【作者】 杨晶；

【导师】 高鑫；

【作者基本信息】 哈尔滨理工大学 ， 材料与化工（专业学位）， 2023， 硕士

【摘要】 在我国的工业化过程中,过度地对传统矿物资源进行开采,导致了环境污染与矿物资源的逐渐耗尽。超级电容器（SCs）具有高功率密度、快速充放电、循环稳定性高等优点,在储能器件应用中具有重要地位。金属有机骨架（MOFs）因其特有的高孔隙率、大比表面积、可调控孔结构及富含固有氧化还原活性位点等特点,在电化学应用领域中逐渐扮演重要角色。其中呈现中空结构的MOFs,更因其独特的空腔结构,有效地缩短了离子传输路径并且能够提供丰富的化学活性位点,而更具一定优势。因此,本文通过溶剂热反应方法制备具有独特中空微球状镍钴金属有机骨架（Ni Co-MOF）,通过对材料进行合理结构设计、找寻最佳金属离子比例和反应温度,探寻不同影响因素对其形貌结构以及电化学性能的影响。并且进一步在镍钴金属有机骨架的基础上引入具有强配位能力的锰离子,通过一步溶剂热制备镍钴锰三元金属有机骨架（Ni Co Mn-MOF）,有效改善Ni Co-MOF的循环稳定性。通过改变体系内金属离子配比以及聚乙烯吡咯烷酮（PVP）含量,探究其不同条件因素对材料形貌的结构特点影响,同时对其电化学性能进行更进一步分析。本文选取六水合硝酸镍、六水合硝酸钴作为金属离子中心,配体选用均苯三甲酸,同时选取聚乙烯吡咯烷酮为分散剂,通过溶剂热反应构建了具有中空球状结构Ni Co-MOF,其独特的中空结构能够有利与电解质离子的扩散移动,并且提供了大量的氧化还原活性位点,有效提高为了材料的比电容量。通过改变镍钴离子摩尔比以及溶剂热反应温度得出,当镍钴摩尔比为3:1、反应温度为150℃时,构建的Ni Co-MOF展现了最佳的电化学性能。在1 A g^-1的电流密度时展现909 F g^-1的比容量;在10 A g^-1时,仍保持55.3%的比电容。所构建的Ni Co-MOF//AC能够在799.9 W kg^-1的功率密度下提供的能量密度能达到28.9 Wh kg^-1。在Ni Co-MOF基础上引入锰离子,形成结构更为稳定的中空球状Ni Co Mn-MOF,其独特的中空球结构能够有利于调节由于体积膨胀所导致的在快速充放电过程中的应力问题,进而提高其循环稳定性。此外,拥有多种价态的镍钴锰离子的协同作用可以提供优良的氧化还原反应。其中当Mn²⁺添加0.1875 mmol、PVP添加量为1 g时制备的Ni₃Co₁Mn_0.5-MOF在1 A g^-1的条件下能够体现出1430 F g^-1的比电容。组装成的Ni Co Mn-MOF//AC在1 A g^-1的电流密度下拥有的比电容能够达到189.7 F g^-1,在791.65 W kg^-1的功率密度下提供的能量密度达到66.75 Wh kg^-1,即使在经过10 A g^-1的条件下进行10000次循环,仍能达到88.52%的电容保持率,并且展现了99.57%的高库伦效率。更多还原

【Abstract】 In the process of industrialization in our country,exploitation of traditional mineral resources has led to environmental pollution and depletion of mineral resources.Supercapacitors（SCs）have the advantages of high power density,rapid charge and discharge,and high cycle stability,which play an important role in the application of energy storage devices.Metal-organic frameworks（MOFs）have been playing an important role in electrochemical applications due to their characteristics of high porosity,large surface area,adjustable pore structure and abundant natural redox active sites.Among them,MOFs with hollow structure have more advantages due to their unique cavity structure,which can effectively shorten the ion transport path and provide abundant chemical active sites.Therefore,in this paper,solvothermal preparation of a unique hollow microspheroidal nickel-cobalt organic framework（Ni Co-MOF）was carried out to explore the effects of different influencing factors on its morphology,structure and electrochemical performance through reasonable structural design of the material,the optimal proportion of metal ions and reaction temperature.Furthermore,manganese ion with strong coordination ability was introduced into Ni Co Mn-MOF on the basis of nickel-cobalt organic framework,and the solvothermal preparation of nickel-cobalt-manganese ternary organic framework（Ni Co Mn-MOF）was conducted in one step,which effectively improved the cyclic stability of Ni Co-MOF.By changing the ratio of metal ions and the content of polyvinylpyrrolidone（PVP）in the system,the influence of different conditions on the structural characteristics of the material morphology was explored,and the electrochemical performance was further analyzed.In this paper,a Ni Co-MOF with hollow spherical structure was constructed by solvothermal reaction using nickel nitrate hexahydrate and cobalt nitrate hexahydrate as metal ion centers,homophthalic acid as a ligand,and polyvinylpyrrolidone as a dispersant,whose unique hollow structure can facilitate the diffusion and movement of electrolyte ions and provide a large number of redox active sites,effectively improving the specific electric capacity of the material.specific electric capacity.By varying the molar ratio of Ni Co ions and the solvothermal reaction temperature,the constructed Ni Co-MOF exhibited the best electrochemical performance when the Ni Co molar ratio was 3:1 and the reaction temperature was 150℃.It exhibits a specific capacitance of 909F g^-1 at a current density of 1 A g^-1.At 10 A g^-1,it still maintains a specific capacitance of55.3%.The constructed Ni Co-MOF//AC is capable of providing an energy density of28.9 Wh kg^-1 at a power density of 799.9 W kg^-1.The hollow spherical Ni Co Mn-MOF with a more stable structure is formed by introducing manganese ions on the basis of Ni Co-MOF.Its unique hollow spherical structure can help regulate the stress problems caused by volume expansion during rapid charging and discharging,and thus improve its cycling stability.In addition,the synergistic effect of Ni Co Mn ions possessing multiple valence states can provide excellent redox reactions.The Ni₃Co₁Mn_0.5-MOF prepared with Mn²⁺addition of 0.1875mmol and PVP addition of 1 g can exhibit a high specific capacitance of 1430 F g^-1 at 1A g^-1.The assembled Ni Co Mn-MOF//AC exhibited a specific capacitance of 189.7 F g^-1at a current density of 1 A g^-1,provided a high energy density of 66.75 Wh kg^-1 at a power density of 791.65 W kg^-1,and achieved a capacitance retention rate of 88.52%even after10,000 cycles at 10 A g^-1.and exhibits a high Coulomb efficiency of 99.57%.更多还原