School of Chemical Engineering, Zhejiang University of Technology, Hangzhou 310014, China.
Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China.
Molecules. 2023 Apr 10;28(8):3335. doi: 10.3390/molecules28083335.
A sulfur doping strategy has been frequently used to improve the sodium storage specific capacity and rate capacity of hard carbon. However, some hard carbon materials have difficulty in preventing the shuttling effect of electrochemical products of sulfur molecules stored in the porous structure of hard carbon, resulting in the poor cycling stability of electrode materials. Here, a multifunctional coating is introduced to comprehensively improve the sodium storage performance of a sulfur-containing carbon-based anode. The physical barrier effect and chemical anchoring effect contributed by the abundant C-S/C-N polarized covalent bond of the N, S-codoped coating (NSC) combine to protect SGCS@NSC from the shuttling effect of soluble polysulfide intermediates. Additionally, the NSC layer can encapsulate the highly dispersed carbon spheres inside a cross-linked three-dimensional conductive network, improving the electrochemical kinetic of the SGCS@NSC electrode. Benefiting from the multifunctional coating, SGCS@NSC exhibits a high capacity of 609 mAh g at 0.1 A g and 249 mAh g at 6.4 A g. Furthermore, the capacity retention of SGCS@NSC is 17.6% higher than that of the uncoated one after 200 cycles at 0.5 A g.
硫掺杂策略经常被用于提高硬碳的储钠比容量和倍率性能。然而，一些硬碳材料难以阻止电化学产物在硬碳多孔结构中硫分子的穿梭效应，从而导致电极材料的循环稳定性较差。在此，引入了一种多功能涂层来全面提高含硫碳基阳极的储钠性能。N、S 共掺杂涂层（NSC）中丰富的 C-S/C-N 极化共价键提供的物理阻挡效应和化学锚固效应结合起来，可以保护 SGCS@NSC 免受可溶性多硫化物中间体的穿梭效应的影响。此外，NSC 层可以将高度分散的碳球包裹在交联的三维导电网络中，提高 SGCS@NSC 电极的电化学动力学性能。得益于多功能涂层，SGCS@NSC 在 0.1 A g 时表现出 609 mAh g 的高容量，在 6.4 A g 时表现出 249 mAh g 的高容量。此外，在 0.5 A g 下循环 200 次后，SGCS@NSC 的容量保持率比未涂层的提高了 17.6%。
