Qiu Sheng-You, Wang Chuang, Jiang Zai-Xing, Zhang Li-Su, Gu Liang-Liang, Wang Ke-Xin, Gao Jian, Zhu Xiao-Dong, Wu Gang
School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin, 150001, China.
State Key Laboratory Base of Eco-Chemical Engineering, College of Chemical Engineering, Qingdao University of Science & Technology, Qingdao, 266042, China.
Nanoscale. 2020 Aug 20;12(32):16678-16684. doi: 10.1039/d0nr03528a.
Lithium-sulfur (Li-S) batteries face a few vital issues, including poor conductivity, severe volume expansion/contraction, and especially the detrimental shuttle effect during the long-term electrochemical process. Herein, we designed a hierarchical MXene@TiO2 nanoarray via in situ solvothermal strategies followed by heat treatment. The MXene@TiO2 heterostructure achieves superior charge transfer and sulfur encapsulation. Based on the polar-polar and Lewis acid-base mechanism, the robust dual chemisorption capability to trap polysulfides can be synergistically realized through the intense polarity of TiO2 and the abundant acid metal sites of MXene. Hence, the MXene@TiO2 nanoarray as a sulfur host retains a substantially stable discharge capacity of 612.7 mA h g-1 after 500 cycles at a rate of 2 C, which represents a low fading rate of 0.058% per cycle.
锂硫（Li-S）电池面临一些关键问题，包括导电性差、严重的体积膨胀/收缩，尤其是在长期电化学过程中有害的穿梭效应。在此，我们通过原位溶剂热策略并随后进行热处理设计了一种分级MXene@TiO2纳米阵列。MXene@TiO2异质结构实现了优异的电荷转移和硫封装。基于极性-极性和路易斯酸碱机制，通过TiO2的强极性和MXene丰富的酸性金属位点，可以协同实现捕获多硫化物的强大双化学吸附能力。因此，作为硫宿主的MXene@TiO2纳米阵列在2 C倍率下500次循环后仍保持612.7 mA h g-1的基本稳定放电容量，这代表着每循环0.058%的低衰减率。
