锂离子电池柔性碳布负极材料的储锂性能研究

将柔性碳布用于锂离子电池负极材料,用循环伏安法及交流阻抗研究了电池电极材料的电化学性能,用充放电实验研究了电池的循环性能和倍率性能。结果表明,锂离子电池负极采用柔性碳布,具有高的锂储存容量,第一次放电比容量为157.48mAh/g,并且在随后各次的容量损失很小,电池循环趋于稳定。     

硬碳材料作为室温钠离子电池负极材料研究进展

室温钠离子电池以潜在的高性价比优势在大规模储能领域具有广阔发展空间。硬碳材料因其丰富的结构和优良电化学性能被认为是最有潜力的钠离子电池负极材料。但硬碳材料的储钠机理仍存在争论且电化学性能仍需进一步提高。本文在硬碳材料和其储钠机理两个方面综述了近年来硬碳材料储钠的研究进展,并对其发展前景进行了展望。     

高性能钠离子电池负极材料的研究进展

负极材料的研究是钠离子电池实现商业化生产的关键要素之一，近年来已经取得了突破性进展。但是较大半径的钠离子在嵌/脱过程中对负极材料结构的影响非常大，进而导致可逆容量迅速降低。本文系统综述了钠离子电池负极材料的最新研究成果，阐述了碳基材料、钛基化合物、合金材料、金属化合物和有机化合物5类负极材料的制备工艺，并分析了这些材料的性能特点：碳基材料的研发技术成熟，但比容量和倍率性能有待提高；钛基化合物的结构性能良好，倍率性能出色，但存在比容量较低的缺点；合金材料和金属化合物都具有较高的理论比容量，但循环性能较差；有机化合物的研发尚处于起步阶段，有待深入研究。基于现有的研究基础，总结了材料的改性方法和取得的效果，并展望了钠离子电池负极材料的研究方向，分析指出表面碳包覆可以提升材料的电子传导性，纳米结构可以缩短钠离子的传输途径，多孔形貌有利于电解质对材料的浸润，而元素掺杂可以提升材料的反应活性，最终获得高性能钠离子电池负极材料。     

硅负极表面构建人造SEI膜及软包电池应用研究

硅基材料在脱嵌锂过程产生较大的体积变化,造成SEI膜的破损和不断重构,限制了其大规模应用。本文将聚丙烯酸和聚环氧乙烷通过层层组装技术,包覆在硅负极表面,形成人造SEI膜,通过红外、SEM等分析了构建人造SEI膜后硅负极材料结构及表面变化情况。并将该硅负极材料组装成软包全电池,评估了25℃和45℃循环测试、EIS等性能。结果表明通过构建人造SEI膜可以明显提升硅负极电池循环容量保持率和减低电芯厚度,25℃循环600T,容量保持率由87.9%提高到92.6%,电芯的膨胀率为10.7%下降到9.4%。45℃循环500T,容量保持率由83.5%提高到85.9%,电芯的膨胀率为12.6%下降到10.9%。循环后通过截面SEM表征显示,构建PAA/PEO人造SEI膜后的硅颗粒循环后总SEI膜厚度由0.35μm降低到0.2μm,具有很好的应用前景。     

花状SnSe0.5S0.5@N-C复合材料的制备及其在钠离子电池中的应用

为了设计具有高容量和循环稳定性的钠离子电池负极材料,合成了有序花状SnSe,在其表面进行氮碳掺杂,并进一步硫化,得到有序花状SnSe0.5S0.5@N-C复合材料.采用SEM、TEM、XRD、XPS对复合材料的结构和形貌进行了表征,并将其作为钠离子电池负极进行了性能测试.结果表明,当SnSe0.5S0.5@N-C作为钠离子电池负极时,表现出较高的可逆容量和优异的循环性能.在0.2 A/g电流密度下,复合材料在循环100圈后的可逆比容量仍可高达430.7 mA·h/g.     

