State Key Laboratory for Modification of Chemical Fibers and Polymer Materials , Donghua University , Shanghai 200051 , P. R. China.
ACS Appl Mater Interfaces. 2018 Jun 13;10(23):19311-19317. doi: 10.1021/acsami.8b03830. Epub 2018 May 30.
Lithium-sulfur batteries have been regarded as promising candidates for energy storage because of their high energy density and low cost. It is a main challenge to develop long-term cycling stability battery. Here, a catalytic strategy is presented to accelerate reversible transformation of sulfur and its discharge products in lithium-sulfur batteries. This is achieved with single-atomic iron active sites in porous nitrogen-doped carbon, prepared by polymerizing and carbonizing diphenylamine in the presence of iron phthalocyanine and a hard template. The Fe-PNC/S composite electrode exhibited a high discharge capacity (427 mAh g) at a 0.1 C rate after 300 cycles with the Columbic efficiency of above 95.6%. Besides, the electrode delivers much higher capacity of 557.4 mAh g at 0.5 C over 300 cycles. Importantly, the Fe-PCN/S has a smaller phase nucleation overpotential of polysulfides than nitrogen-doped carbon alone for the formation of nanoscale of LiS as revealed by ex situ SEM, which enhance lithium-ion diffusion in LiS, and therefore a high rate performance and remarkable cycle life of Li-sulfur batteries were achieved. Our strategy paves a new way for polysulfide conversion with atomic iron catalysis to exploit high-performance lithium-sulfur batteries.
锂硫电池因其高能量密度和低成本而被视为有前途的储能候选物。开发长期循环稳定性电池是一个主要挑战。在这里，提出了一种催化策略来加速锂硫电池中硫及其放电产物的可逆转化。这是通过在铁酞菁和硬模板存在下聚合和碳化二苯胺来制备的具有多孔氮掺杂碳中的单原子铁活性位来实现的。Fe-PNC/S 复合电极在 300 次循环后以 0.1 C 的倍率表现出 427 mAh g 的高放电容量，库仑效率高于 95.6%。此外，该电极在 300 次循环中以 0.5 C 的速率可提供更高的容量 557.4 mAh g。重要的是，与单独的氮掺杂碳相比，Fe-PCN/S 具有较小的多硫化物成核过电位，有利于形成纳米级 LiS，从而提高了 LiS 中的锂离子扩散，因此实现了高倍率性能和出色的锂硫电池循环寿命。我们的策略为利用原子铁催化进行多硫化物转化开辟了一条新路，以开发高性能锂硫电池。
