A long-life Li-S battery enabled by a cathode made of well-distributed B4C nanoparticles decorated activated cotton fibers

The commercialization of Li-S batteries is impeded by their short lifespan and poor rate capability resulting from the shuttle effect and sluggish reaction kinetics. Herein, we develop a bi-functional cathode substrate for Li-S batteries made of well-distributed boron carbide nanoparticles decorated activated cotton fiber (B4C-ACF), in which B4C nanoparticles serve as not only robust chemically anchoring sites to trap the polysulfides, but also afford abundant active sites for efficient sulfur conversion reactions. Meanwhile, the ACF network provides fast electron pathways for the conversion reactions and acts as the current collector. As a result, the novel cathode substrate enables a Li-S battery to deliver an initial capacity of as high as 1415 mAh g(-1) at 0.1 C, and an extrahigh reversible capacity of 928 mAh g(-1) at 3 C with an areal sulfur loading of 3.0 mg cm(-2). More strikingly, the B4C-ACF substrate-based battery could be stably operated for 3000 cycles with a high coulombic efficiency of 99.24% and a capacity decay rate of as low as 0.012% per cycle at 1 C, demonstrating that the B4C-ACF substrate holds great potential in realizing the mass production of advanced Li-S batteries.