The rational design and synthesis of advanced electrode materials are significant for the applications of supercapacitors. Ferroferric oxide (Fe₃O₄), with its high theoretical capacitance is a renowned cathode material. Nevertheless, its low electronic conductivity and poor cycling stability during a long-term charge/discharge process limit its large-scale applications. In this work, the precise modulation of multiple components was reported to enhance electrochemical performance. The ternary heterostructures were fabricated by wrapping ultrathin nickel hydroxide (Ni(OH)₂) nanosheets on the surfaces of Fe₃O₄ nanoparticles-loaded on sodium carboxymethyl cellulose (CMC)-derived porous carbon, named as C/Fe₃O₄@Ni(OH)₂. Due to the large specific surface area and excellent conductivity of CMC-derived porous carbon and the abundant reaction sites of Ni(OH)₂ nanosheets, the optimized C/Fe₃O₄@Ni(OH)₂–1.0 sample exhibited the highest specific capacitance of 3072F g⁻¹ at a current density of 0.5 A g⁻¹. Furthermore, the assembled asymmetric supercapacitor (ASC) with activated carbon and C/Fe₃O₄@Ni(OH)₂–1.0 as the negative and positive electrodes, respectively, showed an energy density of 123 W h kg⁻¹ at 381 W kg⁻¹, and a long-life stability with an excellent capacitance retention of 90.04 % after 10,000 cycles. The route for preparing composite electrode materials proposed in this work provides a reference for realizing high-performance energy storage devices.

合理设计和合成先进的电极材料对于超级电容器的应用具有重要意义。具有高理论电容的四氧化三铁 (Fe ₃ O ₄ ) 是著名的阴极材料。然而，其低电子电导率和长期充放电过程中较差的循环稳定性限制了其大规模应用。在这项工作中，据报道多个组件的精确调制可以提高电化学性能。三元异质结构是通过将超薄氢氧化镍 (Ni(OH) ₂ ) 纳米片包裹在载有羧甲基纤维素钠 (CMC) 衍生多孔碳的 Fe ₃ O ₄纳米粒子表面制成的，命名为 C/Fe₃ O ₄ @Ni(OH) ₂。由于 CMC 衍生的多孔碳具有较大的比表面积和优异的导电性以及 Ni(OH) ₂纳米片的丰富反应位点，优化后的 C/Fe ₃ O ₄ @Ni(OH) ₂ –1.0 样品表现出最高的比表面积在 0.5 A g ^-1的电流密度下，电容为 3072F g ^-1。此外，分别以活性炭和 C/Fe ₃ O ₄ @Ni(OH) ₂ –1.0 作为负极和正极的组装不对称超级电容器 (ASC)在 381 W时显示出 123 W h kg ^-1的能量密度公斤^-1，以及长寿命稳定性，在 10,000 次循环后具有 90.04% 的出色电容保持率。该工作提出的复合电极材料制备途径为实现高性能储能器件提供了参考。