Researchers at Shanghai Jiao Tong University have developed a gel-like electrolyte induced by fumed alumina for dendrite-free Li deposition, lower over-potential and better cycle stability in lithium-sulfur batteries. An open-access paper on their work is published in the RSC journal Chemical Communications.

The Li-S@pPAN cells with the proposed electrolyte exhibit outstanding cycle stability and rate performance with capacity retentions of 95.1% after 300 cycles and 76.5% at 10C against 1C respectively.

In addition, the gel-like electrolyte endows the cell with a potential advantage as to safety issues such as liquid leakage and short-circuit induced by lithium dendrites.

Compared with the state-of-the-art Li-ion batteries, lithium- sulfur (Li-S) battery possesses remarkably higher theoretical specific capacity of 1675 mAh g^-1 and specific energy density of 2600 Wh kg^-1, regarded as the most promising candidate for the next generation of lithium batteries. However, there have been several critical technical issues hindering its practical application. The growth of the Li dendrites not only decays the performance of batteries but also leads to potential safety hazard. On the other hand, as the solid electrolyte interphase (SEI) formed through the slight reaction with organic electrolyte is less stable, the breakage and regeneration of the SEI are often inevitable during cycling, further resulting in the low Coulombic efficiency and rapid capacity fading. Hence, it is necessary to address these issues prior to its large-scale commercialization.

… As we know, alumina has been applied as filler in polymer electrolytes to increase overall conductivity and decrease the crystallization like silica filler. What is more, fumed alumina, like other ceramic fillers, is able to scavenge impurities such as O₂ and H₂O. Herein, fumed alumina nanoparticles are chosen for the first time to prepare a gel-like carbonate electrolyte (LiPF₆/EC-DMC) used in Li-S@pPAN cells. The significantly improved electrochemical performance is achieved and the function mechanism is revealed.

—Lei et al.

Resources

• Bin Lei, Jun Yang, Zhixin Xu, Shasha Su, Dong Wang, Jinhua Jiang and Jing Feng (2018) “Fumed alumina induced gel-like electrolyte for great performance improvement of lithium-sulfur battery” Chem. Commun. doi: 10.1039/C8CC07741J