鋰硫電池被認(rèn)為是目前最有前景的新一代鋰離子電池體系,有著極高的能量密度(2600 Wh kg-1),極高的理論容量(1675 mAh g-1)和較低的成本。但是,鋰硫電池的應(yīng)用仍存在一些問題,比如硫和電池放電產(chǎn)品硫化鈉的絕緣性,電化學(xué)反應(yīng)中間產(chǎn)物聚硫物質(zhì)溶于電解液而造成的“穿梭效應(yīng)”,還有硫化鋰的體積膨脹等。所以,增強(qiáng)硫電極的導(dǎo)電性、提高電極材料對于體積膨脹的耐受性和抑制聚硫的擴(kuò)散使其能被束縛在正極區(qū)域是發(fā)展鋰硫電池的關(guān)鍵點。本文以NaCl-KCl和納米碳酸鈣作為雙模版,通過熱解葡萄糖—脲醛樹脂—MOF MIL-53材料,制備得到了 μ-Al2O3修飾的定向介孔碳。葡萄糖—脲醛樹脂與NaCl-KCl填充在MIL-53的孔道中可以避免碳化時候孔道的坍塌和黏連。納米碳酸鈣在MIL-53孔道外面,可以避免在碳化過程中形成密封孔。制備所得的定向介孔碳具有極高的比表面積和豐富的表面氧氮位點,對于聚硫有著極強(qiáng)的吸附力。硫電極展現(xiàn)了極高的放電容量、較長的壽命和極佳的倍率性能,在0.05 ℃下初始容量高達(dá)1626 mAh 以及10 ℃情況下有著430 mAh g-1的比容量。在0.2 ℃情況下,電池循...

