Modified Separator Using Thin Carbon Layer Obtained from Its Cathode for Advanced Lithium Sulfur Batteries.

The realization of a practical lithium sulfur battery system, despite its high theoretical specific capacity, is severely limited by fast capacity decay, which is mainly attributed to polysulfide dissolution and shuttle effect. To address this issue, we designed a thin cathode inactive material interlayer modified separator to block polysulfides. There are two advantages for this strategy. First, the coating material totally comes from the cathode, thus avoids the additional weights involved. Second, the cathode inactive material modified separator improve the reversible capacity and cycle performance by combining gelatin to chemically bond polysulfides and the carbon layer to physically block polysulfides. The research results confirm that with the cathode inactive material modified separator, the batteries retain a reversible capacity of 644 mAh g(-1) after 150 cycles, showing a low capacity decay of about 0.11% per circle at the rate of 0.5C.

Multidimensional Polycation ß-Cyclodextrin Polymer as an Effective Aqueous Binder for High Sulfur Loading Cathode in Lithium-Sulfur Batteries.

Although the lithium-sulfur battery has attracted significant attention because of its high theoretical energy density and low cost of elemental sulfur, its real application is still hindered by multiple challenges, especially the polysulfides shuttled between the cathode and anode electrodes. By originating from ß-cyclodextrin and introducing a quaternary ammonium cation into ß-cyclodextrin polymer, a new multifunctional aqueous polycation binder (ß-CDp-N(+)) for the sulfur cathode is obtained. The unique hyperbranched network structure of the new binder ß-CDp-N(+) as well as its multidimensional noncovalent interactions and the introduced cations endowed ß-CDp-N(+) with some new abilities: a sulfur-electrode-stabilized ability, a polysulfides-immobilized ability, and a volume-accommodated ability, which help to ease the primary problems of the lithium-sulfur battery, i.e., the shuttle of polysulfides and the volume change of the sulfur during charge and discharge. It is demonstrated that cycling performance and rate capability of the cathodes can be the improved by using ß-CDp-N(+) as the binder compared to other well-known binders. Even with high sulfur loading of 5.5 mg cm(-2), the cathode with ß-CDp-N(+) still can deliver an areal capacity of 4.4 mAh cm(-2) at 50 mA g(-1) after 45 cycles, which is much higher than that achieved using the cathode with the conventional binder (0.9 mAh cm(-2)).

A lithium-sulfur cathode with high sulfur loading and high capacity per area: a binder-free carbon fiber cloth-sulfur material.

A sulfur cathode with high capacity per area (>7 mA h cm(-2)) and high sulfur loading (6.7 mg cm(-2)) was fabricated by synthesizing a carbon fiber cloth-sulfur composite via a simple method. It is worth noting that an ingenious method is adopted which can improve the performance of Li-S batteries by forming in situ polysulfide ions.

A multi-core-shell structured composite cathode material with a conductive polymer network for Li-S batteries.

A multi-core-shell with a conductive network structured C-PANI-S@PANI composite with high sulfur content up to 87% was synthesized. The composite cathode delivers higher specific capacity and excellent cycle stability, retaining a reversible discharge capacity of 835 mA h g(-1) after 100 cycles when the sulfur loading of the cathode was above 6 mg cm(-2).