Revealing the synergistic mechanism of multiply nanostructured V2O3 hollow nanospheres integrated with doped N, Ni heteroatoms, in-situ grown carbon nanotubes and coated carbon nanolayers for the enhancement of lithium-sulfur batteries

Lithium sulfur (Li-S) batteries are regarded as one of the most promising future energy storage candidates on account of high theoretical specific capacity of 1675 mAh g(-1) and energy density of 2600 Wh kg(-1). However, their practical application is seriously hindered due to the poor conductivity and volume expansion of sulfur, the weak redox kinetics of lithium polysulfide (LPS), and the severe shuttle effect of LPS. Herein, V2O3 @N,Ni-C nanostructures, multiply integrated with zero-dimensional (0D) V2O3 nanoparticles, 1D carbon nanotubes, 2D carbon coating layers and graphene, 3D hollow spheres, and doped N and Ni heteroatoms, were synthesized via a solvothermal method followed by chemical vapor deposition. After being used as a modifier for traditional commercial separator of Li-S batteries, the shuttle effect of LPS can be effectively suppressed owing to the abundant active physical and chemical adsorption sites derived from large specific surface area, rich porosity, and tremendous polarity of the V2O3 nanoparticles with multiple secondary nanostructure integration. Meanwhile, the transfer of Li+ ions and electrons can be effectively enhanced by the highly conductive 2D carbon network, and the kinetics of redox reaction (Li2Sn <-> Li2S) can be accelerated by the doped N and Ni heteroatoms, leading to a synergistic promotion on the reutilization of the adsorbed LPS. Additionally, the unique 3D hollow structure can not only enhance the penetration of electrolyte, but also buffer the volume expansion of sulfur to some extent. Therefore, the rate capacity and cycling performance can be significantly enhanced by the multifunction synergism of adsorption, conductivity, catalysis, and volume buffering. An initial discharge capacity of 1590.4 mAh g(-1) can be achieved at 0.1C, and the discharge capacity of 803.5 mAh g(-1) can be still exhibited when increasing to 2C. After a long period of 500 cycles, additionally, the discharge specific capacity of 1142.2 mAh g(-1) and capacity attenuation of 0.0617% per cycle can be obtained at 1C. (C) 2021 Published by Elsevier Inc.

Automated summary

A multifunctional nanostructure has been synthesized to improve the performance of lithium-sulfur batteries. The nanostructure exhibits abundant adsorption sites, high conductivity, catalytic activity, and volume buffering, effectively suppressing the shuttle effect of lithium polysulfide and enhancing the rate capacity and cycling performance of the batteries.