A sinter-free future for solid-state battery designs

Ceramic-based solid electrolytes and separators are particularly attractive for use in next-generation batteries as a way to increase the electrochemical stability window and improve safety. However, batteries with higher energy densities require thin membranes comparable in thickness to the polymer separators (e.g., 10-25 μm) found in today's Lithium-ion batteries. To date, conventional ceramic-electrolyte processing routes have not been able to achieve this goal as they typically operate on the principle of sintering: going from particle to a densified ceramic body. To overcome this challenge, we provide a blueprint for an alternative cost-effective sequential decomposition synthesis (SDS) approach that uniquely accesses the thickness range required from solid Li oxide-based electrolytes close to those of today's polymer separators and offers immense opportunities for to obtain the desired phase at significantly lower processing temperatures (<700 °C) with unique ceramic microstructures. We specifically highlight the SDS processing of Li garnets and disclose basic SDS precursor and ceramic processing concepts that can be adapted to other Li-containing oxides.