College of Chemistry, Zhengzhou University, Zhengzhou 450001, China.
College of Science, Henan Agricultural University, Zhengzhou 450002, China.
J Colloid Interface Sci. 2023 Mar;633:1042-1053. doi: 10.1016/j.jcis.2022.12.010. Epub 2022 Dec 9.
Because of its high theoretical capacity and energy density, the lithium-sulfur (Li-S) battery is a desirable next-generation energy storage technology. However, the shuttle effect of lithium polysulfide and the slow sulfur reaction kinetics remain significant barriers to Li-S battery application. In this work, tantalum trisulfide (TaS) and selective manganese-doped tantalum trisulfide (Mn-TaS) nanocomposites on reduced graphene oxide surface were developed via a one-step hydrothermal method for the first time and introduced as a novel multifunctional mediator in the Li-S battery. The surface engineering of Mn-TaS@rGO with abundant defects not only exhibits the strong adsorption performance on lithium polysulfides (LiPSs) but also demonstrates the remarkable electrocatalytic effect on both the LiPSs conversion reaction in symmetric cell and the LiS nucleation/dissolution processes in potentiostatic experiments, which would substantially promote the electrochemical performance of LSB. The cell assembled with Mn-TaS@rGO/PP modified separator could significantly improve the cell conductivity and effectively accelerate the redox conversion of active sulfur during the charging/discharging process, which delivers exceptional long-term cycling with 683 mA h g retention capacity after the 1000th cycle at 0.3C under the sulfur loading of 2.7 mg cm. Even at the E/S ratio as low as 5.0 µL mg, the reversible specific capacity of 692 mA h g can be offered at 0.2C over 300 cycles. This research indicates that the novel Mn-TaS@rGO multifunctional mediator is successfully fabricated and applied in Li-S batteries with extraordinary electrochemical performances and gives a strategy to explore the construction of a modified functional separator.
由于其高理论容量和能量密度，锂硫（Li-S）电池是一种理想的下一代储能技术。然而，多硫化锂的穿梭效应和缓慢的硫反应动力学仍然是 Li-S 电池应用的重大障碍。在这项工作中，通过一步水热法首次开发了在还原氧化石墨烯表面上的三氧化二钽（TaS）和选择性锰掺杂三氧化二钽（Mn-TaS）纳米复合材料，并将其作为 Li-S 电池中的新型多功能介体引入。Mn-TaS@rGO 的表面工程具有丰富的缺陷，不仅对多硫化锂（LiPSs）表现出强烈的吸附性能，而且对对称电池中 LiPSs 转化反应和恒电位实验中 LiS 成核/溶解过程表现出显著的电催化作用，这将极大地促进 LSB 的电化学性能。用 Mn-TaS@rGO/PP 修饰的分离器组装的电池可以显著提高电池的导电性，并在充电/放电过程中有效地加速活性硫的氧化还原转化，在 0.3C 下，硫负载量为 2.7mg cm 时，经过 1000 次循环后，可保持 683 mA h g 的保留容量，具有出色的长期循环性能。即使在 E/S 比低至 5.0 µL mg 的情况下，在 0.2C 下也可以提供 692 mA h g 的可逆比容量，循环 300 次。这项研究表明，成功制备了新型 Mn-TaS@rGO 多功能介体，并将其应用于具有非凡电化学性能的 Li-S 电池中，为探索改性功能分离器的构建提供了一种策略。
