全固态薄膜锂离子电池

本文介绍了聚合物薄膜锂电池以及全固态无机薄膜锂电池,主要对全固态无机薄膜锂电池的发展过程以及其阴极材料、阳极材料、无机固态电解质的性能和制备技术进行了综述;同时介绍了全固态薄膜锂电池结构的研究,并提出了全固态薄膜锂电池现阶段研究存在的问题以及一些解决办法.     

Optimization of the cathode porosity via mechanochemical synthesis with carbon black

Journal of Solid State Electrochemistry - Nanostructured carbon–coated composite cathode materials LiFe0.5Mn0.5PO4/C (LFMP/C) are prepared by the mechanochemically assisted solid-state...     

动力锂离子电池正极材料磷酸钒锂制备方法

锂离子电池新型正极材料的开发是当前的研究热点,其中磷酸盐材料以其结构稳定、安全性能好及资源丰富等优点备受关注。磷酸钒锂理论能量密度可达500mWh/g,具有较高的电子离子导电性、理论充放电容量及充放电电压平台,被认为是一种极具竞争优势和应用前景的动力锂离子电池正极材料。传统磷酸钒锂合成方法有固相合成法、碳热还原法、溶胶凝胶法和水热合成法等,近年来,又出现了湿法固相配位法、微波固相合成法和流变相法等新型合成方法。本文简要介绍了磷酸钒锂的结构和性能特点,对磷酸钒锂制备方法的最新研究进展进行了较为全面的阐述,并详细介绍了本研究团队近年来在磷酸钒锂材料新型合成方法方面的探索成果。同时对各种合成方法的制备工艺及材料性能进行了对比分析,并探讨了当前存在的问题及未来的研究方向。     

Recent advances in cathodes for all-solid-state lithium-sulfur batteries

Lithium-sulfur (Li-S) batteries have been regarded as the candidate for the next-generation energy storage system due to the high theoretical specific capacity (1675 mAh/g), energy density (2600 Wh/kg) and the abundance of elemental sulfur, but the application of Li-S batteries is impeded by a series of problems. Recently, all-solid-state Li-S batteries (ASSLSBs) have drawn great attention because many drawbacks such as safety issues caused by metallic lithium anodes and organic liquid electrolytes can be overcome through the use of solid-state electrolytes (SEs). However, not only the problems brought by sulfur cathodes still exist, but more trouble arouses from the interfaces between SEs and cathodes, hampering the practical application of ASSLSBs. Therefore, in order to deal with the problems, enormous endeavors have been done on ASSLSB cathodes during the past few decades, including engineering of cathode active materials, cathode host materials, cathode binder materials and cathode structures. In this review, the electrochemical mechanism and existing problems of ASSLSBs are briefly introduced. Subsequently, the strategies for developing cathode materials and designing cathode structures are presented. Then there follows a brief discussion of SE problems and expectations, and finally, the challenges and perspectives of ASSLSBs are summarized.     

预嵌锂硬碳和软碳用于锂离子电容器负极的比较研究

锂离子电容器是一种应用前景广阔的电化学储能器件. 目前,活性炭作为锂离子电容器正极被广泛使用. 然而,锂离子电容器负极却有多种不同选择,如硬碳和软碳等碳材料. 本文使用两种具有不同结构和电化学特性的硬碳和软碳材料作为锂离子电容器负极,进行了对比研究. 研究表明,软碳相比于硬碳有更好的电子导电性和更高的可逆容量. 通过在电流范围0.1 ~ 12 A·g^-1下进行充放电测试,分别研究了两种碳基电极在不同涂覆厚度下的倍率性能. 结果显示,硬碳电极在大电流下有更好的倍率特性. 然后,以活性炭为正极,预嵌锂的硬碳和软碳为负极,锂片为锂源和参比电极,分别组装了三电极软包锂离子电容器. 根据三电极充放电测试,分别研究了不同预嵌锂量的硬碳和软碳所组装的锂离子电容器的电化学性能. 结果表明,合适的负极预嵌锂容量可以提升锂电容的能量密度、功率密度和循环稳定性. 最后,大容量硬碳和软碳基软包锂离子电容器被分别组装,软碳基锂电容实现了最高的能量密度21.2 Wh·kg^-1（基于整个器件质量）,硬碳基锂电容实现最高的功率密度5.1 kW·kg^-1.     

