Sustainable batteries with ultra-high performances and smart functionalities will play a critical role in powering Europe’s transition from fossil fuels to renewable energies. Conventional lithium-ion batteries utilise a liquid electrolyte. Solid-state lithium-ion batteries, or lithium-metal solid-state batteries, use a solid electrolyte and lithium metal as the battery anode. These are garnering increasing attention for their promise of low cost, high performance and enhanced safety, yet they are far from achieving commercial viability. The EU-funded SOLiDIFY project is developing materials and manufacturing processes to bring their novel liquid-processed solid-state fabrication technology to fruition. Iwill enable successful integration of their solid nanocomposite electrolyte and fabrication of a new generation of lithium-metal solid-state batteries with Europe leading the charge.