Efficient Anchoring of Polysulfides Based on Self-Assembled Ti3C2Tx Nanosheet-Connected Hollow Co(OH)2 Nanotubes for Lithium-Sulfur Batteries.

Designing sulfur host materials with unique functions such as physical constraint or chemical catalysis to suppress the shuttle effect and promote the fast conversion of polysulfides is a prerequisite for lithium-sulfur batteries (LSBs). Herein, we construct hollow Co(OH)2 nanotubes connected by Ti3C2Tx nanosheets (denoted as Co(OH)2@Ti3C2Tx) as host materials for sulfur through a simple self-assembly method at room temperature. The large void spaces of Co(OH)2 nanotubes not only confine higher sulfur loading but also mitigate the volumetric expansion in the process of lithiation. Moreover, the conductive Ti3C2Tx layers facilitate fast electron transfer and catalyze the transition of sulfur based on the terminations on the surface. Combining those two materials can also act as an efficient polysulfide anchor to enable outstanding electrochemical performance. The Co(OH)2@Ti3C2Tx@S cathode presents a high discharge capacity of 1400 mAh g-1 at 0.1C and long-cycling stability at 1C for 500 cycles. Moreover, the obtained capacity of Li2S precipitation and the dissolution capacity reach 193.3 and 291.1 mAh g-1, respectively. Consequently, this work demonstrates a facile strategy to design multifunctional materials that effectively confine the polysulfides and enhance the performance of LSBs.