This biography of materials intertwines the two social roles taken by lithium in medicine and industry. The first part compares the two historical narratives of lithium, as psychotropic and energy materials, that carry modern myths. In the second part, the two lithium-based materials are portrayed at an epistemic level through their ability for crossing the boundaries between nature and culture, between biological, organic, and mineral domains. The third part analyses the global supply chain of lithium for commercial products. This leads to characterize, finally, the two criticality of lithium in sociopolitical terms for energy storage; in ethical terms for psychotropic treatments.