Liu Lantao, Li Yiming, Wang Shuaize, Lu Yaping, Zhang Jiapeng, Wang Dengke, Ding Yinghui, Qiu Daping, Niu Jin, Yu Yingchun, Chen Xiaohong, Song Huaihe
State Key Laboratory of Chemical Resource Engineering, Beijing Key Laboratory of Electrochemical Process and Technology for Materials, Beijing University of Chemical Technology, Beijing 100029, PR China.
State Key Laboratory of Chemical Resource Engineering, Beijing Key Laboratory of Electrochemical Process and Technology for Materials, Beijing University of Chemical Technology, Beijing 100029, PR China.
J Colloid Interface Sci. 2022 Dec 15;628(Pt A):975-983. doi: 10.1016/j.jcis.2022.08.007. Epub 2022 Aug 3.
S doping is an effective strategy to improve the potassium-ion storage performance of carbon-based materials. However, due to the large atomic radius of S and poor thermal stability, it is challenging to synthesize carbon materials with high sulfur content by solid-phase transformation. In this work, we designed a multi-cavity structure that can confine the molten S during heat treatment and make it fully react, then achieving high S doping (7.6 at. %). As we known, S doping can also effectively increase the active sites of carbon materials to obtain higher capacity. In addition, through different ex/in-situ characterizations and DFT calculations, we confirmed that the S atoms can effectively expand the interlayer spacing of carbon, which facilitates the intercalation/deintercalation reaction of K, thereby significantly improving the rate performance. Therefore, benefiting from the effect of S-doping, the sample exhibits high reversible specific capacity (401.0 mAh g at 0.1 A/g) and rate performance (167.2 mAh g at 5 A/g). The as-assembled K hybrid capacitor delivers both high energy density and power density (138.5 W h kg and 7692.5 W kg, respectively). This work provides a new approach to design S content carbon-based materials for high performance K storage.
硫掺杂是提高碳基材料钾离子存储性能的有效策略。然而，由于硫的原子半径大且热稳定性差，通过固相转变合成高硫含量的碳材料具有挑战性。在这项工作中，我们设计了一种多腔结构，该结构可以在热处理过程中限制熔融硫并使其充分反应，从而实现高硫掺杂（7.6原子%）。众所周知，硫掺杂还可以有效地增加碳材料的活性位点以获得更高的容量。此外，通过不同的原位/非原位表征和密度泛函理论计算，我们证实硫原子可以有效地扩大碳的层间距，这有利于钾离子的嵌入/脱嵌反应，从而显著提高倍率性能。因此，受益于硫掺杂的作用，该样品表现出高可逆比容量（在0.1 A/g时为401.0 mAh/g）和倍率性能（在5 A/g时为167.2 mAh/g）。组装后的钾混合电容器具有高能量密度和功率密度（分别为138.5 W h/kg和7692.5 W/kg）。这项工作为设计用于高性能钾存储的高硫含量碳基材料提供了一种新方法。