锂离子软包倍率电芯短路漏液改善研究

锂离子软包倍率电芯短路测试时通常可以满足不着火不爆炸不冒烟的要求,但一般都会漏液。针对软包倍率电芯在短路测试时常见的漏液问题,采用超薄的负极耳设计,负极耳可以在短路的瞬间熔断从而阻止短路的进一步进行,最终电芯短路后不漏液,解决了软包倍率电芯短路漏液带来的安全问题。和传统的加PTC的解决短路漏液方案对比,采用超薄负极耳方案可以电芯降低内阻,节省空间和节约成本,同时电芯保持高倍率放电及循环性能。     

钠离子电池硬炭负极研究进展

无定形结构的硬炭以其不同于石墨有序结构的结构优势，以及低成本和原材料来源广，被认为是钠离子电池(SIBs)最有前途的碳基负极材料，其复杂的微观结构与钠储存有着密切的关系。在硬炭微观结构中缺陷，层间和纳米孔隙是硬炭储钠的三个关键特征结构，深入研究这些特征结构有利于实现高容量钠离子电池碳基负极的有效构造，并有利于推进钠离子电池产业化进程。最后对高性能钠离子电池负极的结构设计进行了展望。     

过期藻酸双酯钠药片的电化学储钠/锂性能

为了开发过期藻酸双酯钠药片中的非医疗价值,首先采用扫描电子显微镜、能量色散X射线光谱仪及Fourier红外光谱仪研究了其微观形貌、元素组成及结构,然后进一步利用恒流充/放电与循环伏安技术研究了其电化学储钠/锂性能。结果表明:虽然藻酸双酯钠药片已经过期3年,但其主要成分和结构并未发生明显变化;在50 mA/g循环充/放电时,藻酸双酯钠负极材料在钠离子电池和锂离子电池中的首次放电比容量分别为126.6和282.3 mA?h/g,可逆放电比容量分别为95.7和158.5 mA?h/g,表现了良好的电化学储钠/锂性能及作为钠/锂离子电池负极活性材料的可行性。     

硬碳材料的功能化设计及其在钠离子电池负极中的应用

硬碳拥有容量高、工作电位低、成本低等优势,在钠离子电池负极中展现出潜在的应用前景。其最重要的特点是拥有丰富的微晶结构,这对钠离子的吸附及嵌入/脱出过程十分有益,使硬碳展现出优益的储钠性能。在实际应用中,硬碳存在首效低、稳定性不足以及倍率性能较差等问题,功能化设计是针对性改善硬碳上述缺陷的有效策略。结合目前硬碳功能化改性方面的研究工作,系统介绍了近年来关于硬碳负极在功能化设计方面的典型策略及最新研究进展,并探讨了功能化设计的优势与不足,为指导未来钠离子电池硬碳负极的商业化应用提供理论基础和技术支撑。     

石墨负极的压实密度对软包锂离子电池性能的影响

石墨负极的压实密度是影响锂离子电池循环性能和倍率放电性能的主要因素之一。通过研究3种不同压实密度的石墨负极材料的电化学性能,发现随着压实密度的增大,负极极片的吸液时间逐渐延长,电池的内阻也在不断地增加。当负极压实密度为1.7 g/cm³时,锂离子电池的循环性能和倍率性能均为最佳。电池在0.5 C下放电循环500次后的容量保持率为86.8%,3.0 C倍率的放电容量为0.2 C放电容量的95.1%。     

绝热加速量热仪在锂/钠离子电池研究中应用

电池热失控主要由于外部高温环境等因素，使得电池内部发生一系列的化学反应，导致电池内部的温度上升。电极材料、电解液以及它们之间的匹配程度都将影响电池的安全性能。绝热加速量热仪（ARC）由于其能研究绝热环境下的自加热情况且灵敏度高等优点成为电池安全性研究的方式之一。通过ARC测试，可以得到自放热速率和温度的变化关系，推动锂/钠离子电池动力学研究、热失控原因分析以及电极材料、电解液热安全性能评估的研究。本文回顾了近二十年来绝热加速量热仪在锂/钠离子电池安全性方面的研究，比较了不同的电极材料、电解液以及电池的热行为，筛选出安全性更高的电池材料与电解液体系，为今后的锂/钠离子电池的设计和研究提供有效的理论数据与参考。     

Scalable synthesis of Na3V2(PO4)3/C with high safety and ultrahigh-rate performance for sodium-ion batteries

