Decorating highly efficient VN quantum dots onto N-doped hollow carbon nanospheres enables effective inhibition of the shuttle effect and acceleration of LiPSs conversion in lithium–sulfur batteries

Lithium-sulfur battery (LSB) is renowned for its high energy density storage property yet its development has faced significant challenges including the shuttle effect and slow reaction rates. A vanadium nitride quantum dots decorated N-doped hollow carbon nanosphere (VN@CS) is thus synthesized and applied as the sulfur host material in LSBs. Experimental results demonstrate the efficient adsorption and catalytic conversion character of the polar VN for soluble lithium polysulfides (LiPSs), contributing to an effective inhibition of the shuttle effect and acceleration of LiPSs conversion. Consequently, the S/VN@CS cathode exhibits a high specific capacity of 849.1 mA h g −1 at a high current density of 4 C, along with the long cycling performance, achieving 1000 cycles with a low capacity decay rate of 0.038% per cycle at 2 C. The work presents the successful combination of small yet highly efficient quantum dots with a conductive substrate to achieve excellent electrochemical performances of LSBs.