【作者】 张雷；

【导师】 王荣方；

【作者基本信息】 青岛科技大学 ， 化学工程与技术， 2020， 硕士

【摘要】 近几年来,超级电容器以其充放电速度快、使用寿命长、能量密度输出高等诸多优点而深受人们的青睐。作为超级电容器的“心脏”的电极材料,对超级电容器的性能的好坏起着决定性的作用。随着对过渡金属电极研究的深入,特别是镍钴基材料的开发和使用,极大地推动了超级电容器电极的发展和进步。随着微电子时代的来临,各种电子设备朝向更小,更便于携带的方向发展,这也对超级电容器电极的发展提出了新的要求。以此为契机,本论文通过在柔性基底上,采用简单可行的方法,制备了一系列的镍钴基柔性电容器电极活性物质并进行了性能研究。论文的工作分为三个部分:（1）采用电沉积的方式,将Ni（OH）₂修饰的Ni₃S₂纳米簇负载于导电布镍层之上成功制备了可弯折的Ni（OH）₂/Ni₃S₂复合电极。通过多种物理结构表征来确定材料的组成成分、表面价态及纳米结构,并进行了电化学测试,评估其在具体电化学器件中的实际工作能力。所制备的分层花椰菜状纳米结构具有较大比表面积和较高导电性,表现出优异的电化学性能。在充放电电流密度为3 mA cm^-2时,Ni（OH）₂/Ni₃S₂复合电极材料的比电容高达1800 F g^-1;当电流密度提高到15 mA cm^-2时,电极材料仍有72%的容量保持率。另外,在充放电循环7000圈后,电极的比电容仅下降15%,证明其具有良好的稳定性。为了进一步考察其在实际应用中的表现,组装了Ni（OH）₂/Ni₃S₂//AC不对称电容器并对其进行相关电化学测试。测试结果表明该器件能够在3.54 mW cm^-2的功率密度下,所制得的电容器可以提供0.49 mWh cm^-2的能量密度。（2）为了提高基底材料的稳定性,用耐腐蚀且电化学性质更为稳定的碳布作为支撑结构,采用水热的方式,成功制备了次生纳米片修饰的NiS纳米片阵列。通过多种结构表征手段来确定材料的组成成分、表面价态及微观结构,并制作电极进行电化学测试来评估其在具体电化学器件中的表现。所制得的NiS纳米片阵列具有高的比表面积,为离子传输和电子传递提供了更为有利的条件,表现出优异的电化学性能。在充放电电流密度为2 mA cm^-2时,NiS/CC复合电极材料表现出430μAh cm^-2的高比电容。在经过5000圈充放电循环后,电极的比电容仅仅下降了15%,表现出良好的循环稳定性。组装了NiS/CC//AC不对称电容器并进行了相关的电化学测试。在1.6 V电压窗口下,当功率密度为54.86 W kg^-1时,可以提供10.97 Wh kg^-1的能量密度。（3）为了进一步提高NiS/CC电极的电化学性能,采用电沉积修饰的方法,在NiS纳米片阵列表面包覆Co（OH）₂纳米片制备了核壳结构的Co（OH）₂/NiS/CC复合材料。通过多种结构表征手段来确定材料的组成成分、表面价态及结构。前体NiS的开放结构为进一步的电沉积生长Co（OH）₂提供了丰富的生长位点,所制得复合的比容量和电化学稳定性都得到了极大地提高。在2 mA cm^-2充放电电流密度下,Co（OH）₂/NiS/CC复合电极材料的比电容高达668μAh cm^-2,当电流密度提高到30 mA cm^-2时,电极材料仍能有62%的电容保持率。在经过10000充放电循环圈后,电容保持率仅仅下降了3%。为了进一步考察其实际应用的表现,组装了Co（OH）₂/NiS/CC//AC不对称电容器并进行了相关的电化学测试。当功率密度达到4.72 mW cm^-1时,所制得的不对称电容器的能量密度可以达到0.58 mWh cm^-2。更多还原

【Abstract】 Supercapacitors,due to their many advantages such as fast charge and discharge speed,long service life,aroused more ttention.Electrode materials,as the"heart"of supercapacitors,play a vital role in evaluating the performance of supercapacitors.With the in-depth study of transition metal electrodes,especially the development and use of nickel-cobalt-based materials,the development and popularization of supercapacitors has been greatly promoted.With the advent of the microelectronics era,various electronic devices are becoming smaller and more portable,which has also put forward new requirements for the development of supercapacitors electrode.（1）A flexible cathode with highly electrochemical performance for bendable supercapacitors have been achieved by electrochemical depositing hierarchical nanostructured Ni₃S₂/Ni（OH）₂ compounds on the surface of commercial conductive textile.A variety of physical structure characterizations are used to determine the material composition,surface valence,and nanostructures,and electrodes are made for electrochemical testing to evaluate their performance in electrochemical devices.Due to profuse exposed-edge planes,the obtained electrode exhibits remarkable hybrid properties with a highly specific capacity of 361μAh cm^-2 at 2 mA cm^-2 in 3 M KOH medium,and excellent cycling stability（85%capacitance retention after 5000 cycles）.Further,the fabricated flexible and lightweight electrode is used to evaluate its performance in a solid-state flexible hybrid battery.The assembled flexible hybrid battery exhibits a high energy density of 10.97 Wh kg^-1 with a power density of 54.86mWh kg^-1.（2）In order to improve the stability of the substrate material,.nickel sulfide sheet-like nanoarray（NiS）with secondary nanoflakes vertically grown on primary nanosheets is fabricated via sulfurization of hierarchical structured Ni（OH）₂ supported on carbon cloth substrate.A carbon cloth with more corrosion resistance and more stable electrochemical properties is used as a support structure,and a secondary nanosheet modified NiS nanosheet array is grown by a hydrothermal method.A variety of physical structure characterizations are used to determine the material composition,surface valence,and nanostructures,and electrodes are made for electrochemical testing to evaluate their performance in specific electrochemical devices.Because of its unique open nanostructure,the prepared NiS nanosheet array has a high specific surface area,which undoubtedly provides more favorable conditions for ion transmission and electron transfer,and therefore exhibits excellent electrochemical performance.When the charge and discharge current density at 2 mA cm^-2,the NiS/CC composite electrode material shows a high specific capacitance of 430μAh cm^-2.When the current density is increased to 20 mA cm^-2,the electrode material can still reach 45%.The capacity retention and AC impedance tests show that the NiS/CC electrode has a smaller and smaller series resistance（0.743Ω）.（3）Hierarchical arrays of transition metal compounds directly grown on a current collector to fabricate the binder-free electrode are a promising strategy to achieve high-performance hybrid supercapacitors owing to its high surface area and low inner resistance.To engineer the microstructure of the hierarchical structure can further efficiently improve capacitive performance.In this work,a hierarchically structured Ni（OH）₂/NiS nano-sheet arrays,with the vertical growth of secondary nanosheets on their surface,are directly fabricated onto carbon cloth via an NH₄F-induced method.Besides,the Ni（OH）₂/NiS electrode also delivers excellent performance in a solid-state flexible supercapacitor.When the power density reach 4.72 W cm^-2,the obtained capacitor can provide an energy density of 0.58 mWh cm^-2.更多还原