Zhong Lei, Mo Yudi, Deng Kuirong, Wang Shuanjin, Han Dongmei, Ren Shan, Xiao Min, Meng Yuezhong
The Key Laboratory of Low-carbon Chemistry & Energy Conservation of Guangdong Province/State Key Laboratory of Optoelectronic Materials and Technologies, School of Materials Science and Engineering , Sun Yat-Sen University , Guangzhou 510275 , P. R. China.
School of Chemical Engineering and Technology , Sun Yat-Sen University , Zhuhai 519082 , P. R. China.
ACS Appl Mater Interfaces. 2019 Aug 14;11(32):28968-28977. doi: 10.1021/acsami.9b09604. Epub 2019 Aug 2.
A slightly cross-linked lithium borate containing single ion-conducting polymer (LBSIP) as a bifunctional binder for lithium sulfur batteries is designed and fabricated via a one-step thiol-ene click reaction. The LBSIP binder exhibits a maximum peeling strength of over 600 mN mm between the sulfur cathode and aluminum foil, together showing a high lithium ion diffusion coefficient of 2.1 × 10 cm s. Owing to the unique electron-donating groups, the binder can provide a good ionic conductive network and a dramatically enhanced polysulfide-trapping feature. The strong interaction between electron-donating groups of LBSIP with LiS was confirmed by the Li-NMR analysis and density-functional theory calculation. The cathode using the LBSIP binder exhibited a high Coulombic efficiency of ∼100% and an initial specific capacity of 712 mAh g with a capacity fading rate of 0.06% per cycle after 500 cycles at 0.5 C. Even at a high current rate of 2 C, a reversible capacity of over 500 mAh g was still obtained. However, the capacity of the cathode using the PVDF binder decreased to 331 mAh g after 180 cycles at 0.5 C. This work is very attractive for the rational design of functional binders for Li-S batteries with both ion-transporting and polysulfide-trapping features.
通过一步硫醇-烯点击反应设计并制备了一种含单离子导电聚合物的轻度交联硼酸锂（LBSIP），用作锂硫电池的双功能粘合剂。LBSIP粘合剂在硫阴极和铝箔之间表现出超过600 mN/mm的最大剥离强度，同时显示出2.1×10⁻⁵ cm²/s的高锂离子扩散系数。由于独特的供电子基团，该粘合剂可提供良好的离子导电网络和显著增强的多硫化物捕获特性。通过锂核磁共振分析和密度泛函理论计算证实了LBSIP的供电子基团与LiS之间的强相互作用。使用LBSIP粘合剂的阴极在0.5 C下500次循环后表现出约100%的高库仑效率和712 mAh/g的初始比容量，容量衰减率为每循环0.06%。即使在2 C的高电流速率下，仍可获得超过500 mAh/g的可逆容量。然而，使用聚偏氟乙烯（PVDF）粘合剂的阴极在0.5 C下180次循环后容量降至331 mAh/g。这项工作对于合理设计具有离子传输和多硫化物捕获特性的锂硫电池功能粘合剂非常有吸引力。
