high-power applications. The company’s multilayer pouch cells, tested at room temperature, have shown robust cycle life, maintaining over 80% of their initial capacity after more than 500 discharge cycles. SOLiTHOR has also scaled up production with a 10 Ah demonstration cell that successfully passed rigorous safety tests, including overcharge and nail penetration, without any signs of thermal runaway, smoke, or leakage. This safety profile is particularly notable given the challenges solid-state batteries often face in terms of stability and reliability under stress conditions. SOLiTHOR’s manufacturing process is designed for efficiency and compatibility with existing lithium-ion production lines, eliminating the electrolyte-filling step and reducing formation and ageing times by two-thirds. These improvements could significantly cut production costs, as formation and ageing currently represent up to a quarter of lithium-ion battery manufacturing expenses. The company’s roll-to-roll compatible process offers a practical pathway for industry adoption without the need for costly new equipment. The startup is targeting high-value sectors such as aerospace, defence, and mobility, with its solid-state technology already receiving initial funding from the European Defence Fund through the DEEP-TECH project, aimed at deep-sea autonomy applications. Dr Fanny Bardé, co-founder and CTO of SOLiTHOR, emphasised that these technical achievements not only validate the chemistry but also demonstrate the balance of energy density, power, and cycle life necessary for real-world use. The company also highlighted its accelerated development cycle, enabling faster iterations and more impactful performance improvements.