多电子反应材料推动高能量密度电池发展：材料与体系创新

全球能源结构转型推动了电化学储能系统的飞速发展,提高能量密度是发展新型二次电池的重要方向和研究热点。然而,受限于传统的嵌入式反应,锂离子电池在能量密度上已经逐渐达到极限。要发展更高能量密度的新型二次电池,需要在新理论、新材料和新体系上进行突破。基于此,本文总结了20年来多电子反应材料概念的形成、理论的发展、材料创制的历程。在“轻元素多电子反应”和“多离子效应”核心设计准则的指导下,具有上述特征的电极材料与电池结构不断发展迭代,引领了高能量密度电池的发展方向。从阳离子氧化还原到阴阳离子协同氧化还原,从嵌入式反应到合金化反应,从传统有机液态体系到电池固态化,本文梳理了典型的多电子反应正负极材料的结构特性、体系创新和工程化前景,剖析了多电子反应电极材料的瓶颈问题,并分析了电池固态化发展所面临的挑战。最后,对高能量密度电池的未来发展趋势和难点进行了归纳与展望。     

基于一体化正极与电解质膜的高性能固态电池

Lithium ion batteries (LIBs) are becoming the most popular energy storage systems in our society. However, frequently occurring accidents of electrical cars powered by LIBs have caused increased safety concern regarding LIBs. Solid-state lithium batteries (SSLBs) are believed to be the most promising next generation energy storage system due to their better in-built safety mechanisms than LIBs using flammable organic liquid electrolyte. However, constructing the ionic conducting path in SSLBs is challenging due to the slow ionic diffusion of Li ion in solid-state electrolyte, particularly in the case of solid-solid contact between the solid materials. In this paper, we demonstrate the construction of an integrated electrolyte and cathode for use in SSLBs. An integrated electrolyte and cathode membrane is obtained via simultaneous electrospinning and electrospraying of a polyacrylonitrile (PAN) electrolyte and a LiFePO₄ (LFP) cathode material respectively, for the cathode layer, followed by the electrospinning of PAN to prepare the electrolyte layer. The resultant integrated PAN-LFP membrane is flexible. Scanning electron microscopy and energy dispersive X-ray spectroscopy measurement results show that the electrode and electrolyte are in close contact with each other. After the integrated PAN-LFP membrane is filled with a succinonitrile-bistrifluoromethanesulfonimide (SN-LiTFSI) salt mixture, it is paired with a lithium foil metal anode electrode, and the resultant solid-state Li|PAN-LFP cell exhibits limited polarization and outstanding interfacial stability during long term cycling. That is, the Li|PAN-LFP cell presents a specific capacity of 160.8 mAh∙g⁻¹ at 0.1C, and 81% of the initial capacity is maintained after 500 cycles at 0.2C. The solid-state Li|PAN-LFP cell also exhibits excellent resilience in destructive tests such as cell bending and cutting.     

Cathode materials for lithium ion batteries prepared by sol-gel methods

Improving the preparation technology and electrochemical performance of cathode materials for lithium ion batteries is a current major focus of research and development in the areas of materials, power sources and chemistry. Sol-gel methods are promising candidates to prepare cathode materials owing to their evident advantages over traditional methods. In this paper, the latest progress on the preparation of cathode materials such as lithium cobalt oxides, lithium nickel oxides, lithium manganese oxides, vanadium oxides and other compounds by sol-gel methods is reviewed, and further directions are pointed out. The prepared products provide better electrochemical performance, including reversible capacity, cycling behavior and rate capability in comparison with those from traditional solid-state reactions. The main reasons are due to the following several factors: homogeneous mixing at the atomic or molecular level, lower synthesis temperature, shorter heating time, better crystallinity, uniform particle distribution and smaller particle size at the nanometer level. As a result, the structural stability of the cathode materials and lithium intercalation and deintercalation behavior are much improved. These methods can also be used to prepare novel types of cathode materials such as nanowires of LiCoO₂ and nanotubes of V₂O₅, which cannot be easily obtained by traditional methods. With further development and application of sol-gel methods, better and new cathode materials will become available and the advance of lithium ion batteries will be greatly promoted.     

Zr~(4+)离子掺杂对LiFePO_4结构及电化学性能的影响

应用固相反应法于惰性气氛下合成掺Zr的L iFePO4正极材料.考察Zr4+掺杂浓度对于目标化合物结构及其电化学性能的影响.XRD,交流阻抗和恒流充放电测试等实验表明,少量的Zr4+掺杂并未影响目标材料产物的结构,反而有利于降低L iFePO4电荷转移反应的阻抗,从而有利于克服该电极过程中的动力学限制.该正极材料表现出优良的倍率放电性能,在0.1C倍率下,L i0.99Zr0.01FePO4的首次放电比容量达135.6mAh.g-1.30次循环后,容量衰减仅3.8%.     

