QIBEBT-IR  > 先进界面技术研究组
Keyword全固态电池 固态电解质 电导率 固体氧化物燃料电池 阴极
Subject Area生物学
Other AbstractSolid state electrolyte is one of key components for all solid state lithium ion batteries, which greatly determines the power density, cycle stability, safety performance, high and low temperature performance and the life of batteries. Herein, to improve the electrochemical performance and stability of solid state electrolyte, the preparation process for electrolyte materials and electrolytes was optimized. Moreover, the optimum process was identified. Meantime, in order to reduce the polarization resistance of intermediate temperature solid oxide fuel cell, the intrinsic properties and microstructure of cathode materials were optimized, and thus the cathode performance was improved. The main conclusions of this paper can be sumarried as follows: 1. The Li1.3Al0.3Ti1.7(PO4)3 (LATP) electrolyte materials with NASICON structure were prepared via a modified Pechini synthesis method. By optimizing the preparation process parameters, such as dispersant, calcination temperature for electrolyte powders, sintering temperature and period for electrolyte pellets, the high performance LATP electrolyte was obtained with the highest electrical conductivity of 6.0 x 10-4 S/cm at 303 K, which is comparable to those reported in references. The excellent electrochemical performance is due to the high densification of electrolyte with the relative density of 95.76%. Additionally, the electrolyte has a negligible electronic conductivity, whose value is only 1.2 x 10-8 S/cm. 2. In order to inhibit the reaction between LATP electrolyte and Li anode, a Li1.3Al0.3Ge1.7(PO4)3 (LAGP) barrier layer was constructed on the surface of LATP electrolyte substrate to form a LATP/LAGP double-layer electrolyte via a simple and inexpensive dry-pressing technique. A dense and smooth solid state electrolyte with dense structure can be obtained using the LAGP starting materials sintered at 650 °C, which is due to the good sintering match between LAGP layer and LATP substrate. The electrolyte exhibited excellent electrochemical performances and stability. Its electrical conductivity at room temperature is 3.4 x 10-4 S/cm, and the value of electronic conductivity is 9.6 x 10-9 S/cm. When the electrolyte was placed in the air for a long time or contacted with Li metal, its electrochemical properties were not attenuated. The assembled LiFePO4 (LFP) battery showed the first charge and discharge capacities of 142 mAh/g and 130.6 mAh/g. After 3 cycles, the capacities was increased to 145.3 and 141.4 mAh/g. 3. A series of perovskite-type La0.3Sr0.7T1-xCoxO3 (LSCT, x=0.1-0.8) cathode materials for solid oxide fuel cells were synthesized via a convenient modified sol-gel method. By optimizing the content of Co dopant, high perforamce cathode materials were obtained. The LSCT cathode with “x= 0.8” has the best electrochemical performance, achieving the polarization resistances of 1.12, 0.40 and 0.15 Ω cm2 at 550, 600 and 650 °C, and the activation energy of the LSCT cathode was 1.435 eV, which was attributed to the enhancement of the molecular oxygen dissocation and charge transfer process in the cathode.
Abstract锂离子固态电解质作为全固态电池的关键组件之一,其性能很大程度决定了电池的功率密度、循环稳定性、安全性能、高低温性能以及使用寿命。本文通过合理优化电解质材料及电解质的制备工艺来提高电解质的电化学性能及稳定性,并确立了电解质制备的最佳工艺。同时,针对中低温固体氧化物燃料电池阴极极化电阻大的问题,对阴极材料的特性及微观结构进行了优化,提高了阴极的电化学性能。 本文的主要结论如下: 1. 采用一种改良的Pechini合成方法制备了NASICON结构的Li1.3Al0.3Ti1.7(PO4)3(LATP)电解质材料。通过优化制备工艺参数,如分散剂、粉体的烧结温度、电解质片烧结温度和时间,制备出了高性能LATP电解质。电解质在303 K下的最高电导率为6.0×10-4 S/cm,高于大多数文献报道的结果,其良好的性能归因于电解质致密的结构,其致密度高达95.76%,而且该电解质具有可忽略的电子电导率,其数值仅为1.2 ×10-8 S/cm。 2. 为了抑制LATP电解质与Li负极的反应,通过一种简单廉价的干压技术在LATP电解质基体表面构筑了Li1.3Al0.3Ge1.7(PO4)3(LAGP)阻隔层,形成了LATP/LAGP双层电解质。650 °C合成的LAGP与LATP基体烧结行为匹配,制备的双层电解质表面平整、光滑、结构致密。制备的电解质具有良好的电化学性能及稳定性,室温电导率为3.4×10-4 S/cm,电子电导率数值为9.6×10-9 S/cm,在空气中长时间放置以及与Li金属接触,电化学性能均未衰减。组装了LiFePO4(LFP)电池,在0.1C电流下,电池的首次充放电容量为142.0 mAh/g和130.6 mAh/g,3次循环后,容量分别增至145.3和141.4 mAh/g。 3. 采用一种改良的溶胶凝胶法合成了一系列La0.3Sr0.7T1-xCoxO3 (LSCT, x=0.1-0.8)阴极材料,通过优化Co的掺杂量,获得了高性能的阴极材料,当x=0.8时,阴极在550 °C、600 °C、650 °C下的极化电阻数值分别为1.12、0.40和0.15 Ω cm2,活化能为1.435 eV,良好的电化学性能主要归因于电极内部氧的解离和电荷传输能力的提高。
Document Type研究报告
Recommended Citation
GB/T 7714
赵二庆. 全固态电池材料的制备及性能研究. 2016.
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