Benzene-1,2-dithiolato complexes as cathode materials for rechargeable lithium batteries

Organosulfides are a class of promising cathode materials for rechargeable lithium batteries. In order to overcome their disadvantages of solubility and low mass density, we prepare benzene-1,2-dithiolato complexes with metal ions (Sn4+ and Cu2+) by a facile method, which are designated as Sn-(BDT) 2 and Cu-BDT, respectively. The synthesized compounds are colored solids and insoluble in liquid ether electrolyte. Their mass densities are about 2.0 mg cm(-3), which are much higher than that (1.2 mg cm(-3)) of the starting material 1,2-benzenedithiol. When evaluated in Li half cells, Sn-(BDT)(2) delivers a capacity of 221.2 mAh g(-1) rendering a volumetric energy density of 973.2 Wh L-1. Cu-BDT can deliver a capacity of 234.2 mAh g(-1) and its volumetric energy density is 1044.5 Wh L-1. Both volumetric capacities and energy densities are higher than those of the starting material. In the discharge, the metal ions serve as electron receptors and 1,2-benzenedithiolate holds lithium ions. The separate electron/lithium ion storage process is highly reversible, which is evidenced by the cycling performances of 200 and 500 cycles for the Li/Sn-(BDT)(2) and Li/Cu-BDT cells, respectively. This strategy is promising to overcome the intrinsic disadvantages of organosulfides as cathode materials for lithium batteries. (C) 2021 Elsevier Ltd. All rights reserved.

Automated summary

By incorporating metal ions with benzene-1,2-dithiolato complexes as cathode materials, the lithium batteries can achieve higher mass density and energy density, as well as improved cycling performance. This strategy shows promise in overcoming the disadvantages of organosulfides as cathode materials.