Boron nitride wrapped N-doped carbon nanosheet as a host for advanced lithium-sulfur battery

Sandwich structure of boron nitride (BN) nanocrystals wrapped with uniform interconnected N-doped carbon nanosheets (N-CNs) is prepared as a lithium-sulfur battery cathode material to overcome the sluggish redox reaction and severe shuttle effect of lithium polysulfides (LiPSs). The BN@N-CNs-2/S presents outstanding rate capacity of 528 mAh g(-1) at 2 A g(-1), with extended cycle life and sluggish capacity decrease rate of 0.026% per cycle at 2 A g(-1) for more than 1000 cycles. Such high performance is a result of the unique sandwich structure of BN nanocrystals evenly compounded on N-CNs, which leads to uniform distribution of active sulfur species and effectively alleviates volume expansion in the cycling process. The BN@N-CNs sandwich structure possesses the key advantages of high conductivity of N-CNs, strong chemisorption and catalytic effect for LiPSs, which is demonstrated by theoretical calculations and cyclic voltammetry curves of the symmetrical cells.

Automated summary

The sandwich structure of boron nitride nanocrystals wrapped with N-doped carbon nanosheets in this study provides a solution to the sluggish redox reaction and shuttle effect in lithium-sulfur battery cathodes. This innovative design allows for uniform distribution of active sulfur species, effectively mitigating volume expansion during cycling and achieving high performance.