Exploring high-performance and low-priced electrode materials for supercapacitors is important but remains challenging. In this work, a unique sandwich-like nanocomposite of reduced graphene oxide (rGO)-supported N-doped carbon embedded with ultrasmall CoNiS_x nanocrystallites (rGO/CoNiS_x/N–C nanocomposite) has been successfully designed and synthesized by a simple one-step carbonization/sulfurization treatment of the rGO/Co–Ni precursor. The intriguing structural/compositional/morphological advantages endow the as-synthesized rGO/CoNiS_x/N–C nanocomposite with excellent electrochemical performance as an advanced electrode material for supercapacitors. Compared with the other two rGO/CoNiO_x and rGO/CoNiS_x nanocomposites, the rGO/CoNiS_x/N–C nanocomposite exhibits much enhanced performance, including a high specific capacitance (1028.2 F g⁻¹ at 1 A g⁻¹), excellent rate capability (89.3% capacitance retention at 10 A g⁻¹) and good cycling stability (93.6% capacitance retention over 2000 cycles). In addition, an asymmetric supercapacitor (ASC) device based on the rGO/CoNiS_x/N–C nanocomposite as the cathode and activated carbon (AC) as the anode is also fabricated, which can deliver a high energy density of 32.9 W h kg⁻¹ at a power density of 229.2 W kg⁻¹ with desirable cycling stability. These electrochemical results evidently indicate the great potential of the sandwich-like rGO/CoNiS_x/N–C nanocomposite for applications in high-performance supercapacitors.

中文翻译：

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嵌入在还原石墨烯氧化物上锚固的氮掺杂碳中的 双金属CoNiS _x纳米微晶，用于高性能超级电容器†

探索用于超级电容器的高性能和低价电极材料固然重要，但仍具有挑战性。在这项工作中，通过一种简单的方法成功地设计和合成了一种独特的三明治状纳米复合材料，该复合材料由氧化石墨烯（rGO）负载的N掺杂碳掺杂，并嵌入了超小型CoNiS _x纳米微晶（rGO / CoNiS _x / NC –C纳米复合材料）。 rGO / Co-Ni前体的分步碳化/硫化处理。引人入胜的结构/成分/形态优势赋予了合成的rGO / CoNiS _x / NC纳米复合材料优异的电化学性能，可作为超级电容器的先进电极材料。与其他两个rGO / CoNiO _x和rGO / CoNiS _x相比纳米复合材料，所述RGO /中山市哥尼斯_X / N-C纳米复合材料表现出很大增强的性能，包括高的比电容（1028.2 F G ^-1 1 A G ^-1），优良的速率能力（89.3％容量保持在10 A G ^-1）和良好的循环稳定性（2000周期内93.6％的电容保持率）。此外，还制造了基于rGO / CoNiS _x / N–C纳米复合材料作为阴极和活性炭（AC）作为阳极的不对称超级电容器（ASC）装置，该装置可提供32.9 W h kg的高能量密度^-1在229.2 W kg ^-1的功率密度下具有理想的循环稳定性。这些电化学结果显然表明，夹心型rGO / CoNiS _x / N–C纳米复合材料在高性能超级电容器中具有巨大的潜力。