A comparative study of overdischarge behaviors of cathode materials for lithium-ion batteries

The overdischarge behaviors of LiFePO₄, LiNiO₂, and LiMn₂O₄ are thoroughly studied in different overlithiation voltage limitations. The results showed that LiFePO₄ and LiMn₂O₄ cathode materials show high structure stability under the overdischarge process to 1.0 V. The microstructure of LiNiO₂ is vulnerable to breakdown under the same testing condition. Fe-based olivine and Mn-based spinel cathode materials show better cyclic calendar life than that of Ni-based layered material. When an extreme overdischarge parameter (down to 0.0 V) is applied, all three samples experience an electrochemically driven irreversible solid-state amorphization process. Due to this overlithiation reaction, the host structure is totally destroyed. Therefore, it is harmful to experience deep overdischarge behaviors for most cathode materials.     

锂离子电池阴极材料LiMn2－xZrxO4的性能表征

采用高温固相法合成了掺杂改性的尖晶石型LiMn2－xZrxO4 (x= 0, 0.01, 0.02, 0.04, 0.06, 0.08, 0.10)作为锂离子电池阴极材料.通过X射线衍射和环境扫描电镜对材料的晶体结构和形貌进行了表征.从材料的晶体结构、恒流充放电测试和循环性能等方面分析了掺杂元素Zr在改善材料性能中的作用.实验表明,当Zr的掺杂量在x ≤ 0.06时,材料在保持较高容量的同时,循环性能得到了明显改善.其中LiMn1.98Zr0.02O4的性能最佳,50次循环后容量仍在113.8 mA•h•g－1以上.     

Synthesis of graphene-supported LiFePO4/C materials via solid-state method using LiFePO4(OH) as precursors

Journal of Solid State Electrochemistry - The solid-state method is a mainly adopted large-scale preparation of LiFePO4 cathode materials for Li-ion batteries but suffers from a challenge of...     

Na3V2(PO4)2O2F的合成及其在钠离子电池中的应用

目前,合成Na₃V₂(PO₄)₂O₂F(NVPF)材料的方法包括高温固相法、水热法、溶剂热法等,这些方法均不利于该材料的大规模工业化生产。本文开发了温和的低温共沉淀法合成NVPF材料,该材料首次放电容量为105.6 mAh·g^-1,首次效率为90.16%。经过简单的热处理过程,可以有效去除由于液相合成带来的结晶水以及吸附在材料表面的羟基,同时还可以提高材料的结晶度,使得材料的首次放电容量提高到124.3 mAh·g^-1,首次效率提高到96.06%。以热处理后的NVPF材料为正极,商业化硬碳为负极组装的全电池表现出了优异的循环性能和倍率性能,1C下循环1200次后容量保持率仍有94.6%,4C倍率下的放电容量仍有基准倍率(0.33 C)的86%。该方法有助于NVPF材料的大规模工业化生产。     

Application of 7Li NMR to characterize the evolution of intercalated and non-intercalated lithium in LiFePO4-based materials for Li-ion batteries

Different synthesis batches of LiFePO₄/C materials were prepared, and their electrochemical properties as positive cathodes for lithium-ion batteries were evaluated. Using standard solid-state NMR conditions, such as a 7-mm magic-angle-spinning probe performing at low spinning rates, information on both intercalated and non-intercalated (stored on the grain boundaries) lithium was obtained. A sharp signal assigned to non-intercalated lithium could be observed by diluting the active material in silica. Correlations could be, thus, obtained between the amount of each type of lithium and the electrochemical history and state of the material, revealing that the relative amount of surface lithium in a pristine LiFePO₄/C material is rather constant and cannot be used as a criterion for its further specification. However, a drastic increase of this surface lithium was observed in the cathode materials of out-of-order batteries. As the cathode material recovered from the batteries after electrochemical testing was carefully washed before analysis, we can conclude that the non-intercalated lithium is strongly bound to the active material probably inside the so-called solid electrolyte interface layer at the surfaces of LiFePO₄ particles. This work illustrates that solid-state lithium NMR can allow rapid characterization and testing of LiFePO₄/C cathode materials.     

