中空金属-有机框架促进稳定和快速的锂硫电池

Hollow metal-organic framework promotes stable and fast lithium sulfur batteries

锂硫电池以其高能量密度和低成本而成为最有前途的储能系统之一。然而,锂硫电池的商业化仍然受到几个技术问题的阻碍,即严重的多硫化物穿梭和缓慢的硫转化动力学。报道了一种独特的中空MOFs来捕获和催化多硫化物,以实现高效锂硫电池。多孔中空结构不仅可以适应充放电过程中的体积变化,而且还暴露了大量的活性位点,促进了硫氧化还原反应。由于这些结构上的优势,所制备的硫电极具有良好的电化学性能,即在3 C时,800次循环后每圈的平均容量衰率为0.06%。当处于更高的4 C充放电电流时,仍然具有598 mAh/g的初始容量,循环1000圈后,每圈的平均容量衰率仅为0.07%。

Lithium-sulfur battery is one of the most promising energy storage systems because of its high energy density and low cost.However,the commercialization of lithium-sulfur batteries is still hampered by several technical problems,namely severe polysulfide shuttle and slow sulfur conversion kinetics.In this paper,we report a unique hollow MOFs to capture and catalyze polysulfide to achieve high efficiency lithium-sulfur batteries.The porous hollow structures can not only tolerate the volume change during the charging-discharging process,but also expose a large number of active sites within MOFs and promote the sulfur conversion redox.Due to these structural advantages,the prepared sulfur electrode exhibits excellent electrochemical performance.At 3 C,the average capacity decay of each cycle after 800 cycles is 0.06%.Under a higher 4 C charge/discharge current,it still has an initial capacity of 598 mAh/g,the average capacity decay per cycle is only 0.07%after 1000 cycles.