Practical development and challenges of garnet-structured Li7La3Zr2O12 electrolytes for all-solid-state lithium-ion batteries: A review

All-solid-state Li-ion batteries (ASSLIBs) have been widely studied to achieve Li-ion batteries (LIBs) with high safety and energy density. Recent reviews and experimental papers have focused on methods that improve the ionic conductivity, stabilize the electrochemical performance, and enhance the electrolyte/electrode interfacial compatibility of several solid-state electrolytes (SSEs), including oxides, sulf-ides, composite and gel electrolytes, and so on. Garnet-structured Li7La3Zr2O12 (LLZO) is highly regarded an SSE with excellent application potential. However, this type of electrolyte also possesses a number of disadvantages, such as low ionic conductivity, unstable cubic phase, and poor interfacial compatibility with anodes/cathodes. The benefits of LLZO have urged many researchers to explore effective solutions to over-come its inherent limitations. Herein, we review recent developments on garnet-structured LLZO and provide comprehensive insights to guide the development of garnet-structured LLZO-type electrolytes. We not only systematically and comprehensively discuss the preparation, ele-ment doping, structure, stability, and interfacial improvement of LLZOs but also provide future perspectives for these materials. This review expands the current understanding on advanced solid garnet electrolytes and provides meaningful guidance for the commercialization of ASSLIBs.     

储能系统中梯次利用动力电池容量优化配置的研究进展

梯次利用动力电池在储能领域的应用,对于推动电力行业健康绿色发展、提高资源利用率、降低储能系统成本、推动储能系统商业化以及节能环保具有重要的社会意义和经济效益。储能系统的容量优化配置是实现最佳经济效益,不出现容量、功率缺配和超配情况的关键。对容量优化配置的最新研究动态进行综述,列举了国内外梯次利用动力电池在储能领域的应用现状,综合介绍了目前几种主要应用场景中梯次利用动力电池的容量优化配置技术,并对今后的研究方向进行讨论和展望。     

锂离子电池正极材料尖晶石型LiMn2O4的制备及电化学性能研究

首次采用基于复合络合剂柠檬酸和β-环糊精的溶胶凝胶法制备了尖晶石型锰酸锂，并研究了煅烧温度对材料电化学性能的影响。电化学性能表明，700℃煅烧制备的材料具有优异的倍率和循环性能。在3C电流下此材料的首次和第200次放电比容量分别为102mAh／g和90．8mAh／g，容量保持率为89％。     

纳米α-MnS的溶剂热合成及电化学性能研究

以锰粉和硫粉为原料,以乙二胺为溶剂,分别在180℃和160℃下,采用溶剂热法成功地合成了纳米α -MnS(对应分别记为MnS-1和MnS-2).利用XRD,SEM手段对目标产物MnS-1和MnS-2的结构和形貌进行了表征,结果表明:溶剂热法合成的样品具有单一纯相的面心立方α -MnS结构.溶剂热的温度对样品的形貌有较大...     

LiFePO4/CNT复合材料的制备及电化学性能

采用溶胶凝胶-微波法制备LiFePO4/碳纳米管(CNT)复合正极材料.考察不同微波时间和CNT含量对其电化学性能的影响,并通过X射线衍射(XRD)和扫描电子显微镜(SEM)对样品的晶型结构和表面形貌进行表征.结果表明:掺CNT量为2%(质量分数)和微波18 min所得样品有较好的电化学性能;0.1C充放电的首次放电比容量为142 mAh.g-1,第10次循环的比容量为136 mAh.g-1.     

基于自适应占空比扰动的MPPT算法研究

光伏发电系统的效率很大程度上决定于其最大功率点跟踪.在Madab/Simulink环境下,对光伏电池进行建模,通过模拟任意太阳辐射强度和环境温度,建立光伏模块特性曲线.并采用Boost电路作为DC-DC变换器完成阻抗变换,在对常规占空比扰动的MPPT算法研究基础上,提出一种自适应占空比扰动的MPPT算法.实验结果表明,...     

HEV锂离子串联电池组混合均衡策略研究

针对HEV中电池组的不一致性这一影响电池组性能、降低电池组寿命的问题,研究了多绕组变压器磁性均衡模型以及多原边绕组DC-DC均衡模型的电路和工作原理,为了得到较好的均衡效果,提出了一种2级均衡系统,第1级均衡模块采用多绕组变压器磁性均衡电路,第2级均衡模块采用多原边绕组变压器均衡电路.实验结果表明2级均衡系统有效减小了HEV中锂离子电池组充放电的不均衡性,适用于HEV混合动力汽车.     

用于回收废旧锂离子电池中Co(Ⅱ)的2种新型螯合剂的制备及其性能

以对甲基苯硫酚为原料,通过硝化、还原、重氮化等一系列反应合成4-甲基-2-羟基硫酚(A)。考察重氮化过程中NaNO2的用量、硫酸浓度、反应温度以及水解时硫酸浓度对产率的影响。在最佳影响因素下得到最高产率71.2%。通过氯磺化、还原以及最佳反应条件合成含有邻羟基苯硫酚的螯合树脂(B)。使用傅里叶红外光谱表征4-甲基-2-羟基硫酚与螯合树脂。在废旧锂离子电池浸出液中进行分批实验考察4-甲基-2-羟基硫酚与螯合树脂的性能,并且使用HCl溶液提取所螯合的Co2+。研究结果表明:螯合树脂显示良好的可循环性。     

锂离子电池用PVdF/PMMA电纺膜的制备及电化学性能

通过电纺法制备PVdF/PMMA纤维膜.电纺膜的形貌,结构和热行为分别用扫描电镜(SEM),红外(FTIR),差热扫描量热法(DSC)表征.将电纺膜浸入1 mol/L LiClO4/EC+PC (1∶1, V/V)溶液中,从而得到聚合物电解质.对聚合物电解质的电化学性能如离子电导率,电化学稳定性,界面阻抗和电池性能也进行了研究.结果表明,PMMA的加入增加了聚合物电解质的离子电导率,提高了聚合物电解质的电化学稳定性.PVdF/PMMA聚合物电解质的室温离子电导率高达3.5 mS/cm,电化学稳定性达5.1 V.PMMA的加入降低了界面阻抗.另外,由PVdF/PMMA聚合物电解质组装的Li/PE/LiFePO4电池具有良好的循环性能.试验表明,电纺法可能很有希望应用于制备微孔PVdF/PMMA聚合物电解质.     

Synthesis and electrochemical characteristics of xLi2MnO3·(1−x)Li-(Ni1/3Co1/3Mn1/3)O2 compounds

xLi₂MnO₃·(1−x)Li(Ni_1/3Co_1/3Mn_1/3)O₂ (x=0.25, 0.40, 0.55) compounds were prepared by low-heating solid state reaction. In the voltage range of 2.70-4.35 V, the discharge capacity of the electrode decreased with the increase of x, with a better cyclability. However, when cycled between 2.7 and 4.6 V, the cathodes delivered much larger capacities and their capacities increased with the introduction of Li₂MnO₃. Moreover, it was found that the discharge capacity gradually increased with the cycle number. The reason for this phenomenon was discussed. It was found that the relatively low cut-off potential made the activation of the Li₂MnO₃ component in the compound a gradual process, which caused the increasing capacity.