Abstract：
The commercial application of lithium-sulfur batteries is primarily impeded by the constant shuttling of soluble polysulfides and sluggish redox kinetics. Nowadays, the discovery of the heterojunction, which combines materials with diverse properties, offers a new perspective for overcoming these obstacles. Herein, a functional coating separator for the lithium-sulfur battery is designed using a MnO2-ZnS p-n heterojunction with a spontaneous built-in electric field (BIEF). The MnO2 nanowire provides suitable adsorption capacity for polysulfides, while the abundant reactive sites brought by ZnS ensure efficient conversion. Moreover, the BIEF significantly facilitates the migration of electrons and polysulfides at the MnO2-ZnS interface, enabling a smooth \"adsorption-diffusion-conversion\" reaction mechanism. By serving as both the adsorption module and catalytic sites, this BIEF allows batteries utilizing separators modified with MnO2-ZnS heterojunction to achieve an impressive initial capacity of 1511.1 mAh g-1 at 0.1C and maintain a capacity decay rate of merely 0.048% per cycle at 2.0C after 1000 cycles. Even when increasing sulfur loading to 9.4 mg cm-2 in lean electrolyte (5.4 μL mg-1), the battery still exhibits an ultrahigh areal capacity of 6.0 mAh cm-2 after 100 cycles.
摘要：
锂-硫电池的商业应用主要受到可溶性多硫化物的不断穿梭和缓慢的氧化还原动力学的阻碍。如今,异质结的发现，它结合了具有不同性质的材料，为克服这些障碍提供了新的视角。在这里，使用具有自发内置电场（BIEF）的MnO2-ZnSp-n异质结来设计用于锂硫电池的功能涂层隔膜。MnO2纳米线为多硫化物提供了合适的吸附能力，而ZnS带来的丰富的活性位点保证了高效的转化。此外，BIEF显著促进电子和多硫化物在MnO2-ZnS界面的迁移，实现平稳的“吸附-扩散-转化”反应机制。通过同时充当吸附模块和催化位点，该BIEF允许电池利用用MnO2-ZnS异质结改性的隔膜,以在0.1C下实现1511.1mAhg-1的令人印象深刻的初始容量,并且在1000次循环后在2.0C下保持每个循环仅0.048%的容量衰减率。即使在稀薄电解液(5.4μLmg-1)中增加硫负荷至9.4mgcm-2,电池在100次循环后仍表现出6.0mAhcm-2的超高面积容量。
