Single-atom tailoring of Li2S to Form Li2S2 for building better lithium-sulfur batteries

The Li2S-based cathodes to couple with Li-free anodes are regarded as a commercially available approach to overcome the safety risk of lithium metal anodes. However, the passivated Li2S instinct leads to a high activation potential in the initial charging process, and the notorious shuttle effect of polysulfide is inevitable upon cell cycling. Here we create a single atom tailoring strategy by comproportionation reactions (Li2S + 1/8S(8) = Li2S2) to form the Li2S2 materials without any complex manufacturing process or additives, where the Li2S2 cell enables a lower potential barrier and allows for the 3.0 V activation voltage without any other material modification. Meanwhile, the polar conducting material TaB2 is introduced to restrain the migration of polysulfides, and provide fast redox reaction kinetics. With those ingenious tailoring of cell designs, the Li2S2-TaB2 cell (Li2S2: 88 wt%) exhibits high areal capacity (4.6 mAh/cm(2) at 6.0 mg/cm(2) Li2S2 loading), excellent cycling stability (500 cycles at 1.6 mA/cm(2)).

Automated summary

This paper presents a method for preparing Li2S2 materials by using the reaction of Li2S + 1/8S(8) = Li2S2, and introduces the polar conducting material TaB2 to improve the electrochemical performance and safety of the battery.