期刊
ACS APPLIED MATERIALS & INTERFACES
卷 11, 期 5, 页码 5055-5063出版社
AMER CHEMICAL SOC
DOI: 10.1021/acsami.8b19501
关键词
lithium-sulfur batteries; TiO-TiO2 heterostructure; synergistic effect; Lewis acid-base interaction; LiPSs immobilization
资金
- Science and Technology Planning Project of Guangdong Province, China [2017B090916002]
- National Natural Science Foundation of China [51872098]
- Guangdong Natural Science Funds for Distinguished Young Scholar [2016A030306010]
- Guangdong Innovative and Entrepreneurial Research Team Program [2014ZT05N200]
- Fundamental Research Funds for Central Universities, China [2017ZX010]
Despite outstanding theoretical energy density (2600 Wh kg(-1)) and low cost of lithium-sulfur (Li-S) batteries, their practical application is seriously hindered by inferior cycle performance and low Coulombic efficiency due to the shuttle effect of lithium polysulfides (LiPSs). Herein, we proposed a strategy that combines TiO-TiO2 heterostructure materials (H-TiOx, x = 1, 2) and conductive polypyrrole (PPy) to form a multifunctional sulfur host. Initially, the TiO-TiO2 heterostructure can enhance the redox reaction kinetics of sulfur species and improve the conductivity of sulfur cathode together with the PPy coating layer. Moreover, the defect-abundant H-TiOx matrices can trap LiPSs by the formation of Ti-S bond via the Lewis acid-base interaction. Furthermore, the PPy coating can physically hinder the diffusion of LiPSs, as well as chemically adsorb LiPSs by the polar-polar mechanism. Benefiting from the synergistic effect of H-TiOx and PPy layer, the novel cathode delivered high specific capacities at different current rates (1130, 990, 932, 862, and 726 mAh g(-1) at 0.1, 0.2, 0.3, 0.5, and 1C, respectively) and an ultralow capacity decay of 0.0406% per cycle after 1000 cycles at 1C. This work can not only indicate effectiveness of employing H-TiOx materials to realize the LiPSs immobilization but also shed light on the feasibility of combining different materials to achieve the multifunctional sulfur hosts for advanced Li-S batteries.
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