镁二次电池材料的国内外研究现状

综述了镁二次电池材料的国内外研究现状.从Mg电极在不同的电解质溶液中的电化学行为来看,除了获得一致好评的电解质Mg(AlCl2BuEt)2/THF外,国内研究了Mg(SnPh3)2/THF的性能,又尝试了复合电解质(PP13-TFSI)和(BMIMBF4)的混合,都很好得获得可逆的Mg的沉积和溶解.目前,国内、外对镁电池用的聚合物电解质(GPE)有了进一步的研究.利用PNA(聚丙烯腈)、PMMA(聚甲基丙烯酸甲酯)、PVDF(聚偏氟乙烯)和PC、EC、MgTr混合制备了GPE,同时日本合成的(PEO-PMA)-(EC-DMC)/Mg[(CF3SO2)2N]2(x-y)和PEO-PMA)-a mol%Mg(TFSI)2/EMITFSI(x-y),和韩国合成的P(VdF-co-HFP)其电导都大于10-4S·cm-1.虽然组装电池的循环性能不是很理想,但说明了GPE同样可以应用在镁电池中.从Mg正极材料的报道来看,目前大部分工作都是在开发钠米管、层状和复合材料.比如VOx/钛酸盐纳米棒、VXG/PANI复合物、VOx/PANI NCs、Cu0.1-doped VOx-NTs等,都有很好的首次放电比能量,循环性能不好的主要原因是镁负极钝化.上海交通大学尝试研究把的导电含硫材料/聚苯胺复合物做为正极材料,并组装成钮扣电池,其采用的电解质为0.25 M的Mg(AlCl2BuEt)2/THF.该钮扣电池多次循环之后放电比能量也可以达到72.7mAh/g,和锂离子电池相比,该复合物显示了较慢的Mg插入速率和较低的放电比容量,但实验结果已足够说明了导电含硫材料/聚苯胺复合物做为镁二次电池正极材料的可行性.目前紧迫的任务是,开发新型的正、负极材料,降低镁钝化电解质,开发新的负极材料,比如嵌入式的或合金负极材料.研究结果表明镁二次电池有着非常好的开发前景.     

聚1,5-二氨基蒽醌二次锂电池正极材料研究

采用化学氧化方法合成了聚1,5-二氨基蒽醌(PDAAQ)并用于二次锂电池.借助红外光谱确定其分子结构,实验测得材料的平均粒径为7.9μm,比表面积为8.9 m2.g-1,具有0.8 S.cm-1的电导率,符合作为电极材料使用的基本要求;电化学测试表明,作为二次锂电池正极材料使用时,聚合物重复单元中除了醌基团与Li+所发生的电化学氧化还原反应外,聚苯胺导电骨架也对PDAAQ的能量密度和循环性产生贡献.充放电曲线则进一步确定了聚苯胺骨架与醌基团协同作用的存在,实验表明,在Li(CF3SO2)2N/PC+DGDM电解液中,基于活性材料PDAAQ的首次放电容量达到221 mAh.g-1,经过40次充放电循环,容量保持率为80%,因此聚1,5-二氨基蒽醌具有较大应用潜力.     

硫化聚合物锂离子电池正极材料的研究进展

用单质硫对聚合物进行硫化,可以制备具有电化学活性的导电高分子材料.这些材料用作锂离子电池正极活性材料,可获得较高的比容量.综述了聚二乙基硅氧烷、聚乙烯、聚乙炔、聚苯乙烯、聚丙烯腈等聚合物通过单质硫在200～360℃下硫化所制得的导电高分子材料的电化学特性.     

新型Ni(OH)2.05电极材料的电化学性能研究

采用化学氧化法制备了碱性二次电池用正极材料Ni(OH)2.05, 考察了其作为镍氢电池正极活性材料的电化学性能. 结果表明: 以氧化处理过的样品为正极材料组装成镍氢模拟电池在0.2 C倍率下放电容量为281 mAh•g－1; 1 C充放电条件下, 270次循环后容量保持98% 以上. 交流阻抗分析和循环伏安测试表明, 经过氧化修饰的镍电极具有更小的电荷传递电阻、更快的质子扩散速度; ΔEa,c小于未处理样品70 mV, 电化学可逆性优于未处理样品; 对不同放电截止电压下的充放电测试发现: 放电截止电压进一步降低后, 相对于未处理过的样品, 氧化处理后样品无明显的二次放电平台, 第一放电平台末的容量与未处理样品二次放电平台末容量相当, 从而有效地抑制了二次放电平台现象.     

