Despite the high energy densities, lithium-sulfur (Li-S) batteries suffer from insufficient cycle life originating from the shuttling process involving lithium polysulfides (LiPSs). Various approaches have been introduced to resolve the shuttling problem, but they are not usually effective for electrodes with high sulfur contents. Here, we report an exfoliated 2D lepidocrocite titanium oxide nanosheet as a component for sulfur cathodes to suppress polysulfide dissolution markedly. In particular, the Lewis acidity originating from undercoordinated Ti species as well as the large surface area associated with the 2D structure endow 2D lepidocrocite titanium oxide with an efficient interaction with LiPSs. As a result, even with a sulfur content of 80 wt %, the Li-S cell exhibits 1023.5 mAh g-1 at 50 mA g-1 and a capacity retention of 82.3% after 300 cycles measured at 1000 mA g-1. The considerably improved cycling performance provides useful insight for designing sulfur cathodes, that is, the incorporation of acidic 2D metal oxide nanosheets.
Bibliographical noteFunding Information:
This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIP) (No. NRF-2017R1A2A1A17069463) and by the Korea government (MSIT) (No. NRF-2017R1A5A1015365). S.B.P. was supported by RP-Grant 2016 of Ewha Womans University. J.W.C. acknowledges support from the National Research Foundation of Korea (NRF) grant funded by the Korean government (MEST) (NRF-2015R1A2A1A05001737).
© 2018 American Chemical Society.
All Science Journal Classification (ASJC) codes
- Chemistry (miscellaneous)
- Renewable Energy, Sustainability and the Environment
- Fuel Technology
- Energy Engineering and Power Technology
- Materials Chemistry