State Key Laboratory for Physical Chemistry of Solid Surfaces, Department of Chemistry, College of Chemistry and Chemical Engineering, iChem (Collaborative Innovation Center of Chemistry for Energy Materials) Xiamen , Fujian, 361005, China.
ACS Nano. 2017 Jun 27;11(6):6031-6039. doi: 10.1021/acsnano.7b01945. Epub 2017 Jun 7.
High utilization and loading of sulfur in cathodes holds the key in the realization of Li-S batteries. We here synthesized a CoN mesoporous sphere, which was made up of nanosheets, via an easy and convenient method. This material presents high affinity, speedy trapping, and absorbing capacity for polysulfides and acts as a bifunctional catalysis for sulfur redox processes; therefore it is an ideal matrix for S active material. With such a mesoporous sphere used as a sulfur host in Li-S batteries, extraordinary electrochemistry performance has been achieved. With a sulfur content of 72.3 wt % in the composite, the CoN@S delivered a high specific discharge capacity of 1659 mAh g at 0.1 C, almost reaching its theoretic capacity. Also, the battery exhibited a large reversible capacity of about 1100 mAh g at 0.5 C and 1000 mAh g at 1 C after 100 cycles. At a high rate of 2 C and 5 C, after 300 cycles, the discharge capacity finally stabilized at 805 and 585 mAh g. Even at a 94.88% sulfur content, the cathode can still deliver an extremely high specific discharge capacity of 1259 mAh g with good cycle performance.
硫在正极中的高利用率和高负荷是实现锂硫电池的关键。我们通过一种简单方便的方法合成了一种由纳米片组成的 CoN 介孔球。这种材料对多硫化物具有高亲和力、快速捕获和吸收能力，并作为硫氧化还原过程的双功能催化剂；因此，它是 S 活性材料的理想基质。在 Li-S 电池中，将这种介孔球用作硫的主体，可获得非凡的电化学性能。在复合材料中，硫的含量为 72.3wt%时，CoN@S 在 0.1 C 时的比放电容量高达 1659 mAh g，几乎达到了其理论容量。此外，该电池在 0.5 C 和 1 C 时经过 100 次循环后，具有约 1100 mAh g 的大可逆容量。在 2 C 和 5 C 的高倍率下，经过 300 次循环后，放电容量最终稳定在 805 和 585 mAh g。即使在硫含量为 94.88%的情况下，正极仍能提供高达 1259 mAh g 的比放电容量和良好的循环性能。
