Ti₃C₂ MXenes have revealed immense potential in energy storage systems. Herein, we report the development of a flexible solid-state asymmetric supercapacitor (ASC) device by assembling spherical NiCo₂S₄ as a cathode, a MXene-reduced graphene oxide sponge (rGO_sp) nanocomposite as an anode, and polyvinyl alcohol (PVA) hydrogel comprising a mixture of 3 M KOH and 0.1 M K₄[Fe(CN)₆] as an electrolyte cum separating membrane. This device (NiCo₂S₄//MXene-rGO_sp) provides a specific capacitance (C_S) of 98 F g⁻¹ (at 4.5 A g⁻¹), coulombic efficiency of ∼99% at 15 A g⁻¹, and C_S of ∼95% after 4000 cycles. Moreover, it provides an energy density of 35.75 W h kg⁻¹ at a power density of 3693 W kg⁻¹. This device establishes its mechanical flexibility by exhibiting almost similar performances at various deformed structures. The performance of this flexible NiCo₂S₄//MXene-rGO_sp ASC device is superior to many reported MXene-based supercapacitors. This device is also capable of illuminating a series of LED lights. In conclusion, the results clearly prove the potential of this device in high-performance energy storage applications.

中文翻译：

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以NiCo2S4为阴极、MXene还原氧化石墨烯海绵为阳极的高性能柔性固态非对称超级电容器

Ti ₃ C ₂ MXenes 在储能系统中展现出巨大的潜力。在此，我们报告了通过组装球形 NiCo ₂ S ₄作为阴极、MXene 还原氧化石墨烯海绵 (rGO _sp ) 纳米复合材料作为阳极和聚乙烯醇 (PVA) 组装而成的柔性固态不对称超级电容器 (ASC) 装置。)水凝胶，包含3M KOH和0.1MK ₄ [Fe(CN) ₆ ]的混合物作为电解质兼隔膜。该器件 (NiCo ₂ S ₄ //MXene-rGO _sp ) 提供的比电容 ( C _S ) 为 98 F g ⁻¹ (在 4.5 A g ⁻¹ )，库伦效率在 15 A g ⁻¹时为 ∼99% ，4000 次循环后C S约为 95 _{% 。此外，它在3693 W kg} ^-1的功率密度下提供35.75 W h kg ^-1的能量密度。该装置通过在各种变形结构中表现出几乎相似的性能来建立其机械灵活性。这种灵活的 NiCo ₂ S ₄ //MXene-rGO _sp ASC 器件的性能优于许多报道的基于 MXene 的超级电容器。该设备还能够照亮一系列 LED 灯。总之，结果清楚地证明了该设备在高性能储能应用中的潜力。