【作者】 李想；

【导师】 李志国；

【作者基本信息】 东北林业大学 ， 生物材料工程， 2023， 博士

【摘要】 随着社会的快速发展,对化石燃料的持续消耗造成了严重的环境污染,并对全球气候变化产生了重要的影响。近年来,对太阳能、水电和生物能源等可持续能源的探索,以及开发相应的能源储存和转换技术变得越来越深入。在不同的储能技术中,电化学储能系统已被认为是最实用、可靠和高效的选择,包括锌离子电池、金属空气电池和超级电容器。然而,当前储能技术的能量密度、寿命和可靠性等方面仍难以足以满足日益增长的实际应用需求,亟需在电极材料设计等方面开展进一步的探索。目前,生物质碳/复合材料因其独特的易调节结构、良好的电子传导性、天然的丰富性和环境友好而受到研究人员越来越多的关注,使其有希望成为电化学储能装置的电极组成材料。电化学储能装置的性能主要取决于电极材料,通过设计构建特定形貌的生物质衍生碳电极材料以全面提升电化学性能和循环稳定性是当下所面临的问题,并有望扩展其应用领域。论文以生物质衍生物—糠醛做为主要原料,采用席夫碱反应通过一步水热碳化法合成了具有特殊形貌的水热碳材料。在此基础上,通过化学活化调节孔道结构,并进一步与电化学活性金属氧化物进行复合,构建了不同水系锌离子碳基储能电极材料。所构建的具有特殊形貌和多孔结构的生物质衍生碳材料,其形貌结构可以作为电解质的蓄水池储存更多的电解质,丰富的孔径结构和高的比表面积可以缩短电解质的传输距离,使电解质离子快速传输,提升了储能增强了稳定性,并扩大到低温应用领域。主要研究内容如下:（1）以生物质衍生物糠醛为碳源,以含氮结构的不同胺类为氮源,通过前驱体分子中醛基和氨基之间的席夫碱反应来调节碳源前驱体亲水性和疏水性之间的差异,采用一步水热碳化法制备出具有特殊形貌的碳颗粒,系统考察了反应条件如反应物摩尔比、反应时间、反应温度对水热碳材料形貌和微观结构的影响,并提出了不同形貌糠醛基碳材料的水热合成机制。通过FTIR、拉曼光谱、氮气吸附脱附测试等研究了所制备碳材料的微观结构、晶体结构、比表面积和孔径分布等。其中,以糠醛为碳源和三聚氰胺为氮源在反应时间约为16 h,反应温度为180℃,摩尔比为1:2时,可制备得到尺寸均匀（颗粒直径约为2-3μm）、纳米片状包裹的氮氧共掺杂“杨梅状”球形碳颗粒。（2）采用一步活化法制备了具有独特“杨梅状”结构的氮掺杂多孔碳材料,考察了活化工艺对“杨梅状”氮掺杂多孔碳材料形貌、化学组成以及孔隙结构的影响。NO-CPC-750的比表面积达到1151.3 m² g^-1,平均孔隙尺寸为0.91 nm,具有较高的有效孔占比为85.29%,与Zn²⁺水合直径相匹配。所制备的“杨梅状”氮掺杂多孔碳材料具有独特的形貌,有利于电解质在纳米片层内部储存,缩短电解质的传输距离,可展现出优异的电化学性能。通过使用2 M ZnSO₄电解质将NO-CPC-750进行锌离子混合超级电容器组装,其拥有高容量(电流密度为0.1 A g^-1时为122.3 mAh g^-1),大能量/功率密度(97.78 Wh kg^-1/8000 W kg^-1),以及在连续10000次充放电循环后优异的循环稳定性（电容保持率为98%）。并且NO-CPC-750//Zn表现出卓越的低温性能和可操作性(-30℃时为78.27 mAh g^-1,在-20和20℃之间的三次循环稳定性没有性能下降)。这项研究提出了一种新的碳电极结构设计策略,可以促进多价离子的扩散和传输。（3）在课题组前期研究的形貌规整纳米花状球形碳颗粒基础上,通过一步活化法制备了纳米花状多孔碳材料,探究了在不同活化温度下纳米花状多孔碳材料表面形貌及电化学性能。进一步利用多孔纳米花状结构在其表面进行一步水热包覆金属氧化物五氧化二钒,制备了V₂O₅/纳米花状碳电极材料,考察了不同水热温度下V₂O₅/纳米花状碳电极材料的形貌及电化学性能。当水热温度为180℃所得的V₂O₅-180纳米花状碳电极组装成锌钒电池在电流密度为50 mA g^-1下表现出高可逆比容量244.35 mAh g^-1,经过2000次循环后,V₂O₅-180仍能保持原有97.5%的比容量,库仑效率接近98%,表明V₂O₅-180作为锌钒电池正极材料拥有良好的电化学可逆性和优异的循环稳定性。此外,在-20℃条件下,所构建的锌离子电池比容量值达到171 mAh g^-1,比容量保持率为70%,这为探究电极形貌特征对水系锌离子电池性能的影响提供了有益借鉴和指导。（4）进一步利用活化“杨梅状”多孔碳为载体,在碳颗粒生成水热合成过程中原位引入金属锰氧化物,设计合成了一种MnO₂包覆的“杨梅状”多孔碳颗粒。通过控制KMnO₄不同添加量考察了MnO₂包覆的“杨梅状”多孔碳颗粒的形貌、晶格结构及电化学特性。在水热温度为140℃加入KMnO₄为30 mM时,MnO₂/NC-30-140样品表现出更高的比表面积为332.14 m² g^-1和较大的孔体积为0.44 cm³ g^-1。MnO₂/NC-30-140作为正极材料与锌箔组装成锌锰电池时,在电流密度为50 mA g^-1下表现出高可逆比容量(251 mAh g^-1)以及优异的能量密度(225.9 Wh kg^-1)。在电流密度为0.5 A g^-1下经过3000次循环后,其仍能保持98.62%的比容量,库仑效率99%。由于MnO₂/“杨梅状”碳电极独特的形貌和孔道特征有利于电解质快速传输。因此在低温条件下（-20℃）,所组装构建的水系锌离子电池展现出优异的电化学可逆性(比容量值达到181 mAh g^-1,保持率为72%)。（5）为抑制锌枝晶生长以改善水系锌离子电池的应用稳定性,论文在“杨梅状”碳材料表面通过化学镀方法构建了Zn/“杨梅状”碳负极材料,以进一步考察电极形貌效应对锌离子电池电化学性能及其稳定性的影响。结果表明化学镀锌添加比例对电极材料微观结构和锌枝晶生长有显著影响,优化后所制备的Zn-1:2负极材料比表面积可达127.86 m² g^-1,最大孔体积为0.39 cm³ g^-1。值得注意的是,作为水系锌离子电池锌负极,由于其形貌效应使得锌枝晶生长方向改变,从而改善了由于枝晶生长对隔膜的破坏,进一步提升电化学性能以及循环稳定性。由负极Zn-1:2与MnO₂/“杨梅状”碳正极组装成锌锰电池,在电流密度为50 mA g^-1下展现出高的可逆比容量(243 mAh g^-1),而且经过4000次循环后,其仍能保持97%的比容量,库仑效率高达97.5%,显著提升了水系锌离子电池的循环稳定性。电极材料独特的形貌特征使所构建的锌锰电池在低温下仍展现出良好的电化学行为(-20℃,比容量达到165 mAh g^-1,保持率为68%)。更多还原

