Preparation and Electrochemical Properties of Freestanding Flexible S/CNT/NiO Electrodes for Li-S Batteries

Porous NiO synthesized via hydrothermal synthesis was used in the electrodes of lithium-sulfur batteries to inhibit the elution of lithium polysulfide. The electrode of the lithium-sulfur battery was manufactured as a freestanding flexible electrode using an economical and simple vacuum filtration method without a current collector and a binder. The porous NiO-added S/CNT/NiO electrode exhibited a high initial discharge capacity of 877 mA h g(-1) (0.2 C), which was 125 mA h g(-1) higher than that of S/CNT, and also showed excellent retention of 84% (S/CNT: 66%). This is the result of suppressing the dissolution of lithium polysulfide into the electrolyte by the strong chemical bond between NiO and lithium polysulfide during the charging and discharging process. In addition, for the flexibility test of the S/CNT/NiO electrode, the 1.6 x 4 cm(2) pouch cell was prepared and exhibited stable cycle characteristics of 620 mA h g(-1) in both the unfolded and folded state.