NASICON-type Na₃V₂(PO₄)₃ is a promising electrode material for developing advanced sodium-ion batteries. Preparing Na₃V₂(PO₄)₃ with good performance by a cost-effective and large-scale method is significant for industrial applications. In this work, a porous Na₃V₂(PO₄)₃/C cathode material with excellent electrochemical performance is successfully prepared by an agar-gel combined with freeze-drying method. The Na₃V₂(PO₄)₃/C cathode displayed specific capacities of 113.4 mAh·g^-1, 107.0 mAh·g^-1 and 87.1 mAh·g^-1 at 0.1 C, 1 C and 10 C, respectively. For the first time, the 500-mAh soft-packed symmetrical sodium-ion batteries based on Na₃V₂(PO₄)₃/C electrodes are successfully fabricated. The 500-mAh symmetrical batteries exhibit outstanding low temperature performance with a capacity retention of 83% at 0 ℃ owing to the rapid sodium ion migration ability and structural stability of Na₃V₂(PO₄)₃/C. Moreover, the thermal runaway features are revealed by accelerating rate calorimetry (ARC) test for the first time. Thermal stability and safety of the symmetrical batteries are demonstrated to be better than lithium-ion batteries and some reported sodium-ion batteries. Our work makes it clear that the soft-packed symmetrical sodium ion batteries based on Na₃V₂(PO₄)₃/C have a prospect of practical application in high safety requirement fields.     

改善锂硫电池易燃特性的功能性隔膜研究进展

锂硫电池具有较高的能量密度,可在单兵电源、无人机和乘用车领域应用. 锂硫电池以金属锂作为负极,使用时存在安全隐患. 由于锂金属表面的不均匀性,循环过程容易生成锂枝晶,使电池内部发生短路,起火燃烧. 锂硫电池的能量密度约为普通电池的3~5倍,在充放电过程中发热严重,电池本身过热容易引发电池热失控,造成起火甚至爆炸. 使用功能性隔膜可以抑制电池内部短路和热失控的发生,提升锂硫电池的安全性能,可一定程度上削弱循环过程中的飞梭效应. 本文综述了锂硫电池功能性隔膜改性工作的最新进展和未来的发展趋势.     

钠离子电池中关键材料及技术的发展与前景

钠离子电池因其储量大、成本低和高安全性等优势,成为锂离子电池的有效替代品,可在一定程度上缓解锂资源短缺引发的储能电池发展受限问题。本文对钠离子电池发展现状、面临的挑战以及未来发展趋势进行梳理分析,并精选钠离子电池最新前沿综述,包括正极材料、负极材料和先进表征技术等,探讨当前钠离子电池的研究热点,为新能源材料领域技术研究提供参考。     

钠离子电池负极材料的储钠机制及性能研究进展

绿色能源的应用,促使着电化学储能与转换技术的飞速发展。锂离子电池作为储能领域最成功的二次离子电池之一,已被应用于各种电子产品中,但是由于锂资源短缺造成锂离子电池的成本增加,限制了其在大规模储能设备领域的应用。因此,寻找价格低廉、性能优异的二次离子电池是当下的研究热门之一。钠离子电池不仅拥有和锂离子电池相似的工作原理,而且还具有成本低、资源丰度大和可逆容量高的特点,有望成功地代替锂离子电池而应用于商业化生产。本工作主要综述了钠离子电池负极材料的性能研究进展,首先根据钠离子在负极材料存储方式不同,分析归纳了负极材料的插层反应、合金化反应和转换反应三种储钠机制,然后介绍了负极材料的结构修改、元素掺杂和材料复合三种改性方式,随后重点介绍了碳基材料、钛基材料、合金类材料、转换类材料和有机材料等几种关键的钠离子电池负极材料的电化学性能和所面临的问题,最后,以实际生产和工业应用为基础,展望了钠离子电池负极材料的研究方向。     

Theoretical analysis of lithium‐ion battery failure characteristics under different states of charge

