Interface-reinforced high-capacity fiber cathode for wearable Li-S batteries

Fiber-shaped Li-S batteries are attractive for constructing smart textiles as flexible power solutions due to their high theoretical specific capacity, flexibility and wearability. However, severe interfacial issues, such as the shuttle effect of polysulfides on the cathode side, lead to capacity decay and poor lifespan of the batteries. Herein, we report a fiber-shaped composite cathode with collaborative interface interactions to maintain electrode integrity and boost electrochemical performance. In this architecture, nanosulfur-polyvinylpyrrolidone (nanoS-PVP) particles are uniformly implanted into the few-layer Ti₃C₂T with outstanding electrical conductivity and then coated on aluminum (Al) fiber current collectors. Impressively, nanoS and soluble polysulfides are restricted to the cathode side via synergy physical confinement and chemical adsorption of Ti₃C₂T . The PVP chains on the surface of the nanoS prevent the sulfur from agglomeration and bridge the Ti₃C₂T by abundant hydrogen bonds. The enhanced interface endows the cathode with excellent mechanical flexibility, good adsorption of polysulfides and fast reaction kinetics. Consequently, the prepared Ti₃C₂T /nanoS-PVP@Al cathode exhibits excellent cycling performance (capacity retention of 92.8% after 1000 cycles at 1 C), high-rate capacity (556.2 mAh g^-1 at 2.0 C) and high linear capacity (22.9 mAh m^-1). Additionally, the fiber-shaped Li-S battery works effectively under deformation and high/low-temperature conditions. It can be integrated into the fabric to power light emitting diodes or charge a smartphone wirelessly.