2 Mn-based Li-excess cation-disordered rocksalt (DRX) oxyfluorides are promising candidates for 3 next-generation rechargeable battery cathodes owing to their large energy densities, earth-4 abundance of Mn and potential for low cost. In this work, we synthesized and electrochemically 5 tested four representative compositions in the Li-Mn-OF DRX chemical space with various Li 6 and F content. 7 material with high Li-excess (1.3333 per formula unit, Li x Mn2x O2y F y) and moderate fluorination 8 9 Higher fluorination (0.6667 per formula unit) at moderate Li-excess (1.25 per formula unit) can Wh/kg) initial capacity (specific energy) with more than 85% retained after 30 cycles. We show that the Li-site distribution (i.e., Li percolation properties) plays a more important role than the metal-redox capacity in determining the initial capacity, whereas the metal-redox capacity is more closely related to the cyclability of the materials. We apply these insights and generate a capacity map of the Li-Mn-OF chemical space, Li x Mn2x O2y F y (1.167 ≤ x ≤ 1.333, 0 ≤ y ≤ 0.667), which predicts both the accessible Li capacity and Mn-redox capacity. This map allows to design compounds which balance high capacity with good cyclability. activate Mn 2+ /Mn 4+ redox and there by balance capacity with cycle life, achieving 256 mAh/g (822 (0.3333 per formula unit) achieves 349 mAh g-1 initial capacity and 1068 Wh kg-1 specific energy. While all compositions tested achieve higher than 200 mAh g-1 initial capacity, the
Here, we synthesized a series of α-MnO2 samples with differing K+ content but similar physical properties allowing direct study of the role of tunnel K+ on the electrochemistry of α-MnO2 cathodes.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.