Alkali intercalated fullerides represent a competitive alternative to complex metal hydrides for static and on-board hydrogen storage applications, thanks to their good gravimetric absorption and their complete reversibility. Due to the many processes involved in the hydrogen chemisorption, a comprensive understanding of the hydrogen sorption mechanism remains an open challenge. Recent experiments and DFT studies suggested the important role of Li in the sorption process, involving the direct interaction with hydrogen, possibly forming covalent Li-H species. With this experiment we will study the temperature evolution of the different species formed by hydrogen with Li and C during the hydrogenation process, for different levels of hydrogenation.