Original Article:
Metal iodides (LiI, MgI2, AlI3, TiI4, and SnI4) potentiality as electrolyte additives for Li-S batteries
Sollee Kim, et al.
Electrochimica Acta, 2021, 391, 138927.
10.1016/j.electacta.2021.138927
In lithium-sulfur (Li-S) battery research, electrolyte additives are used to suppress soluble lithium polysulfides and stabilize the lithium electrode/electrolyte interface to mitigate the failure of lithium-sulfur batteries. Interestingly, although lithium halide salts such as LiF, LiCl, LiBr, and LiI are neither good sources of electrons nor good conductors of ions, they have been investigated as additives to form stable solid electrolyte interface (SEI) layers. Because they work by increasing the diffusion rate of Li ions through the SEI.
In this work, the authors investigated the effect of various metal iodides (namely, LiI, MgI2,AlI3, TiI4, and SnI4) as electrolyte additives on the electrochemical performance of Li-S batteries. Theoretically, these metal iodide electrolyte additives can suppress the Li polysulfide redox shuttling effect and modify the interface between the electrolyte and the Li anode.
Research Points
1. Not all metal complexes with iodide anion can form a stable SEI layer on Li metal.
2. Iodide ions increase the viscosity of the electrolyte through the polymerization of ether solvents to inhibit the polysulfide shuttling reaction, but may also reduce the electrochemical performance of the battery by interfering with the conductivity and diffusion of lithium ions.
3. It is possible to form an alloy phase with Li, and depositing metal elements helps to form a stable SEI on Li metal.
4. Electrolytes containing LiI or MgI2 additives in particular show high ionic conductivity and usable low viscosity.
Chemicals Related in the Paper:
| Catalog Number | Product Name | Structure | CAS Number | Price |
|---|---|---|---|---|
| ACM7784238 | Aluminum iodide |  |
7784-23-8 | Price |
| ACM10377512 | Lithium Iodide |  |
10377-51-2 | Price |
| ACM10377589 | Magnesium iodide |  |
10377-58-9 | Price |
| ACM13840454 | TITANIUM IODIDE |  |
13840-45-4 | Price |
