Abstract Designing mixed metal oxides with uniform nanostructures as a significant electrode material in energy storage devices is a vital concern for the whole world. But achieving this goal is plagued by many problems such as tedious procedures, hard morphology control and poor conductivities. The NiCo2O4/NiFe2O4 hollow nanospheres (NSs) are prepared for the first time through a novel one-pot approach. The introduced NiFe2O4 has amazingly improved the electrochemical performance of NiCo2O4 hollow NSs in both Li-ion batteries (LIBs) and supercapacitors (SCs). And the ratio of Fe to Ni plays an important role for the improvement of electrochemical performance. The NiCo2O4/NiFe2O4 hollow NSs exhibit superior capacity/capacitance values (3795 F g−1 at a current density of 1 A g−1) and fine cycling performances (11.0% specific capacitance decay after 6000 cycles) which can be attributed to the larger specific surface area of hollow NSs and the synergistic effect of two components. This provides a feasible preview of their practical applications.

中文翻译：

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均匀的 NiCo 2 O 4 /NiFe 2 O 4 空心纳米球，具有优异的锂离子电池和超级电容器性能

摘要 设计具有均匀纳米结构的混合金属氧化物作为储能设备中的重要电极材料是全世界关注的重要问题。但实现这一目标受到许多问题的困扰，例如繁琐的程序、难以控制的形态和导电性差。NiCo2O4/NiFe2O4 空心纳米球 (NSs) 是首次通过一种新型的一锅法制备。引入的 NiFe2O4 惊人地提高了 NiCo2O4 空心 NSs 在锂离子电池 (LIB) 和超级电容器 (SC) 中的电化学性能。Fe与Ni的比例对电化学性能的提高起着重要作用。NiCo2O4/NiFe2O4 中空 NSs 表现出优异的容量/电容值（在 1 A g-1 的电流密度下为 3795 F g-1）和良好的循环性能（11. 0% 的比电容在 6000 次循环后衰减），这可归因于中空 NS 的更大比表面积和两种组分的协同效应。这为他们的实际应用提供了可行的预览。