Key Lab for Special Functional Materials of Ministry of Education, National & Local Joint Engineering Research Center for High-efficiency Display and Lighting Technology, School of Materials Science and Engineering, Collaborative Innovation Center of Nano Functional Materials and Applications, Henan University, Kaifeng, 475004, P. R. China.
Small. 2023 Jul;19(28):e2301344. doi: 10.1002/smll.202301344. Epub 2023 Mar 27.
The construction of high sulfur (S) loading cathode is one of the critical parameters to obtain lithium-sulfur (Li-S) batteries with high energy density, but the slow redox reaction rate of high S loading cathode limits the development process. In this paper, a metal coordinated polymer-based three-dimensional network binder, which can improve the reaction rate and stability of S electrode. Compared with traditional linear polymer binders, the metal coordinated polymer binder can not only increase the load amount of S through the three-dimensional cross-linking, but also promote the interconversion reactions between S and lithium sulfide (Li S), avoiding the passivation of electrode and improving the stability of the positive electrode. At an S load of 4-5 mg cm and an E/S ratio of 5.5 µL mg , the discharged voltage in the second platform is 2.04 V and the initial capacity is 938 mA h g with metal coordinated polymer binder. Moreover, the capacity retention rate approaches 87% after 100 cycles. In comparison, the discharged voltage in the second platform is lost and the initial capacity is 347 mA h g with PVDF binder. It demonstrates the advanced properties of metal-coordinated polymer binders for improving the performance of Li-S batteries.
高硫（S）负载阴极的构建是获得高能量密度锂硫（Li-S）电池的关键参数之一，但高 S 负载阴极的缓慢氧化还原反应速率限制了其发展进程。本文提出了一种基于金属配位聚合物的三维网络粘结剂，该粘结剂可以提高 S 电极的反应速率和稳定性。与传统的线性聚合物粘结剂相比，金属配位聚合物粘结剂不仅可以通过三维交联增加 S 的负载量，还可以促进 S 和硫化锂（Li 2 S）之间的转化反应，避免电极的钝化，提高正极的稳定性。在 S 负载量为 4-5 mg cm 和 E/S 比为 5.5 µL mg 的情况下，采用金属配位聚合物粘结剂的电池在第二平台的放电电压为 2.04 V，初始容量为 938 mA h g。此外，经过 100 次循环后，容量保持率接近 87%。相比之下，采用 PVDF 粘结剂的电池在第二平台的放电电压丢失，初始容量为 347 mA h g。这表明金属配位聚合物粘结剂在提高 Li-S 电池性能方面具有先进的性能。
