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NiCo2S4とその複合体の合成、キャラクタリゼーション及び高性能スーパーキャパシタへの応用
https://doi.org/10.18997/00006819
https://doi.org/10.18997/000068197ad3d948-d9d0-4f6b-95eb-88bddf661b57
| 名前 / ファイル | ライセンス | アクション |
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sei_k_309.pdf (10.7 MB)
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| アイテムタイプ | 学位論文 = Thesis or Dissertation(1) | |||||||||
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| 公開日 | 2018-06-13 | |||||||||
| 資源タイプ | ||||||||||
| 資源タイプ識別子 | http://purl.org/coar/resource_type/c_db06 | |||||||||
| 資源タイプ | doctoral thesis | |||||||||
| タイトル | ||||||||||
| タイトル | Synthesis and characterization of NiCo2S4 and its composites with unique nanostructure and their application for supercapacitors with high electrochemical performance | |||||||||
| 言語 | en | |||||||||
| タイトル | ||||||||||
| タイトル | NiCo2S4とその複合体の合成、キャラクタリゼーション及び高性能スーパーキャパシタへの応用 | |||||||||
| 言語 | ja | |||||||||
| 言語 | ||||||||||
| 言語 | eng | |||||||||
| 著者 |
張, 志国
× 張, 志国
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| 抄録 | ||||||||||
| 内容記述タイプ | Abstract | |||||||||
| 内容記述 | Supercapacitors (SCs) have been attracting attention due to their high power density and safety. They have been widely used in various fields. However, the low energy density limits their application. According to the equation of E=1/2 CV2, the high energy density can be achieved by enhancing specific capacitance and broadening operating voltage. Hence, great efforts have been focused on optimizing the electrode material and assembling asymmetric supercapacitors. Generally, faradaic electrode materials possess higher specific capacitance than carbon-based materials attributed to the redox reaction. The faradaic materials include conducting polymers and transition metal oxides/sulfides. However, the conducting polymers inevitably swell and shrink during the redox reaction process, it can lead to poor stability and limited capacitance. Therefore, the transition metal oxide is a promising candidate. However, the intrinsically slow kinetic and poor electrical conductivity of transition metal oxides result into low rate-capability, which restrict their practical application. In order to achieve a high capacitance and desirable rate performance, development of the electrode materials with high conductivity is required. On the other hand, transition metal sulfides have good conductivity. Among many kinds of transition metal sulfides, NiCo2S4 is a great potential candidate due to its metallic conductivity, controllable morphology and high capacitance. Therefore, this thesis mainly focuses on the NiCo2S4 and NiCo2S4-based composites for high-performance SCs. The NiCo2S4 and its composite are synthesized by a simple method and controlled their nanostructure from 1D to 3D. The asymmetric flexible and solid-state supercapacitors are also assembled. The results of electrochemical measurements indicated that NiCo2S4@VS2 and NiCo2S4@MnS composites are great potential for energy storage systems. In chapter 1, the structure and fundamental of SCs is briefly described. The energy storage mechanism of SCs is also given in detail. The previous studies of electrode materials are introduced. In the end of this chapter, the research purpose is presented. In chapter 2, the reagents and apparatus used in this work are summarized. The physical and chemical characterizations are carried out, including X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The electrochemical measurements based on cyclic voltammograms (CV) and galvanostatic charge-discharge (GCD) are also explained. In chapter 3, several materials of NiCo2S4 with different morphologies are synthesized. The growth mechanism is deduced. Compared to the needle (1D) and flake (2D) structures, the 3D honeycomb NiCo2S4 shows an excellent electrochemical