二价与四价金属离子等摩尔共掺杂的锂离子电池正极材料LiMn_(1.9)Mg_(0.05)Ti_(0.05)O_4的制备与表征

以氢氧化锂、乙酸锰、硝酸镁和钛酸丁酯为原料,以柠檬酸为螯合剂,采用溶胶-凝胶法制备了二价镁离子与四价钛离子等摩尔共掺杂的尖晶石型锂离子电池正极材料Li Mn1.9Mg0.05Ti0.05O4.采用热重分析(TGA),X射线衍射(XRD),扫描电子显微镜(SEM),透射电子显微镜(TEM)和电化学性能测试(包括循环伏安(CV)和电化学交流阻抗谱(EIS)测试)对所得样品的结构、形貌及电化学性能进行了表征.结果表明:780°C下煅烧12 h得到了颗粒均匀细小的尖晶石型结构的Li Mn1.9Mg0.05Ti0.05O4材料,该材料具有良好的电化学性能,在室温下以0.5C倍率充放电,在4.35-3.30 V电位范围内放电比容量达到126.8 m Ah·g-1,循环50次后放电比容量仍为118.5m Ah·g-1,容量保持率为93.5%.在55°C高温下循环30次后的放电比容量为111.9 m Ah·g-1,容量保持率达到91.9%,远远高于未掺杂的Li Mn2O4的容量保存率.二价镁离子与四价钛离子等摩尔共掺杂Li Mn2O4,改善了尖晶石锰酸锂的电子导电和离子导电性能,使其倍率性能和高温性能都得到了明显的提高.     

聚苯胺掺杂对C-LiFePO4复合正极材料性能的影响

应用固相反应法在惰性气氛下合成橄榄石型LiFePO4,然后制成聚苯胺掺杂C-LiFePO4复合正极材料.XRD,交流阻抗及电化学方法等测试表明,聚苯胺掺杂对LiFePO4电化学性能有一定的改善.当放电倍率为0.1C时,掺杂10%聚苯胺的(C-LiFePO4)0.9(PANI)0.1样品的放电容量达到164 mAh.g-1,且循环稳定性良好.在0.5C和1C的放电倍率下,也可以分别达到121.6 mAh.g-1和110.1 mAh.g-1的放电比容量.     

LiNi_(0.8)Co_(0.2)O_2的络合法合成及其电化学性能研究

采用络合法制备了锂离子电池的活性正极材料LiNi0.8Co0.2O2粉体,该合成材料结晶良好,层状结构发育完善.电池充放电测试表明,作为锂离子电池正极,其电化学性能与LiNi0.8Co0.2O2粉体的合成温度有关,其中以900℃下合成得到的材料性能最优:第1次放电比容量高达142mAh/g,循环30次后可逆比容量仍高达122mAh/g,容量损失为14.5%.文中对容量退化的原因进行了分析.     

可充镁电池正极材料PTMA/石墨烯

本文制备了聚4-甲基丙烯酸-2,2,6,6-四甲基哌啶-1-氮氧自由基酯(PTMA)/石墨烯纳米复合材料,并报道了其作为可充镁电池正极材料的电化学性能.通过傅里叶变换红外(FTIR)光谱、扫描电镜(SEM)、透射电镜(TEM)表征复合材料的结构和形貌;循环伏安和恒电流充放电测试其电化学性能.粒径10 nm左右的PTMA颗粒分散在具有导电作用的石墨烯表面;在"一代"电解液Mg(AlCl2BuEt)2/四氢呋喃(THF)(0.25 mol L-1)中,22.8mA g-1充放电电流密度下,PTMA/石墨烯复合材料的起始放电容量可达到81.2 mAh g-1.研究结果表明,含有自由基的有机化合物可以作为可充镁电池的一类新型正极材料,可以进一步通过使用具有高氧化分解电压的电解液来提高其放电容量.     

