Constructing electrode materials with high energy densities are the effective way to develop asymmetric supercapacitor devices. Therefore, the inlay of conductive materials into pseudo‐capacitive constituents is a practical approach to increase the performance of supercapacitors electrodes. Herein, we declare a facile one‐step as an economic strategy for tailoring of carbon spheres (CSs) impregnated by CoFe2O4 to form CoFe2O4@CSs composite. The composite CoFe2O4@CSs was fully characterized by X‐ray diffraction (XRD), Raman spectroscopy, X‐ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM), which evinced that CoFe2O4 nanoparticles were densely and cored inside carbons spheres. Moreover, the electrochemical characterization of CoFe2O4@CSs composite was manifested high specific capacitance of (600 F/g) at a current density (1 A/g), high‐performance rate, and cycling stability. CoFe2O4@CSs has achieved capacitance retentions of 94.1% after 5000 charge/discharge cycles at a current density of 20 mA/g. The device based asymmetric supercapacitors was found to improve the energy density with 27.08 Wh/kg at a power density of 750 W/kg with 99 % capacitance retention which was higher than the previously reported. The exceptional performance of CoFe2O4@CSs composites gives high priority for such materials in variant electrochemical fields due to the wonderful harmony impacts between CoFe2O4 nanoparticles and carbon spheres.

中文翻译：

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一种简单的一步溶剂热法制备的新型复合CoFe2O4 @ CSs电极，可提高混合超级电容器的电化学性能

构造具有高能量密度的电极材料是开发不对称超级电容器器件的有效方法。因此，将导电材料嵌入伪电容成分中是提高超级电容器电极性能的实用方法。在这里，我们宣布一个简单的步骤，就是一种经济的策略，用于定制被CoFe2O4浸渍的碳球（CSs）以形成CoFe2O4 @ CSs复合材料。通过X射线衍射（XRD），拉曼光谱，X射线光电子能谱（XPS）和透射电子显微镜（TEM）对复合CoFe2O4 @ CSs进行了全面表征，这表明CoFe2O4纳米颗粒密集且内在碳球内部。此外，CoFe2O4 @ CSs复合材料的电化学特性表现为在电流密度（1 A / g）下具有高比电容（600 F / g），高性能和循环稳定性。CoFe2O4 @ CSs在20 mA / g的电流密度下经过5000次充电/放电循环后，电容保持率达到94.1％。发现基于器件的非对称超级电容器在功率密度为750 W / kg时具有27.08 Wh / kg的能量密度，并且具有99％的电容保持率，高于先前报道的水平。由于CoFe2O4纳米粒子与碳球之间的奇妙的和谐影响，CoFe2O4 @ CSs复合材料的卓越性能使其在各种电化学领域中具有较高的优先级。5000次充/放电循环后，电流密度为20 mA / g时为1％。发现基于器件的非对称超级电容器在功率密度为750 W / kg时具有27.08 Wh / kg的能量密度，并且具有99％的电容保持率，高于先前报道的水平。由于CoFe2O4纳米粒子与碳球之间的奇妙的和谐影响，CoFe2O4 @ CSs复合材料的卓越性能使其在不同的电化学领域中具有较高的优先级。5000次充/放电循环后，电流密度为20 mA / g时为1％。发现基于器件的非对称超级电容器在功率密度为750 W / kg时具有27.08 Wh / kg的能量密度，并且具有99％的电容保持率，高于先前报道的水平。由于CoFe2O4纳米粒子与碳球之间的奇妙的和谐影响，CoFe2O4 @ CSs复合材料的卓越性能使其在各种电化学领域中具有较高的优先级。