Xing Zhenyu, Tan Guoqiang, Yuan Yifei, Wang Bao, Ma Lu, Xie Jing, Li Zesheng, Wu Tianpin, Ren Yang, Shahbazian-Yassar Reza, Lu Jun, Ji Xiulei, Chen Zhongwei
Department of Chemical Engineering, Waterloo Institute for Nanotechnology, Waterloo Institute for Sustainable Energy, University of Waterloo, Waterloo, Ontario, N2L 3G1, Canada.
Department of Chemistry, Oregon State University, Corvallis, OR, 97331, USA.
Adv Mater. 2020 Aug;32(31):e2002403. doi: 10.1002/adma.202002403. Epub 2020 Jun 25.
Li S holds a promising role as a high-capacity Li-containing cathode, circumventing use of metallic lithium in constructing next-generation batteries to replace current Li-ion batteries. However, progress of Li S cathode has been plagued by its intrinsic drawbacks, including high activation potentials, poor rate performance, and rapid capacity fading during long cycling. Herein, a series of Li S/transition metal (TM) nanocomposites are synthesized via a lithiothermic reduction reaction, and it is realized that the presence of TMs in Li S matrix can transform electrochemical behaviors of Li S. On the one hand, the incorporation of W, Mo, or Ti greatly increases electronic and ionic conductivity of Li S composites and inhibits the polysulfide dissolution via the TMS bond, effectively addressing the drawbacks of Li S cathodes. In particular, Li S/W and Li S/Mo exhibit the highest ionic conductivity of solid-phase Li-ion conductors ever-reported: 5.44 × 10 and 3.62 × 10 S m , respectively. On the other hand, integrating Co, Mn, and Zn turns Li S into a prelithiation agent, forming metal sulfides rather than S after the full charge. These interesting findings may shed light on the design of Li S-based cathode materials.
硫化锂作为一种高容量含锂正极材料具有广阔的应用前景，可避免在构建下一代电池时使用金属锂来替代目前的锂离子电池。然而，硫化锂正极的发展一直受到其固有缺点的困扰，包括高活化电位、较差的倍率性能以及在长时间循环过程中快速的容量衰减。在此，通过锂热还原反应合成了一系列硫化锂/过渡金属（TM）纳米复合材料，并且发现硫化锂基体中过渡金属的存在可以改变硫化锂的电化学行为。一方面，钨、钼或钛的引入极大地提高了硫化锂复合材料的电子和离子导电性，并通过TM-S键抑制多硫化物的溶解，有效解决了硫化锂正极的缺点。特别是，硫化锂/钨和硫化锂/钼展现出有史以来报道的固相锂离子导体的最高离子电导率：分别为5.44×10和3.62×10 S m。另一方面，整合钴、锰和锌可使硫化锂成为一种预锂化剂，在完全充电后形成金属硫化物而非硫。这些有趣的发现可能为基于硫化锂的正极材料设计提供启示。
