Multiple structure integrations of embedded-Co and coated-TiO2 nanoparticles in N, Co-codoped carbon nanotubes for high efficiency lithium-sulfur batteries

Abstract

Lithium-sulfur (Li-S) battery is considered as one of the most prospective energy storage devices; nevertheless, its application is seriously impeded owing to lithium polysulfide (LPS) shuttle, volume expansion, poor conductivity of sulfur, and weak redox kinetics between various LPSs. Herein, multiple-structure nanohybrids (CNT/N-Co@TiO2), integrated with zero-dimensional (0D) embedded-Co and coated-TiO2 nanoparticles, 1D carbon nanotubes, quasi-2D carbon nanolayer, 3D spherical networks, and N, Co-codoped heteroatoms, are synthesized. The multifunction synergism of improved adsorption, effective expansion buffering, excellent conductivity and efficient catalysis observably strengthens battery performance with CNT/N-Co@TiO2-modified separator. An initial discharge capacity of 1320 mAh g−1 can achieve at 0.2C, and meanwhile an initial discharge capacity of 1051 mAh g−1 can acquire with 0.071% capacity decay rate per cycle over 500 cycles at 1C. An initial specific discharge capacity of 653 mAh g−1 can show at 3C. Impressively, even at 5.1 mg cm−1 high sulfur loading, a distinguished cycling stability of 640 mAh g−1 can maintain after 60 cycles at 0.1C. This work demonstrates that high efficiency Li-S batteries can be implemented via a multifunction synergism of multiple-structure nanohybrids integrated with high conductivity carbon, polar metal oxide, and high catalytic activity embedded and coated nanoparticles and doped heteroatoms.