二次锂电池聚合物正极材料研究进展

近几十年,二次锂电池作为重要的储能装置得到迅猛发展,而开发高性能的锂电池电极材料一直是电化学能源领域的研究热点之一。与传统无机正极材料相比,聚合物正极材料具有比容量高、柔软性好、廉价易得、环境友好、加工方便、可设计性强等诸多优点。本文综述了导电聚合物、共轭羰基聚合物以及含硫聚合物正极材料的结构特点、电极反应机理、电化学性能和近五年来的重大研究进展,总结了这三类聚合物电极材料的优缺点,并重点介绍了含硫聚合物电极材料中存在的问题及改进手段,最后提出了综合这三类聚合物优点的含硫共轭导电聚合物将会是该领域的研究方向。     

苯胺-邻硝基苯胺共聚物——高比容量锂二次电池新型正极材料

聚苯胺作为锂离子电池典型的有机正极材料,合成简单、资源丰富,但其电化学比容量与循环寿命始终难以满足实用要求.作者采用化学氧化聚合法合成了苯胺-邻硝基苯胺共聚物(Poly(Aniline/o-Nitroanil-ine,P(AN-oNA)),通过在聚苯胺主链引入强拉电子基团——硝基苯胺,增大共聚物的电子共轭体系,改善共聚物链段的稳定性,利用硝基苯胺基团的电化学可逆性提高共聚物的电化学活性.结果表明,P(AN-oNA)的初始充放电比容量高达186 mAh·g-1,比聚苯胺提高近37%,60周循环仍能维持168 mAh·g-1.此外,P(AN-oNA)电极的充放电电位平阶十分接近,电极的极化明显降低,电子转移反应速率加快.这种新型共聚物结构与性能对于发展有机正极材料具有重要的参考意义.     

A new class of cathode materials for rechargeable magnesium batteries: Organosulfur compounds based on sulfur–sulfur bonds

A class of energy storage materials, organosulfur compounds with S–S bonds, has been proposed as novel cathode materials for rechargeable magnesium batteries. The cleavage and recombination of S–S bonds formed during discharge and charge process are the key components for the capacity. The cathode performance of three organosulfur materials, i.e. 2,5-dimercapto-1,3,4-thiadiazole (DMcT), poly-2,2′dithiodianiline (PDTDA) and a conductive sulfur-containing material (CMS) were characterized here. Among them, DMcT compounded with polyaniline (PAn) can provide a relatively flat discharge potential at about 1.4 V vs. Mg/Mg²⁺. PDTDA exhibits better kinetics and electrical conductivity based on the intramolecular electrocatalytic effect of the aniline moiety on thiolate anions. CMS compounded with PAn produces stable backbones to provide electrically conducting channels and higher disulfide bond content; it exhibits nearly 120 mAh/g initial discharge capacity and good capacity retention. We expect that further improvements to the capacity and cyclability will make organosulfur compounds potential cathode materials for magnesium batteries.     

Development of polymer‐based lithium secondary battery

Novel polymer composites based on polydisulfide compounds are developed as a high energy density cathode material for lithium rechargeable batteries. A polymer composite composed of 2,5‐dimercapto‐1,3,4‐thiadiazole (DMcT) and conducting polymer polyaniline (PAn) on a copper current collector provides high charge density exceeding 225Ah/kg‐cathode with average discharge voltage at 3.4V. The composite cathode showed excellent rate capability and cyclability (>500 cycles). Surface analysis and electrochemical studies indicate that a DMcT‐Cu complex plays an important role in the observed improvement of the battery performances with a copper current collector. Large increase in the charge density to 550Ah/kg‐cathode is achieved by adding elemental sulfur (S₈) to the DMcT/PAn composite cathode.     

Graphdiyne Hybrid Nanowall Arrays for High-capacity Aqueous Rechargeable Zinc Ion Battery

Development of aqueous rechargeable zinc ion battery is an important direction towards grid energy storage sought in various applications.At present,the efficient utilization of aqueous rechargeable zinc ion batteries has been seriously affected due to the defects nature of the cathode materials,such as poor capacity,limited rate performance,and limited cycle stability.Therefore,the search for high-performance cathode materials is a main challenge in this field.Herein,we in-situ prepared graphdiyne-wrapped K0.25·MnO2(K0.25·MnO2@GDY)hybrid nanowall arrays as the cathode of aqueous rechargeable zinc ion battery.The hybridnanowall arrays have obviously alleviated the pulverization and sluggish kinetic process of MnO2 cathode materials and shown high specific capacity(520 mA·h/g at a current density of 55 mA/g),which is near-full two-electron capacity.The high specific capacity was resulted from more than one Zn2+(de)intercalation process occurring per formula unit,in which we observed a structural evolution that partially stemmed from ion exchange between the intercalated K+and Zn2+ions during the discharge process.The present investigation not only provides a new material for the aqueous rechargeable Zn ion batteries,also contributes a novel route for the development of next generation aqueous rechargeable Zn ion batteries with high capacity.     

