Liu Hanwen, Pei Wei, Lai Wei-Hong, Yan Zichao, Yang Huiling, Lei Yaojie, Wang Yun-Xiao, Gu Qinfen, Zhou Si, Chou Shulei, Liu Hua Kun, Dou Shi Xue
Institute for Superconducting and Electronic Materials, Australian Institute of Innovative Materials, University of Wollongong, Innovation Campus, Squires Way, North Wollongong, New South Wales 2500, Australia.
Key Laboratory of Materials Modification by Laser, Ion and Electron Beams, Dalian University of Technology, Ministry of Education, Dalian 116024, China.
ACS Nano. 2020 Jun 23;14(6):7259-7268. doi: 10.1021/acsnano.0c02488. Epub 2020 May 27.
Room-temperature sodium-sulfur (RT-Na/S) batteries hold great promise for sustainable and cost-effective applications. Nevertheless, it remains a great challenge to achieve high capacity and cycling stability due to the low activity of sulfur and the sluggish conversion kinetics between polysulfide intermediates and sodium sulfide. Herein, an electrocatalyzing S cathode is fabricated, which consists of porous core-shell structure and multisulfiphilic sites. The flexible carbon structure effectively buffers volume changes during cycling and provides enclosed spaces to store S with exceptional conductivity. Significantly, the multisulfiphilic sites (ZnS and CoS) enhance catalysis toward multistep S conversion, which effectively suppresses long-chain polysulfides dissolution and improves the kinetics of short-chain polysulfides. Thus, the obtained S cathodes achieve an enhanced cycling performance (570 mAh g at 0.2 A g over 1000 cycles), decent rate capability (250 mAh g at 1.0 A g over 2000 cycles), and high energy density of 384 Wh kg toward practical applications.
室温钠硫（RT-Na/S）电池在可持续和具有成本效益的应用方面具有巨大潜力。然而，由于硫的活性较低以及多硫化物中间体与硫化钠之间缓慢的转化动力学，实现高容量和循环稳定性仍然是一个巨大的挑战。在此，制备了一种电催化硫阴极，其由多孔核壳结构和多亲硫位点组成。柔性碳结构有效地缓冲了循环过程中的体积变化，并提供了封闭空间来存储具有优异导电性的硫。值得注意的是，多亲硫位点（ZnS和CoS）增强了对多步硫转化的催化作用，有效抑制了长链多硫化物的溶解，并改善了短链多硫化物的动力学。因此，所制备的硫阴极在实际应用中实现了增强的循环性能（在0.2 A g下1000次循环中为570 mAh g）、良好的倍率性能（在1.0 A g下2000次循环中为250 mAh g）以及384 Wh kg的高能量密度。