【Abstract】 With the rapid development of society,the continued energy consumption of fossil fuels is causing serious environmental pollution problems and has significant impact on global climate change.In recent years,the search for sustainable energy sources such as solar,hydropower and bioenergy,and the development of corresponding energy storage and conversion technologies has become increasingly intensive.Among the different energy storage technologies,electrochemical energy storage systems have been considered the most practical,reliable and efficient option,including zinc-ion batteries,metal-air batteries and supercapacitors.However,the energy density,lifetime and reliability of current energy storage technologies are still not sufficient to meet the growing demand for practical applications,and further exploratory research in electrode material design and other areas is urgently needed.Currently,biomass carbon/composites are receiving increasing attention from researchers due to their unique easily adjustable structure,good electronic conductivity,natural abundance and environmental friendliness,making them promising materials for electrode composition in electrochemical energy storage devices.The performance of electrochemical energy storage devices is largely dependent on the electrode material,and the design of biomass-derived carbon electrode materials with specific morphologies to enhance the overall electrochemical performance and cycling stability is the issue at hand,and promises to expand its application areas.In this thesis,biomass-derived furfural was used as the main raw material for the synthesis of hydrothermal carbon materials with special morphology by one-step hydrothermal carbonisation using Schiff base reaction.On this basis,the pore structure was adjusted by chemical activation and further compounded with electrochemically active metal oxides to construct different aqueous zinc ion-carbon based energy storage electrode materials.The constructed biomass-derived carbon materials with special morphology and porous structure have morphological structure that can be used as reservoir for electrolyte to store more electrolyte,and the rich pore structure and high specific surface area can shorten the electrolyte transport distance and enable rapid electrolyte ion transport,enhancing energy storage enhancing stability and expanding to low temperature applications.The main studies are as follows:（1）The carbon particles with special morphology were prepared by one-step hydrothermal carbonization method using the biomass derivative furfural as the carbon source and different amines containing nitrogen structure as the nitrogen source,and the difference between hydrophilic and hydrophobic carbon precursors was adjusted by the Schiff base reaction between the aldehyde and amino groups in the precursor molecules.The effects of reaction conditions such as molar ratio of reactants,reaction time and reaction temperature on the morphology and microstructure of hydrothermal carbon materials were systematically investigated,and the hydrothermal synthesis mechanism of furfural-based carbon materials with different morphologies was proposed.The microstructure,crystal structure,specific surface area and pore size distribution of the prepared carbon materials were investigated by FTIR,Raman spectroscopy and nitrogen adsorption and desorption tests.Among them,nitrogen-oxygen co-doped waxberry-like spherical carbon particles with uniform size（particle diameter of about 2-3μm）and nanosheet wrapping could be prepared by using furfural as the carbon source and melamine as the nitrogen source at reaction time of about 16 h,reaction temperature of 180℃and molar ratio of 1:2.