Lithium-ion and solvent co-intercalation enhancing the energy density of fluorinated graphene cathode

Fluorinated carbons CFx hold the highest theoretical energy density (e.g., 2180 W h kg-1 when x = 1) among all cathode materials of lithium primary batteries. However, the low conductivity and severe polarization limit it to achieve its theory. In this study, we design a new electrolyte, namely 1 M LiBF4 DMSO:DOL (1:9 vol.), achieving a high energy density in Li/CFx primary cells. The DMSO with a small molecular size and high donor number successfully solvates Li+ into a defined Li+-solvation structure. Such solvated Li+ can intercalate into the large-spacing carbon layers and achieve an improved capacity. Consequently, when discharged to 1.0 V, the CF1.12 cathode demonstrates a specific capacity of 1944 mA h g-1with a specific energy density of 3793 W h kg-1. This strategy demonstrates that designing the electrolyte is powerful in improving the electrochemical performance of CFx cathode. (c) 2023 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by ELSEVIER B.V. and Science Press. All rights reserved.