Fabrication of porous nanosheet-based Co3O4 hollow nanocubes for electrochemical capacitors with high rate capability
Fabrication of porous nanosheet-based Co3O4 hollow nanocubes for electrochemical capacitors with high rate capability
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DOI：
10.1016/j.electacta.2015.08.057
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发表时间：
2015-10
影响因子：
6.6
通讯作者：
Changhui Zhao;Baoyu Huang;Wenbin Fu;Jiayi Chen;Jinyuan Zhou;E. Xie
中科院分区：
文献类型：
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作者：
Changhui Zhao;Baoyu Huang;Wenbin Fu;Jiayi Chen;Jinyuan Zhou;E. Xie
采用Cu 2 O模板辅助法结合空气中的后煅烧工艺合成了具有均匀孔结构和高比表面积的Co 3 O 4中空纳米立方体。结果表明，所制备的空心Co 3 O 4纳米立方体壳层为多孔结构，由许多相互交错的纳米片层（厚度约为5 nm）组成。纳米片网络和中空纳米立方体内的多孔互连都可以促进电子和电解质离子的传输，从而导致高的电化学性能。正如预期的那样，这些Co 3 O 4纳米立方体表现出比电容（在0.5 A g-1的充放电电流密度下为404.9 F g-1）、优异的倍率性能（在20 A g-1下容量保持率为87.8%）和良好的循环稳定性（在2000次循环后约损失5%）。此外，以活性炭为负极的组装非对称系统在功率密度为0.4 kW kg-1时，输出能量密度可达21.8 W h kg-1，在功率密度为8 kW kg-1时，输出能量密度仍保持在51.8%左右，进一步显示了高倍率性能。
Well-defined hierarchical Co3O4hollow nanocubes with uniform porous structures and high specific surface area have been synthesized by Cu2O template-assisted method combing a post-calcination process in air. Results show that the obtained hollow Co3O4nanocubes are porous in their shells, which are built up of many interlaced ultrathin nanosheets (∼5 nm in thickness). Both nanosheet networks and porous interconnections within hollow nanocubes can facilitate the transportation of electrons and electrolyte ions, and accordingly result in high electrochemical performances. As is expected, these Co3O4nanocubes exhibit a specific capacitance (404.9 F g–1at a charge-discharge current density of 0.5 A g–1), excellent rate capability (87.8% capacity retention at 20 A g–1), and good cycling stability (about 5% lose after 2000 cycles). Moreover, the assembled asymmetric systems using activated carbon as negative electrode can output a high energy density of 21.8 W h kg–1at power density of 0.4 kW kg–1; even maintain 51.8% at a high power density of 8 kW kg–1, further showing high rate capability.