Lithium‐ion batteries (LIBs) are extensively applied in various portable electronic equipment because of their high energy density power. However, accidents related to LIBs frequently occur. This study focuses on failure results, characteristics, and phenomena. Lithium‐ion batteries under different states of charge (SOCs) (0%, 30%, 50%, 80%, 100%, and 120%) at high temperatures have been investigated with the thermal abuse test. During the experiments, several typical failure processes were captured. According to the phenomena, 2 failure modes (smoke and jet fire) and 3 stages (primary reaction, tempestuous reaction in the middle time period, and extinguishing reaction in the final stage) were observed. A substantial amount of gas was vented, and jet fire was detected in the middle period. Only gas vented when the SOC was lower than 50%, whereas vented gas and jet fire were detected simultaneously when the SOC exceeded 50%. The results indicated combustible behaviors and exothermic reactions related to the SOC. An increase in the SOC caused a decrease in the thermal runaway initial temperature and the maximum increase in temperature. A higher SOC determined intense chemical reactions in the cell at higher temperatures, which caused a significant amount of materials to spew out of the batteries as well as additional mass loss. Relationships between failure characteristics and internal reactions were analyzed. The SOC should be lower than 50% in transportation or storage. The intercalated lithium capacities were the main reason for the series of domino reactions, which caused runaway in the terminal. These studies can serve as a reference for safety applications, transportation, and loss prevention in LIBs.     

钴酸锂电池烤箱热滥用模拟及热行为分析

建立钴酸锂电池烤箱热滥用的热模型,并对不同烤箱温度下的热滥用进行数值模拟。比较分析电芯不同区域的热滥用反应及热行为发现,高温下电池电芯发生热失控的主要热量来自于正电极与电解液的反应,隔离膜区域的热生成量最少。考察不同散热条件和烤箱温度对电芯热行为的影响发现,散热条件和环境温度是影响电芯热行为的关键因素,发生热失控的临界温度随着散热条件的变好而升高,使得电池不发生热失控的临界散热系数随着烤箱温度的升高而增大。     

MOF-derived hollow Co(Ni)Se2/N-doped carbon composite material for preparation of sodium ion battery anode

Hollow and porous three-dimensional Co(Ni)Se₂/N-doped carbon composite particles prepared by a simple process using metal organic framework (MOF) precursors as the template are used as a high-efficiency anode material for sodium ion batteries. The composite material having a regular rhombohedral dodecahedral structure contains the N-doped porous carbon shell and the nano-metal selenide (CoSe₂ and NiSe₂) embedded in the carbon shell. Moreover, the metal selenide has a high capacity density, and the N-doped porous carbon structure can enhance the electrical conductivity and structural stability of the material to suppress volume expansion. Their effective synergistic combination shows excellent electrochemical performance. As the anode of the sodium ion battery, Co(Ni)Se₂@NCC exhibits a very high specific capacity of up to 735.2 mA h g⁻¹ after 100 cycles and superior rate performance. In addition to these, excellent kinetic performance and cycle stability and coulombic efficiency are sufficient to prove that this material has broad prospects in sodium-ion battery anodes.     

Thermal runaway of valve-regulated lead-acid batteries

Valve-regulated lead-acid (VRLA) batteries that have aged on a float charge at constant voltage occasionally suffer from thermal runaway. Operating conditions for a VRLA battery have been simulated by changing the electrolyte saturation level in the separator and the ambient temperature. The charge current, battery temperature and cell overpressure were measured during current-limited constant-voltage charging. The experiments show that applied voltage, saturation level and ambient temperature are significant variables in the oxygen cycle. However, the saturation level of the electrolyte in the separator pore volume is critical. When it is lower than 80%, thermal runaway occurs readily. Significant corrosion of the positive grid and poor conductivity between the grid and the active mass (AM) is also found in aged VRLA batteries, and many inactive PbSO₄ crystals appear on the negative plates. As a result, both positive and negative plates have a very high resistance, which can accelerate thermal runaway.     

A mini review on cathode materials for sodium-ion batteries

Sodium-ion batteries are becoming potential solutions for replacement of batteries due to the abundance of sodium reserves and high recycling costs of lithium-based batteries. Sodium-based layered oxides are being widely explored as positive electrode material for sodium-ion battery due to their high capacities and high energy densities. However, oxide-based systems do suffer from thermal stability issues and exhibit low power density. On the other hand, polyanionic-based compounds and Prussian blue analogues demonstrate appreciable thermal stabilities and are useful in high power density applications. This article reviews recent trends of these cathode materials.