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<p>Against the backdrop of the global energy crisis and escalating environmental issues, supercapacitors have emerged as a research hotspot in the field of energy storage due to their advantages as novel high-efficiency energy storage devices, including fast charge-discharge capabilities and long cycle life. However, the performance of electrode materials remains a critical bottleneck limiting their energy density and power density. As a pseudocapacitive electrode material, NiCo<sub>2</sub>O<sub>4</sub> offers high theoretical specific capacity and redox activity, but its pure phase suffers from drawbacks such as poor electrical conductivity and limited active sites. Moreover, the modification effect of single rare earth doping is subject to a threshold. This study innovatively adopts a Sm-Ce dual rare earth synergistic doping strategy, combined with a hydrothermal-calcination process, to prepare undoped, single-doped, and dual-doped NiCo<sub>2</sub>O<sub>4</sub> materials. These are paired with CNTs/SnO<sub>2</sub> negative electrodes to assemble asymmetric supercapacitors, aiming to investigate the synergistic modification mechanism of dual rare earth elements. The results indicate that Sm and Ce co-doping creates a synergistic effect, which increases the specific surface area through lattice regulation, introduces oxygen vacancies and active sites, and optimizes the electronic structure to enhance electrical conductivity. The material exhibits a uniform porous flower-like structure with homogeneous elemental distribution. The dual-doped sample achieves a specific capacitance of 1710&#xa0;F/g, significantly higher than that of single-doped (Ce-NiCo<sub>2</sub>O<sub>4</sub>: 1539&#xa0;F/g, Sm-NiCo<sub>2</sub>O<sub>4</sub>: 1417&#xa0;F/g) and undoped samples (1267&#xa0;F/g). The assembled asymmetric device, operating within a voltage window of 1.6&#xa0;V, delivers an energy density of 95 Wh/kg at a power density of 2000&#xa0;W/kg and retains 60 Wh/kg even at a power density of 20,000&#xa0;W/kg. After 10,000 charge-discharge cycles, the capacitance retention rate is 94%, demonstrating a combination of high energy density, high power density, and excellent cycling stability. This study provides a new pathway for the design of high-performance electrode materials for supercapacitors and offers experimental evidence for the application of dual rare earth doping in transition metal oxides.</p>

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Preparation of double rare earth co-doped NiCo2O4 Nanomaterials with Their Superior Electrochemical Performance in supercapacitors

  • 期刊论文

  • 发表日期：

    2026年4月22日

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  • Zichang Wang,
  • An Li,
  • Mingzhao Xing,
  • Jing Wang,
  • Tingting Hao,
  • Jian Hao

摘要

Against the backdrop of the global energy crisis and escalating environmental issues, supercapacitors have emerged as a research hotspot in the field of energy storage due to their advantages as novel high-efficiency energy storage devices, including fast charge-discharge capabilities and long cycle life. However, the performance of electrode materials remains a critical bottleneck limiting their energy density and power density. As a pseudocapacitive electrode material, NiCo2O4 offers high theoretical specific capacity and redox activity, but its pure phase suffers from drawbacks such as poor electrical conductivity and limited active sites. Moreover, the modification effect of single rare earth doping is subject to a threshold. This study innovatively adopts a Sm-Ce dual rare earth synergistic doping strategy, combined with a hydrothermal-calcination process, to prepare undoped, single-doped, and dual-doped NiCo2O4 materials. These are paired with CNTs/SnO2 negative electrodes to assemble asymmetric supercapacitors, aiming to investigate the synergistic modification mechanism of dual rare earth elements. The results indicate that Sm and Ce co-doping creates a synergistic effect, which increases the specific surface area through lattice regulation, introduces oxygen vacancies and active sites, and optimizes the electronic structure to enhance electrical conductivity. The material exhibits a uniform porous flower-like structure with homogeneous elemental distribution. The dual-doped sample achieves a specific capacitance of 1710 F/g, significantly higher than that of single-doped (Ce-NiCo2O4: 1539 F/g, Sm-NiCo2O4: 1417 F/g) and undoped samples (1267 F/g). The assembled asymmetric device, operating within a voltage window of 1.6 V, delivers an energy density of 95 Wh/kg at a power density of 2000 W/kg and retains 60 Wh/kg even at a power density of 20,000 W/kg. After 10,000 charge-discharge cycles, the capacitance retention rate is 94%, demonstrating a combination of high energy density, high power density, and excellent cycling stability. This study provides a new pathway for the design of high-performance electrode materials for supercapacitors and offers experimental evidence for the application of dual rare earth doping in transition metal oxides.