（2）Nitrogen-doped porous carbon materials with unique"waxberry-like"structure were prepared by one-step activation method,and the effects of the activation process on the morphology,chemical composition and pore structure of the"waxberry-like"nitrogen-doped porous carbon materials were investigated.NO-CPC-750 possessed BET specific surface area of 1151.3 m² g^-1,average pore size of 0.91 nm and high effective pore percentage of 85.29%,which matched the hydration diameter of Zn²⁺.The"waxberry-like"nitrogen-doped porous carbon material has unique morphology,which facilitates the storage of electrolyte inside the nanosheets and shortens the electrolyte transport distance,and exhibits excellent electrochemical properties.By assembling the NO-CPC-750 with zinc ion hybrid supercapacitor using 2 M ZnSO₄ electrolyte,it has high capacity(122.3 mAh g^-1 at current density of 0.1 A g^-1),high energy/power density(97.78 Wh kg^-1/8000 W kg^-1)and excellent cycling stability（98% capacitance retention）after 10,000 consecutive charge/discharge cycles.The assembled NO-CPC-750//Zn also exhibits excellent low temperature performance and operability(78.27 mAh g^-1 at-30℃,with no performance degradation over three cycles of stability between-20 and 20℃).This study proposes a new design strategy for carbon electrode structures that can facilitate the diffusion and/or transport of multivalent ions.（3）The nano porous carbon material was prepared by one-step activation method on the basis of the morphologically regular nano flower-like spherical carbon particles studied by the group previously.The surface morphology and electrochemical properties of nano flower-like carbon electrode materials were investigated at different hydrothermal temperatures.The V₂O₅/nano flower-like carbon electrode material was further prepared by hydrothermally coating the metal oxide vanadium pentoxide on its surface in one step using porous nano flower-like structures.The morphology and electrochemical properties of V₂O₅/nano flower-like carbon electrode materials at different hydrothermal temperatures were investigated.The V₂O₅-180 nano flower-like carbon electrode assembled into zinc-vanadium battery at hydrothermal temperature of 180℃ exhibited high reversible specific capacity of 244.35 mAh g-1 at current density of 50 mA g^-1,and after 2000 cycles V₂O₅-180 was still able to maintain its original specific capacity of 97.5%with Coulombic efficiency of nearly 98%,indicating that V₂O₅-180 has good electrochemical reversibility and excellent cycling stability as the cathode material for zinc-vanadium batteries.In addition,the specific capacity value of the constructed zinc ion battery reached 171 mAh g^-1 at-20℃ with specific capacity retention rate of 70%,which provides useful reference and guidance for investigating the influence of electrode morphological characteristics on the performance of aqueous zinc ion batteries.