Rio Tinto's (NYSE:RIO) decision to invest US$2.5B in expanding the Rincon lithium project in Argentina is a strategic move that underscores the company's commitment to securing a significant position in the global lithium market. In this article, we explore the strategic rationale behind Rio Tinto's move, analyze current factors shaping the lithium market, provide our sector outlook, and share our top picks in the lithium space.