Energy storage systems are main drivers in various fields, especially in the context of energy and mobility transition. Battery technologies are one of those options offering good technical performance in multiple stationary and mobile applications. New batteries having potentially high energy density and higher safety with lower cost are in particular ideal candidates for mobility applications. At present especially, lithium-ion batteries are used, but they are facing challenges regarding sustainability and safety issues, which can be quantitatively analyzed with Life Cycle Assessments (LCA). New developments regarding various solid-state batteries (SSBs) are very promising to tackle these challenges, but only very few studies are available on the environmental assessment of SSBs. Prospective LCA methodology is used here to analyze the environmental hotspots over the different life cycle phases for emerging SSBs. This also helps in decisions making at an early stage of development. This review critically analyzes available LCA studies on SSBs focusing on the inventory data, scope of the assessment as well as the life cycle impact assessment results. An effort has been made to compare the different LCA studies considering global warming potential indicator. As a results, the analysis highlights difficulties in comparability due to inconsistencies associated with the data sources, goal and scope, system boundaries and the method of impact assessment etc. To facilitate a consistent comparison, a unification methodology has been proposed to compare different LCAs of SSBs. Overall, the proposed methodology will help to fill the knowledge gap between different existing LCA studies on emerging solid-state battery technologies and provides recommendations for future assessments.