Zhou Yuxiang, Zhang Jianwei, Zhao Chenyuan, Shi Tianyu, Yin Haihong, Song Changqing, Qin Lin, Wang Zhiliang, Shao Haibao, Yu Ke
School of Information Science and Technology, Nantong University, Nantong 226019, China.
Key Laboratory of Polar Materials and Devices, Department of Optoelectronics, East China Normal University, Shanghai 200241, China.
Dalton Trans. 2022 Sep 26;51(37):14097-14106. doi: 10.1039/d2dt01774a.
Although lithium-sulfur batteries (LSBs) are very promising in energy storage devices, their low conductivity, shuttle effect, and volume expansion unfavorably lead to sluggish kinetics and worsening electrochemical performance. To address these problems, we firstly prepared conductive carbon nanowires embedded with lithiophilic CoSe nanoparticles (CoSe-CNWs), and utilized CoSe-CNWs to construct reduced graphene oxide (rGO) sheets; thereby, sandwich-type CoSe-CNWs@rGO composites were assembled. CoSe-CNWs@rGO composites were taken as the sulfur host. Due to the alternating rGO sheets and active sulfur, the special sandwich structure can maximize the use of sulfur, confine polysulfides physically, favor electron transport, and cushion the volume change during cycling. The interlayer CoSe-CNWs network also can entrap polysulfides chemically, promote the electron transfer, and improve the reaction kinetics, owing to the synergetic merits of high polarity and conductivity. Compared with CoSe-CNWs/S and Co-CNWs/S, the CoSe-CNWs@rGO/S cathode shows a significant improvement in cell performance. Its specific capacity decreases from 1137.9 mA h g at 0.1 C to 649.7 mA h g at 2 C, demonstrating the optimal rate performance. The cycling capacity also slowly reduces from 975.4 mA h g to 839.7 mA h g after 150 cycles at 0.5 C, showing a high retention of 86.1% with a tiny average fading rate (0.093%).
尽管锂硫电池（LSB）在储能设备中非常有前景，但其低导电性、穿梭效应和体积膨胀不利地导致动力学迟缓以及电化学性能恶化。为了解决这些问题，我们首先制备了嵌入亲锂CoSe纳米颗粒的导电碳纳米线（CoSe-CNWs），并利用CoSe-CNWs构建还原氧化石墨烯（rGO）片；从而组装了三明治型CoSe-CNWs@rGO复合材料。CoSe-CNWs@rGO复合材料被用作硫宿主。由于交替的rGO片和活性硫，这种特殊的三明治结构可以最大限度地利用硫，物理限制多硫化物，有利于电子传输，并缓冲循环过程中的体积变化。层间CoSe-CNWs网络由于具有高极性和导电性的协同优点，还可以化学捕获多硫化物，促进电子转移，并改善反应动力学。与CoSe-CNWs/S和Co-CNWs/S相比，CoSe-CNWs@rGO/S阴极在电池性能方面有显著改善。其比容量从0.1C时的1137.9 mA h g降至2C时的649.7 mA h g，展示了最佳的倍率性能。在0.5C下循环150次后，循环容量也从975.4 mA h g缓慢降至839.7 mA h g，显示出86.1%的高保留率和微小的平均衰减率（0.093%）。