（4）The MnO₂-coated"waxberry-like"porous carbon particle was further designed and synthesized using activated"waxberry-like"porous carbon as carrier and introducing manganese oxides in situ during the hydrothermal synthesis of the carbon particles.The morphology,lattice structure and electrochemical properties of the MnO₂-coated"waxberry-like"porous carbon particles were investigated by controlling the addition of KMnO₄ in different amounts.The MnO₂/NC-30-140 sample exhibited higher surface area of 332.14 m² g^-1 and larger pore volume of 0.44 cm³ g^-1 when added with 30 mM KMnO₄ at hydrothermal temperature of 140℃ to form Zn-Mnbattery at current density of 50 mA g^-1.MnO₂/NC-30-140 as the cathode material assembled with zinc foil to form zinc-manganese battery exhibited high reversible specific capacity(251 mAh g^-1)and excellent energy density(225.9 Wh kg^-1).After 3000 cycles at current density of 0.5 A g^-1,MnO₂/NC-30-140 maintains its original specific capacity of 98.62%and coulombic efficiency of nearly 99%,which due to the unique morphology and pore characteristics of the MnO₂/"waxberry-like"carbon electrode,which facilitate rapid electrolyte transport.Thus,the assembled aqueous zinc ion battery exhibits excellent electrochemical reversibility(specific capacity value of 181 mAh g^-1 and retention rate of 72%)at low temperatures（-20℃）.（5）In order to inhibit the growth of Zn dendrites to improve the stability of aqueous Zn-ion batteries,the paper constructs Zn/"waxberry-like"carbon anode materials by chemical plating on the surface of"waxberry-like"carbon materials to further investigate the effect of electrode morphology on the electrochemical performance and stability of Zn-ion batteries.The results show that the chemical galvanization addition ratio has a significant effect on the microstructure and zinc dendrite growth of the electrode material.The optimized Zn-1:2 anode material has specific surface area of 127.86 m² g^-1 and maximum pore volume of 0.39 cm³ g^-1.Notably,the morphological effect of the zinc anode as an aqueous zinc ion battery changes the direction of zinc dendrite growth,thus improving the damage to the diaphragm due to dendrite growth and further enhancing the electrochemical performance as well as the cycling stability.The zinc-manganese battery assembled from Zn-1:2 anode and MnO₂/"waxberry-like"carbon cathode exhibits high reversible specific capacity(243 mAh g^-1)at current density of 50 mA g^-1and maintains specific capacity of 97%after 4000 cycles with coulombic efficiency of 97.5%.The cycling stability of the aqueous zinc ion battery is significantly enhanced.The unique morphological characteristics of the electrode material enable the constructed Zn-Mnbattery to exhibit good electrochemical behaviour even at low temperatures(-20℃,specific capacity of165 mAh g^-1,retention rate of 68%).更多还原