【文章頁數(shù)】：137 頁

【學(xué)位級別】：博士

【文章目錄】：
ACKNOWLEDGEMENTS
摘要
ABSTRACT
CHAPTER 1: BACKGROUND AND LITERATURE REVIEW
    1.1 INTRODUCTION
    1.2 PRINCIPLES OF LI-ION BATTERIES
    1.3 PRINCIPLES OF LITHIUM-SULFUR BATTERIES
    1.4 CONFIGURA LION LITHIUM-SULFUR AND LITHIUM-ION BATTERIES
    1.5 CHALLENGES OF LI-S BATTERIES
        1.5.1 Insulating active materials
        1.5.2 Dissolution of polysulfides and the related shuttle effect
        1.5.3 Corrosion of Lithium metal
        1.5.4 Non soluble lithium sulfide and sulfur plating
        1.5.5 Self-discharge
        1.5.6 Volume expansion
    1.6 RECENT ADVANCES IN LI-S BATTERIES
        1.6.1 Sulfur cathodes
            1.6.1.1 Sulfur-carbon nanocomposites
            1.6.1.2 Sulfur-polymer nanocomposites
            1.6.1.3 Polymer-supported sulfur-carbon nanocomposites
            1.6.1.4 Li₂S cathodes
            1.6.1.5 Smaller sulfur molecules
            1.6.1.6 Selenium cathodes
            1.6.1.7 Polysulfide catholyte
            1.6.1.8 Porous and free-electrodes current-collectors
        1.6.2 Binder
        1.6.3 Electrolytes
        1.6.4 Lithium anode
        1.6.5 Separators
    1.7 APPLICATIONS
    1.8 VOCABULARY, MAIN CHARACTERISTICS
    1.9 SUMMARY
    1.10 REFERENCES
CHAPTER 2: EXPERIMENTAL APPROACHES
    2.1 CHEMICALS AND MATERIALS
    2.2 CHARACTERIZATION METHODS
        2.2.1 Scanning electron microscope (SEM)
        2.2.2 X-ray photoelectron spectroscopy (XPS)
        2.2.3 X-Ray diffraction (XRD)
        2.2.4 In-situ Ultra-violet/Visible measurements
        2.2.5 Transmission electron microscopy (TEM)
        2.2.6 Brunaeur-emmer-teller (BET)
        2.2.7 Thermogravimetric analysis (TGA)
    2.3 PREPARATION OF POROUS CARBONS (PCS) AND POLYSULFIDE (PS)
        2.3.1 Synthesis of oriented-macroporous-carbon (OMC)
        2.3.2 Preparation of dehydrated watermelon rind (WR)
        2.3.3 Preparation of starch
        2.3.4 PS preparation
    2.4 ELECTROCHEMICAL MEASUREMENT METHODS
        2.4.1 Preparation of S-loaded porous carbons (S@PCs) and cathode
        2.4.2 Cell assembly
        2.4.3 Galvanostatic cycling
        2.4.4 Cyclic voltammetry (CV)
        2.4.5 Electrochemical impedance spectroscopy (EIS)
    2.5 REFERENCES
CHAPTER 3:PERIODICAL ORIENTED-MACROPOROUS-CARBONINCORPORATED WITH Γ-AL₂O₃ FOR HIGH PERFORMANCE LI-S BATTERY
    3.1 INTRODUCTION
    3.2 RESULTS AND DISCUSSION
        3.2.1 Characterization of oriented-macroporous-carbons
            3.2.1.1 Morphology of the prepared oriented-macroporous-carbon material
            3.2.1.2 TEM investigations
            3.2.1.3 N₂ adsorption-desorption isotherms and pore distributionsmeasurements
        3.2.2 PS absorption with oriented-macroporous-carbon and XPS investigations
        3.2.3 Electrochemical performance of oriented-macroporous-carbon
            3.2.3.1 CV and galvanostatic cycleability measurements
            3.2.3.2 Electrochemical impedance spectroscopy and rate performancemeasurements
            3.2.3.3 Charge-discharge profiles and long-term cycle life
    3.3 SUMMARY
    3.4 REFERENCES
CHAPTER 4: PREPARATION AND APPLICATIONS OF MICROPOROUSCARBON DERIVED FROM BIOMASS FOR HIGH PERFORMANCE LI-SBATTERY
    4.1 INTRODUCTION
    4.2 Results and discussion
        4.2.1 Material characterization
            4.2.1.1 Morphology of WR
            4.2.1.2 N₂ absorption-desorption isotherms and pore size distributionsmeasurements
            4.2.1.3 XRD patterns and TGA investigations
        4.2.2 PS adsorption with WR
        4.2.3 Electrochemical performance
            4.2.3.1 CV profiles and galvanostatic cycleability measurements
            4.2.3.2 Electrochemical impedance spectroscopy tests
            4.2.3.3 Rate performance measurement
            4.2.3.4 Performance in soft-package batteries
    4.3 SUMMARY
    4.4 REFENRENCES
CHAPTER 5: A NOVEL INSIGHT INTO CATHODE DETERIORATION OFHIGH ENERGY LI-S BATTERY WITH HEAVY SULFUR-LOADING
    5.1 INTRODUCTION
    5.2 RESULTS AND DISCUSSION
        5.2.1 Materials and cathode characterization
            5.2.1.1 Morphology of the porous carbon
            5.2.1.2 N₂ adsorption-desorption isotherms,pore size distribution and EDXanalysis
        5.2.2 Electrochemical performance
            5.2.2.1 Performance of pressurized cathode
            5.2.2.2 Nyquist plots of pressed cell and cell appearance before and after cyclesunder an external pressure
            5.2.2.3 Electrochemical performance of the cathode with heavy S-loading underpressure
    5.3 SUMMARY
    5.4 REFERENCES
CHAPTER 6: CONCLUSIONS AND FUTURE PROSPECTIVE
    6.1 CONCLUSIONS
    6.2 FUTURE PROSPECTIVE
LIST OF FIGURES
LIST OF TABLES
LIST OF PUBLICATIONS



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