A high-performance lithium-ion capacitor with carbonized NiCo2O4 anode and vertically-aligned carbon nanoflakes cathode
A high-performance lithium-ion capacitor with carbonized NiCo2O4 anode and vertically-aligned carbon nanoflakes cathode
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DOI：
10.1016/j.ensm.2019.07.034
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发表时间：
2019-11-01
影响因子：
20.4
通讯作者：
Zhu, Yu
中科院分区：
文献类型：
--
作者：
Cheng, Chung-Fu;Li, Xiang;Zhu, Yu
锂离子电容器(LIC)是一种集超级电容器和锂离子电池的互补功能于一体的储能装置，可同时达到高能量和高功率密度。LIC技术的主要挑战之一是法拉第插入阳极和电容阴极之间的动力学不平衡。因此，电极材料的设计对于提高LIC器件中阳极的倍率性能和阴极的电容至关重要。在本工作中，我们展示了具有纳米结构的阴极和阳极的新型LIC。垂直排列的碳纳米片(VACNF)阴极具有高的电化学活性表面积和良好的导电性，而金属有机骨架(MOF)碳化镍钴氧化物(cNico(2)O(4))负极保证了快速的转化反应和显著的循环性能。单个电极的电化学表征证实了两种电极都具有良好的电子和离子传输能力。利用优化的电极活性材料负载制造了LIC，以在所需的充放电速率下提供高能量密度。器件的能量密度可达136.9Wh/kg(200W/kg)。在40kW/kg的较高功率密度下，在4 S内完成一次充分充放电的情况下，LIC仍可提供26.44Wh/kg的能量密度。在1-4.2V的电压范围内，器件还表现出良好的循环稳定性(9000次循环后，在4A/g的电流密度下，电容保持率接近90%)。
Lithium ion capacitors (LICs) are energy storage devices integrating the complementary features of both supercapacitors and lithium ion batteries to simultaneously reach high energy and power densities. One of the major challenges in LIC technology is the kinetic imbalance between the faradaic insertion anode and capacitive cathode. Therefore, the design of electrode materials is crucial to enhance the rate performance of anode and the capacitance of the cathode in LIC devices. In this work, novel LICs were demonstrated with nanostructured cathode and anode. A vertically-aligned carbon nanoflakes (VACNFs) cathode provided high electrochemically active surface area and excellent conductivity, while a metal organic framework (MOF) derived carbonized nickel cobalt oxide (cNiCo(2)O(4)) anode ensured fast conversion reactions and remarkable cyclability. Electrochemical characterization of individual electrode confirmed that both electrodes exhibited good electron and ion transport capability. The LICs were fabricated with optimized electrode active materials loading to deliver high energy densities at desired charge/discharge rates. The devices exhibited energy density up to 136.9W h/kg (at 200 W/ kg). At higher power density of 40 kW/kg, under which a full charge-discharge can be finished within 4 s, the LICs could still deliver an energy density of 26.44W h/kg. The devices also showed a good cycle stability (approximate to 90% capacitance retention after 9000 cycles, under current density of 4 A/g) within the voltage range of 1-4.2 V.