Incorporation of LiF into functionalized polymer fiber networks enabling high capacity and high rate cycling of lithium metal composite anodes

Abstract Constructing a lithium metal host is an effective strategy to address the infinite volume change and subsequent vast rupture of solid electrolyte interphase (SEI) for the unsupported Li0/Li+ chemistry, whereas the controllable deposition/dissolution of lithium still need to be improved by the functionalization of the host. Herein, a 3D oxidized polyacrylonitrile fiber network incorporated with LiF (OPAN-LiF) is demonstrated to guide a bottom-up deposition of Li into a flat and dense structure well confined in the host. The oxidation process introduces polar functional groups to the fibers, rendering good wettability with the electrolyte and opulent Li+ access. The incorporation of LiF further tailors lithium deposition and inhibits the formation of dead lithium. The OPAN-LiF electrode can deliver areametric capacity up to 14 mAh cm-2 at 1 mA cm-2 and be stably cycled at current density as high as 5 mA cm-2 with 1 mAh cm-2. Coupled with LiFePO4 cathode, the full cells can present high capacity retention beyond 89% after 1600 cycles at 5 C. It is expected that the synthesized 3D functionalized composite scaffolds can be combined with other advanced electrolytes and cathodes to develop high performance lithium metal batteries.