Zhang Jianli, Cheng Yun, Chen Haibo, Wang Yang, Chen Qiang, Hou Guangya, Wen Ming, Tang Yiping
College of Materials Science and Engineering, Zhejiang University of Technology, Hangzhou 310014, P. R. China.
State Key Laboratory of Advanced Technologies for Comprehensive Utilization of Platinum Metals, Kunming Institute of Precious Metals, Kunming, Yunnan 650106, China.
ACS Appl Mater Interfaces. 2022 Apr 13;14(14):16289-16299. doi: 10.1021/acsami.2c02212. Epub 2022 Mar 31.
Lithium-sulfur batteries (LSBs) have the advantages of high energy density and low cost and are considered promising next-generation energy storage systems, but the shuttle effect and slow sulfur redox kinetics severely limit their practical applications. Herein, MoP quantum dot-modified N,P-doped hollow PPy substrates are adopted as separator modification coatings for LSBs. The MoP quantum dots exhibit excellent chemisorption and catalytic conversion capabilities for polysulfides, while the N,P-doped PPy substrates can provide flexible channels for Li/electron transport and act as a physical barrier to suppress the shuttle effect. As a result, LSBs assembled with modified separators exhibit excellent rate capability (739 mAh/g at 3 C) and cycle performance (600 mAh/g at 1 C after 600 cycles, 0.052% decay per cycle). Moreover, even under a high sulfur loading of 3.68 mg/cm, areal capacities of 3.58 and 2.92 mAh/cm for the 1st cycle and 110th cycle are achieved. In addition, according to density functional theory calculations, MoP quantum dots have large adsorption energy for S and LiS, which further confirms the possibility of lowering the initial nucleation energy barrier of LiS and helps to improve the kinetics of the subsequent LiS reaction. This study proposes a novel method for using transition-metal phosphides as catalysts in high-performance LSBs.
锂硫电池（LSBs）具有高能量密度和低成本的优点，被认为是很有前景的下一代储能系统，但穿梭效应和缓慢的硫氧化还原动力学严重限制了它们的实际应用。在此，采用MoP量子点修饰的N、P掺杂空心聚吡咯（PPy）基底作为锂硫电池的隔膜修饰涂层。MoP量子点对多硫化物表现出优异的化学吸附和催化转化能力，而N、P掺杂的PPy基底可为Li/电子传输提供灵活通道，并作为物理屏障抑制穿梭效应。结果，采用修饰隔膜组装的锂硫电池表现出优异的倍率性能（3 C时为739 mAh/g）和循环性能（1 C下600次循环后为600 mAh/g，每次循环衰减0.052%）。此外，即使在3.68 mg/cm²的高硫负载下，首次循环和第110次循环的面积容量分别达到3.58和2.92 mAh/cm²。此外，根据密度泛函理论计算，MoP量子点对S和LiS具有较大的吸附能，这进一步证实了降低LiS初始成核能垒的可能性，并有助于改善后续LiS反应的动力学。本研究提出了一种在高性能锂硫电池中使用过渡金属磷化物作为催化剂的新方法。