锂硫二次电池正极研究进展

综述了锂硫电池中硫基正极材料的制备方法、结构特征以及电化学性能. 简述了单质硫正极材料, 重点探讨了有机硫化物、碳/硫复合材料、聚合物/硫复合材料的结构设计、材料制备、反应机理以及充放电特性, 并对其中存在的问题进行了分析, 还介绍了硫化锂正极材料. 最后对硫基正极的进一步发展, 以及锂硫电池的商业化应用进行了展望.     

Conjugated polyelectrolytes and neutral polymers with poly(2,7‐carbazole) backbone: Synthesis,characterization, and photovoltaic application

Poly(2,7‐carbazole) neutral polymers (PC‐N, PC‐NOH, and PC‐P) and polyelectrolytes (PC‐NBr and PC‐SO₃Na) with hydrophilic pendant groups of ammonium, phosphonate, and sulfonate were synthesized as interlayers for cathode modifications in bulk‐heterojunction photovoltaic cells (BHJ PVCs). The absorptions of the polymers were determined by the poly(2,7‐carbazole) backbone, showing absorption peaks at ～390 nm for their solutions and films. Because of large intermolecular interactions, excimer emissions with wavelengths higher than 500 nm were found in the photoluminescence spectra of the films of the polymers, which weakened the light emissions of the polymers. PC‐N, PC‐NBr, PC‐NOH, and PC‐P possessed comparable HOMO levels of ?5.23 eV and LUMO levels of ?2.4 eV, but HOMO and LUMO levels of PC‐SO₃Na were up‐lying to ?4.91 and ?2.12 eV, respectively. PC‐N, PC‐NBr, PC‐NOH, and PC‐P were selected to construct thin interlayers in BHJ PVCs with PFO‐DBT35:PCBM = 1:4 as the active layer. Compared with traditional Al cathode, bilayer cathodes with the interlayers showed improvements of open‐circuit voltages and short‐circuit currents of the PVCs. PC‐NOH was the best for the photovoltaic performances and over 20% increase of power conversion efficiency (PCE) was achieved. The bilayer cathodes would have great potential to further elevate PCE of BHJ PVCs with other active layer materials. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

层状嵌锂多元过渡金属氧化物的研究

综述了近几年来锂离子电池正极材料层状多元过渡金属氧化物的研究进展,重点讨论了具有协同作用的Ni、Co、Mn三元复合型层状正极材料LiCoxMnyNi1-x-yO2 (0相似文献   

Electrochemical and structural study of LiCoPO<Subscript>4</Subscript>-based electrodes

LiCoPO₄ samples were synthesized by two different techniques (high-temperature solid-state reaction and lower-temperature synthesis using NH₄CoPO₄·H₂O as precursor) and tested as cathode materials for 5-V lithium batteries. An irreversible lithium deinsertion was observed for the high-temperature sample. In contrast, the application of lower-temperature synthesis led to a significant improvement of the lithium storage reversibility. Different delithiation mechanisms in LiCoPO₄ were found for the samples obtained by different synthetic techniques. The nature of capacity fading during cycling of the cells is discussed.     

室温离子液体电解质与锂离子电池正极材料的相容性

室温离子液体作为新一代软功能介质材料,其电化学性质正在引起人们的广泛关注。本文综述了室温离子液体电解质在用于锂离子电池时与正极材料相容性的研究状况,总结了不同室温离子液体电解质与锂离子电池正极材料相容性的基本规律,从正极材料和室温离子液体两个方面探讨了改善室温离子液体/正极材料相容性的基本途径。     

复合掺杂改性的尖晶石LiMn1.98Cr0.02O4-yCly的研究

采用改进的高温固相法合成了阴阳离子复合掺杂改性的锂离子电池尖晶石结构正极材料LiMn1.98Cr0.02O4-yCly(y=0, 0.01, 0.02, 0.03, 0.04, 0.05, 0.10). 采用X射线衍射手段对材料的晶体结构进行了表征. 从材料的晶体结构、充放电容量、循环性能和倍率放电特性等方面分析了复合掺杂在稳定晶体结构和改善材料电化学性能方面的作用. 实验结果表明, 由于复合掺杂的综合作用, 改性后的材料既保持了高的初始容量, 又具有优良的循环性能, 倍率放电性能也得到了有效的改善. 其中LiMn1.98Cr0.02O3.96Cl0.04的综合性能最优, 初始放电比容量达到127 mA·h/g以上, 循环50次后仍有110 mA·h/g的放电比容量.