Anchoring ultrafine Ru nanoparticles on cotton-derived self-standing carbon fibers as efficient cathode catalyst for Li-CO battery.

Li-CO batteries could capture and convert CO into a valuable energy storage medium. The slow kinetics and high activation barrier associated with the breakdown cleavage of discharge products pose a significant hurdle in the advancement of reversible Li-CO batteries. Herein, cotton-derived self-standing carbon fibers were utilized to disperse Ru nanoparticles which could avoid depletion of active sites caused by stacking of graphite-based supports. Consequently, CBRu cathode presents small voltage polarization of 1.41 V at high current density of 200 μA cm, and high energy efficiency of 76.0 % at 20 μA cm as well as long-term cyclability over 1000 h. According to in/ex-situ characterizations and theoretical calculations, the unique cross-linked structure of the carbon fibers offers ample space for the deposition of discharge products while these ultrafine Ru nanoparticles regulate the growth path of LiCO and accelerate reaction kinetics. This study offers a novel perspective on the selection of self-standing cathode carbon matrix for Li-CO batteries.