A Ti₃C₂@CF sulfur host material has been prepared by enveloping 3D carbon fibers (CFs) with isolated 2D ultrathin Ti₃C₂ nanosheets, which largely avoids the restacking of the nanosheets and significantly improves the exposure degree of the 2D surface. This material allows uniform thin-layer loading of sulfur at a high density of 4 mg cm⁻² without loss of electrode conductivity. The Ti₃C₂ nanosheets form strong bonding with lithium polysulfides to inhibit shuttling. Also, the flexible enveloping Ti₃C₂ greatly enhances the ductility of CFs, which successfully withstands the stress and distortion caused by volume expansion, and thus avoids the pulverization of the cathode. The resulting Li–S battery exhibits remarkable cycling stability, a negligible capacity fading rate (0.06% per cycle over the first 200 cycles at 0.5C) and a greatly retained cycling capacity (626.0 mA h g⁻¹ after 1000 cycles at 1C).

中文翻译：

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碳纤维包封超薄Ti3C2纳米片：高密度负载硫的锂硫电池正极，具有出色的循环稳定性

通过用隔离的2D超薄Ti ₃ C ₂纳米片包裹3D碳纤维（CFs），制备了Ti ₃ C ₂ @CF硫基质材料，这在很大程度上避免了纳米片的重新堆叠，并显着提高了2D表面的暴露程度。该材料允许以4mg cm ^-2的高密度均匀地薄薄地装载硫，而不会损失电极电导率。Ti ₃ C ₂纳米片与多硫化锂形成牢固的结合，从而抑制穿梭。另外，柔性包封的Ti ₃ C ₂大大提高了CFs的延展性，成功地承受了体积膨胀引起的应力和变形，从而避免了阴极的粉化。所得的Li–S电池具有出色的循环稳定性，可忽略的容量衰减率（在0.5C的前200个循环中，每个循环为0.06％）和极大保留的循环容量（在1C的1000个循环后为626.0 mA hg ^-1）。