金属有机骨架前驱体法制备多孔电极材料及其电化学储能性能的研究
发布时间：2018-10-15 20:34
【摘要】：伴随着经济的快速发展,能源危机和环境污染的加剧迫切要求寻找清洁替代能源及其相关能量存储和转化技术。多孔碳、多孔氧化物及其复合材料是广泛应用于超级电容器和锂离子电池的电极材料。通常多孔材料的制备方法包括自组装法、纳米铸造法和模板法等,其中模板法又分为软模板和硬模板法。金属有机骨架(MOFs)前驱体法合成多孔功能材料属于硬模板法的一种,具有方法简单、成本低、可控性强等优点。该方法也是一种制备特殊微纳米结构电极材料的有效方法,通过对电极材料微观结构的调控和设计可以有效的提高电化学储能性能。本论文旨在研究开发一种以MOFs为前驱体,通过离子掺杂或高温碳化等方法来可控设计有机金属骨架、多孔碳、多孔氧化物及其复合电极材料的方法,以期能进一步提高材料的电化学储能性能。主要研究内容如下:首先以溶剂热法制备了粒径在1～2 μm的MOF-5立方体颗粒,以其为前驱体在惰性气氛下进行高温炭化处理,得到保留前驱体形貌的分级孔结构ZnO/C复合材料。900℃下处理得到ZnO/C复合材料(ZC-900)的比表面积为2214.9 m2g-1,平均孔径为3.5 nm。将该复合材料作为电极材料测试了其在1MKCl的电解液中的电容性能,研究了热处理温度,形貌和孔径分布对电容性能的影响。电化学测试表明,ZC-900在10mVs-1下的比电容为206.3 F/g,在4A/g的电流密度下循环1000次后电容保持率为96.5%,表现出良好的循环寿命。可见高的介孔孔容和比表面积表现出较高的比电容和循环稳定性。通过一步溶剂热法制备了不同Ni掺杂量的FeNi-MIL88B-x(0≤x≤2.5)微纳米棒。随着Ni/Fe比的增加,孔道结构从致密相向开孔相转变,说明此时Ni2+取代了 MOFs骨架中的部分Fe3+,使晶格常数有所增加。同时添加Ni离子有效减小了微纳米棒的大小。电化学研究表明,随着镍离子掺杂量的增加,比电容从62F/g增加到230F/g(10mV/s)。锂电测试结果表明:在100mAh/g电流密度下FeNi-MIL88B-0.5首次放电容量达到了 490 mAh/g较Fe-MIL88B(370 mAh/g)提升了32%。为了研究基于MOFs前驱体多孔材料的电容性能,对MIL88B(Fe)和MIL88B(FeNi)样品分别进行不同温度炭化处理制备金属氧化物与碳的复合材料。XRD研究表明,600℃碳化分别得到Fe2O3/C和NiFe2O4/C复合材料,900℃则分别获得Fe/Fe3O4/C和FeNi/NiFe2O4/C复合材料。电化学分析结果表明:炭化后样品较前驱体具有更加优异的比电容和电容保持率。其中FeNi/NiFe2O4/C复合材料比电容达到163.5 F/g(10 mV/s),随扫速由10 mV/s增加至100 mV/s的电容保持率为87.15%。炭化复合材料优异的性能归因于电极材料均匀的颗粒度和纳米尺寸,保证了电解质溶液和电极材料的充分接触,缩短了离子的扩散距离。采用溶剂热法制备了基于甲酸配体的(Co、Mn、Ni)-MOFs及其双金属掺杂固溶体,系统研究了掺杂固溶体MOFs电极材料的电化学性能。电化学性能研究表明,[Ni3(HCOO)6]在10mV/s的扫速下的比电容达到 535 F/g,高于[Co3(HCOO)6](318.8F/g)和[Mn3(HCOO)6](180.5 F/g)。对于混合金属甲酸配体的MOFs材料,以CoNi-MOFs为例,CoxNi1-x(HCOO)6比电容明显优于单一金属甲酸配体的MOFs材料的比电容,其中[Co1.5Ni1.5(HCOO)6]比电容达到888.8 F/g(10mV/s)。对甲酸配体MOFs进行锂电测试,在100 mA/g的电流密度下,[CO1.5Ni1.5(HCOO)6]首次放电容量为1515 mAh/g 优于[Co3(HCOO)6](1181 mAh/g)和[Ni3(HCOO)6](1020 mAh/g)比容量。
[Abstract]:Along with the rapid development of economy, the intensification of energy crisis and environmental pollution urgently need to find a clean alternative energy source and its related energy storage and transformation technology. the porous carbon, the porous oxide and the composite material thereof are electrode materials which are widely applied to super capacitors and lithium ion batteries. Generally, the preparation method of porous material includes self-assembly method, nano-casting method and template method, wherein the template method is divided into soft template and hard template method. The metal organic framework (MOFs) precursor synthesis porous functional material belongs to a hard template method, and has the advantages of simple method, low cost, strong controllability and the like. The method is also an effective method for preparing special micro-nano structure electrode materials, and the electrochemical energy storage performance can be effectively improved through the regulation and design of the micro structure of the counter electrode material. The purpose of this paper is to develop a method for designing organic metal skeleton, porous carbon, porous oxide and composite electrode material by using MOFs as a precursor and by ion doping or high temperature carbonization, so as to further improve the electrochemical energy storage performance of the material. The main research contents are as follows: firstly, a MOF-5 cubic particle with a particle size of 1 to 2. m u.m is prepared by a solvent thermal method, and the precursor is subjected to high-temperature carbonization treatment under an inert atmosphere; The specific surface area of ZnO/ C composites (ZC-900) was 2214. 9 m2g-1 at 900 鈩，
本文编号：2273760
[Abstract]:Along with the rapid development of economy, the intensification of energy crisis and environmental pollution urgently need to find a clean alternative energy source and its related energy storage and transformation technology. the porous carbon, the porous oxide and the composite material thereof are electrode materials which are widely applied to super capacitors and lithium ion batteries. Generally, the preparation method of porous material includes self-assembly method, nano-casting method and template method, wherein the template method is divided into soft template and hard template method. The metal organic framework (MOFs) precursor synthesis porous functional material belongs to a hard template method, and has the advantages of simple method, low cost, strong controllability and the like. The method is also an effective method for preparing special micro-nano structure electrode materials, and the electrochemical energy storage performance can be effectively improved through the regulation and design of the micro structure of the counter electrode material. The purpose of this paper is to develop a method for designing organic metal skeleton, porous carbon, porous oxide and composite electrode material by using MOFs as a precursor and by ion doping or high temperature carbonization, so as to further improve the electrochemical energy storage performance of the material. The main research contents are as follows: firstly, a MOF-5 cubic particle with a particle size of 1 to 2. m u.m is prepared by a solvent thermal method, and the precursor is subjected to high-temperature carbonization treatment under an inert atmosphere; The specific surface area of ZnO/ C composites (ZC-900) was 2214. 9 m2g-1 at 900 鈩，
本文编号：2273760
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