Unveiling Essentials and Prospects of Electrolytes for Li/CF_x Primary Battery: A Review

The lithium/fluorinated carbon (Li/CF_x) primary battery is renowned for its high theoretical energy density and is eagerly anticipated for applications in environments lacking external power sources. However, its application is currently confined to small-scale uses due to challenges like maintaining low energy density at subzero temperatures, slow reaction kinetics, and a relatively low discharge voltage. The electrolyte, a crucial component, addresses these issues by not only regulating Li⁺ transport, similar to other lithium-ion batteries but also by facilitating the breakdown of C─F covalent bonds and the decomposition of LiF during discharge. Hence, a thorough understanding of the electrolyte is vital for enhancing battery performance in terms of both intrinsic characteristics and interactions with discharge intermediates. In this review, electrolyte-driven electrochemical mechanisms are comprehensively elaborated and then examine advanced electrolyte optimizations that have achieved exceptional rate capability and energy density across all climate conditions. Additionally, current challenges and potential research directions are discussed for electrolytes, aiming to broaden the horizons for Li/CF_x batteries.