performance. The maximum specific capacitance is up to 7.4 F cm-2 at a current density of 1 mA cm-2. The specific capacitance remains 99% of the initial capacitance at a current density of 10 mA cm-2, indicating that 3D honeycomb NiCo2S4 has good stability. In chapter 4, the NiCo2S4@VS2 with unique structure on Ni foam is prepared by a simple in-situ hydrothermal method and one-step sulfurization. Highly conductive NiCo2S4 nanoneedle arrays are in situ grown on 3D sponge-like Ni foam, which expose accessible sites for growing ultrathin VS2 nanosheets, resulting into desirable rate capability and remarkable cycle performance. The prepared NiCo2S4@VS2 displays a high specific capacitance of 1968 F g-1 due to the synergetic effects. In addition, aqueous asymmetric SCs are assembled based on NiCo2S4@VS2 and active carbon. The operating potential of devices is enlarged to 1.55 V. A maximum energy density of 31.2 Wh kg-1 is achieved at the power density of 775 W kg-1. The device also shows high-rate capability under different current densities. In chapter 5, the NiCo2S4@MnS composite is prepared and their properties are studied. The carbon cloth is used as substrate owing to the good conductivity and mechanical strength. Additionally, an solid-state flexible asymmetric SC is fabricated using NiCo2S4@MnS/carbon cloth as positive electrode, active carbon/carbon cloth as negative electrode and poly(vinyl alcohol)/KOH gel as electrolytes, respectively. The device shows an energy density of 23.3 Wh kg-1 at a power density 725 W kg-1 and a maximum power density was 7.25 kW kg-1 at an energy density of 5.11 Wh kg-1 in a potential range of 0-1.45 V. The solid-state asymmetric supercapacitor has excellent mechanical flexibility. These results suggest that the NiCo2S4@MnS composite hold a great potential for energy storage applications. Finally, general conclusions and future prospects are described. The investigations of NiCo2S4 and NiCo2S4 based composites are carried out from two aspects of synthesis method and electrochemical performance. The further studies need to focus on exploring the new materials and fabricating new structure device with high-performance. | |||||||||
| 目次 | ||||||||||
| 内容記述タイプ | TableOfContents | |||||||||
| 内容記述 | 1 Introduction||2 Experimental section||3 The growth mechanism of NiCo2S4 and the electrochemical performance in supercapacitors||4 NiCo2S4@VS2 with core-shell structure for high-performance asymmetric supercapacitors||5 Solid-state flexible asymmetric supercapacitors with high energy and power densities based on NiCo2S4@MnS and AC | |||||||||
| 備考 | ||||||||||
| 内容記述タイプ | Other | |||||||||
| 内容記述 | 九州工業大学博士学位論文 学位記番号：生工博甲第309号 学位授与年月日：平成30年3月23日 | |||||||||
| キーワード | ||||||||||
| 主題Scheme | Other | |||||||||
| 主題 | NiCo2S4 | |||||||||
| キーワード | ||||||||||
| 主題Scheme | Other | |||||||||
| 主題 | composite | |||||||||
| キーワード | ||||||||||
| 主題Scheme | Other | |||||||||
| 主題 | nanostructure | |||||||||
| キーワード | ||||||||||
| 主題Scheme | Other | |||||||||
| 主題 | energy density | |||||||||
| キーワード | ||||||||||
| 主題Scheme | Other | |||||||||
| 主題 | supercapacitor | |||||||||
| アドバイザー | ||||||||||
| 馬, 廷麗 | ||||||||||
| 学位授与番号 | ||||||||||
| 学位授与番号 | 甲第309号 | |||||||||
| 学位名 | ||||||||||
| 学位名 | 博士（工学） | |||||||||
| 学位授与年月日 | ||||||||||
| 学位授与年月日 | 2018-03-23 | |||||||||
| 学位授与機関 | ||||||||||
| 学位授与機関識別子Scheme | kakenhi | |||||||||
| 学位授与機関識別子 | 17104 | |||||||||
| 学位授与機関名 | 九州工業大学 | |||||||||
| 学位授与年度 | ||||||||||
| 内容記述タイプ | Other | |||||||||
| 内容記述 | 平成29年度 | |||||||||
| 出版タイプ | ||||||||||
| 出版タイプ | VoR | |||||||||
| 出版タイプResource | http://purl.org/coar/version/c_970fb48d4fbd8a85 | |||||||||
| アクセス権 | ||||||||||
| アクセス権 | open access | |||||||||
| アクセス権URI | http://purl.org/coar/access_right/c_abf2 | |||||||||
| ID登録 | ||||||||||
| ID登録 | 10.18997/00006819 | |||||||||
| ID登録タイプ | JaLC | |||||||||