空心碳球负载二硫化硒复合材料作为锂离子电池正极材料

制备了一种空心碳球负载二硫化硒(SeS₂@HCS)复合材料作为锂离子电池正极材料。通过扫描电子显微镜(SEM),X射线衍射(XRD)以及氮气吸脱附测试(BET)等对产物形貌、组成和结构进行了表征。实验结果显示,采用模板法结合化学聚合法可以合成形貌均一、单分散的空心碳球;其直径约为500 nm,壁厚约为30 nm。进一步采用熔融灌入法可以得到空心碳球负载二硫化硒复合材料。将所制备复合材料组装成电池进行电化学性能测试,与原始二硫化硒块体材料相比,SeS₂@HCS复合材料具有更高的初始容量(100 mA·g^-1电流密度下,初始放电容量为956 mAh·g^-1)和更长的循环寿命(100 mA·g^-1电流密度下,循环200圈),同时显示出更优异的倍率性能。研究结果表明该复合材料是一种具有应用前景的新型锂离子电池正极材料。     

Disulfide-polyaniline composite cathodes for rechargeable batteries with high energy density

A composite cathode was prepared from a solution containing 2,5-dimercapto-1,3,4-thiadiazole (DMcT) and polyaniline (PAn). The resulting cathode exhibits 80% of the theoretical capacity. Furthermore, an energy density of over 600 Wh/kg-cathode and a discharge voltage of 3.4 V are obtained, when it is coupled with a lithium anode. Additional advantages of the present cathode material over the conventional metal oxides are the ease in disposal by incineration, the low pollution and the low cost. Current capability of 137 A/kg-cathode is achieved by adding a polypyrrole derivative to the DMcT-PAn composite and coupling it with a copper current collector.     

An Antiaromatic Electrode‐Active Material Enabling High Capacity and Stable Performance of Rechargeable Batteries

Although aromatic compounds occupy a central position in organic chemistry, antiaromatic compounds have demonstrated little practical utility. Herein we report the application of an antiaromatic compound as an electrode‐active material in rechargeable batteries. The performance of dimesityl‐substituted norcorrole nickel(II) complex (NiNC) as a cathode‐active material was examined with a Li metal anode. A maximum discharge capacity of about 207 mAhg^?1 was maintained after 100 charge/discharge cycles. Moreover, the bipolar redox property of NiNC enables the construction of a Li metal free rechargeable battery. The high performance of NiNC batteries demonstrates a prospective feature of stable antiaromatic compounds as electrode‐active materials.     

Cyclability of sulfur/dehydrogenated polyacrylonitrile composite cathode in lithium–sulfur batteries

Sulfur/dehydrogenated polyacrylonitrile composite has been studied as cathode material for lithium–sulfur rechargeable batteries. Nonetheless, capacity fading has been a challenge for the commercialization of batteries. In this study, characterization techniques of scanning electron microscopy, energy dispersive X-ray spectroscopy, elemental analysis, cyclic voltammetry, and electrochemical impedance spectroscopy are used to investigate the change of cathode properties with charge–discharge cycles. Elemental analysis reveals that sulfur accumulates on the surface of the composite at the end of charge, and the sulfur formation decreases with cycle number. Scanning electron microscopy observations indicate that cathode surface morphology changes significantly after several cycles. By modeling the electrochemical impedance spectra of the cell in different discharge states, we suggest that capacity fading arises mainly from the formation and accumulation of irreversible Li₂S (and Li₂S₂) on the cathode surface.     

镁二次电池正极材料纳米Fe3S4的电化学性能

首次将尖晶石相的纳米Fe₃S₄材料用作镁二次电池的正极材料。采用水热法一步合成了具有纳米结构的Fe₃S₄材料, 并采用XRD、SEM测试手段对产物的物相、形貌进行了表征。实验结果表明, 在160 ℃能够合成纯相的Fe₃S₄材料, 该材料具有银耳状纳米结构。电化学测试结果显示, 水热法合成的纳米Fe₃S₄材料能够在镁二次电池体系中进行有效的可逆充放电, 放电平台电压为0.9 V, 首次放电容量高达267 mAh·g^-1, 50次循环后衰减至110 mAh·g^-1。电化学交流阻抗测试结果表明镁离子能够在Fe₃S₄晶格中扩散。