Ultrafast Nano-Silver Modified Fluorinated Carbon Nanotubes Cathode Enables Advanced Lithium/Sodium/Potassium Primary Batteries

Abstract

The application of fluorinated carbon (CFx)-based lithium/sodium/potassium primary batteries (LPBs/SPBs/PPBs) with superior theoretical energy density in high-power devices remains limited due to the poor rate performance resulting from the low intrinsic conductivity of highly fluorinated CFx materials. Herein, novel nano-silver modified fluorinated carbon nanotubes (FCNTs@Ag-x) composites with high electrical conductivity were prepared without sacrificing the high fluorine content. The dual excellent performance achieved by the FCNTs@Ag-200 cathode is attributed to the three-dimensional conductive network synergistically constructed by the interlaced FCNTs and coated nano-Ag, together with electrochemically active C-F bonds co-regulated by Ag atoms and curvature, as well as abundant conductive semi-ionic C-F bonds and graphite-like sp2 C=C bonds, and few inactive C-F2 bonds. The FCNTs@Ag-200 cathode delivers very high energy densities of 2167, 1930, and 2150 Wh kg-1 for LPBs, SPBs, and PPBs, respectively, close to the theoretical energy density. The Li/FCNTs@Ag-200 battery exhibits an ultimate power density of up to 80501 W kg-1 at an ultrafast rate of 50 C and can withstand a pulse discharge of 150 C (~129.75 A g-1). Remarkably, unprecedented power densities of 36650 and 40672 W kg-1 are achieved at a record rate of 25 C using FCNTs@Ag-200 as the cathode for Na/CFx and K/CFx batteries, respectively, which is a significant improvement over the state-of-the-art. Therefore, the advanced CFx-based primary batteries developed here are promising in applications that simultaneously require fast discharge, high energy density, high power density, and long-term storage.