静电纺丝法制备TMO/C复合纳米纤维在锂离子电池负极材料中的应用进展

过渡金属氧化物(TMO)因其极高的理论比容量被认为是代替石墨成为锂离子电池负极材料的最佳选择之一,但是在充放电过程中的过度体积膨胀以及较差的导电性能限制了其进一步发展.将TMO材料与碳材料复合,既能满足储锂容量需求,又能避免充放电过程中过度体积膨胀.通过对近期相关文献的调研,对以静电纺丝技术为基础制备的TMO/C混合材...     

金属有机框架及其衍生金属氧化物在锂和钠离子电池中的应用

高性能锂和钠离子电池是未来便携电子设备、电动汽车和大规模储能电站的重要组成部分,受到了各行业的广泛关注。目前商用的锂离子电池和研发中的钠离子电池都面临着一些技术瓶颈,主要表现为能量密度低、充放电慢等,导致无法满足市场的需求。具有独特结构、高比表面积的金属有机框架及其衍生金属氧化物可作为电化学储能器件新型电极材料,满足高性能锂和钠离子电池的要求。本文综述了近年来金属有机框架及其衍生金属氧化物作为锂和钠离子电池电极材料的研究进展,同时指出了金属有机框架及其衍生金属氧化物在实际应用中的不足及未来可能的一些改进措施。     

锂/钠离子电池锡锑合金负极材料改性的研究进展

锡锑(SnSb)合金材料具有高理论容量、高电导率、低反应电位等优点,是当前研究最为广泛的锂/钠离子电池负极材料之一。然而,SnSb合金负极材料在嵌脱金属离子过程中巨大的体积效应导致电极材料粉化失活,从而导致其循环性能不尽人意。为了解决上述问题,从结构设计、碳复合材料、三元合金等方面介绍近些年的研究进展,分析现有合成策略的设计方法和作用机理,最后提出SnSb合金负极材料在未来研究中的发展方向。     

一种分散在多孔碳上的碳包覆硅负极的制备及应用

硅负极具有高比容量的显著优势,其理论比容量（4 200 mA∙h/g）达到传统石墨负极的10倍以上,被认为是锂离子电池最有潜力的负极之一。然而,硅负极存在导电性较差、充放电过程中体积膨胀巨大等诸多问题,导致其循环性能较差,限制了大规模实际应用。本文提供了一种高性能硅负极的制备方法及应用,通过将硅负极分散在多级孔碳中,连同黏结剂聚丙烯腈涂覆在集流体上,再对极片进行热处理实现聚丙烯腈碳包覆,有效提高电极的整体导电性并能为巨大的体积变化提供空间,从而提升硅负极的大倍率性能和循环稳定性。     

生物质衍生碳基材料在钠离子电池负极中的应用

近年来,随着可再生能源的大规模应用,开发安全可靠的储能设备对于解决可再生能源的间歇性、不稳定性等问题,实现能源的持续性输出具有重要意义。锂离子电池作为重要的储能设备已成功应用于多个领域,然而,锂资源储量有限、分布不均匀且成本较高,难以满足未来的应用需求。钠离子电池再次进入研究人员的视野,钠离子电池的储能机理与锂离子电池相似,钠与锂位于同一主族,除物理化学性质与锂相似之外,在储量和成本上同样具有较大优势。开发高容量、优异倍率性能和长循环寿命的负极材料是钠离子电池实现产业化的关键。以资源丰富、成本低廉且可再生的生物质合成的碳基负极材料得到广泛研究,其优良的储钠性能已得到证实,有望成为最具潜力的新型低成本高性能钠离子电池负极材料。本文首先介绍了生物质衍生碳基材料主要来源于植物器官、秸秆和废弃生物质,其次阐述了热解法、化学活化法和模板法等制备生物质衍生碳基负极材料的方法,探讨了不同结构的生物质衍生碳基材料的储钠性能,分析了生物质衍生碳基材料的储钠机制,并展望了生物质衍生碳基负极材料未来的研究方向。     

用于钠离子电池的生物质衍生硬碳材料研究进展

钠离子电池(SIB)凭借其储量丰富、低成本的特点已经开始大规模应用,而硬碳材料凭借其理论容量高、循环倍率性能好、结构稳定等特点已经成为钠离子电池主要的负极材料。近年来,以不同生物质作为前驱体合成高性能硬碳材料是储能领域研究的一大热点。本文综述了近年来用于钠离子电池的生物质衍生硬碳材料的研究进展,对生物质碳材料的结构、合成方法进行了归纳,并且对于生物质碳材料的掺杂改性方法进行了总结,最后对生物质碳材料的前景进行了展望。     

生物高分子在锂离子电池硅负极中的研究进展

硅因其超高的理论比容量,有望成为下一代高性能锂离子电池的负极材料.硅在充放电过程中的剧烈体积膨胀会引起颗粒粉化、SEI膜过量生长以及活性物质失去电接触等问题,最终导致容量快速衰减.开发新型硅负极黏结剂和硅碳复合是提升硅负极性能的重要策略.生物高分子材料成本低、环境友好且富含有机官能团,非常适合用来开发低成本、高性能硅负极黏结剂,也适合作为碳前体合成硅碳复合材料.本文综述了近年来基于生物高分子的硅负极黏结剂和以生物高分子为碳前体的硅碳复合材料的研究进展.本文重点介绍了基于海藻酸钠、壳聚糖、淀粉的硅负极黏结剂,总结出生物高分子基黏结剂的主要改性方法有接枝特殊官能团、与其他聚合物共混或交联.基于这些改性方法,可分别提升黏结剂的黏附性、导电子或离子能力以及实现3D网络结构的构建.本文重点归纳了以纤维素、壳聚糖、淀粉、木质素为碳前体的硅碳复合材料,分别介绍了这些复合材料的性质、结构特点,及其对电化学性能的影响.基于以上分析,本文也指出了当前基于生物高分子的硅负极黏结剂和以生物高分子为碳前体的硅碳复合材料的不足,为其下一步发展指明了方向.     

碳还原法制备棒状硅基材料及其在锂浆料电池中的应用北大核心CSCD

以聚环氧乙烷-聚环氧丙烷-聚环氧乙烷三嵌段共聚物(P123)为结构导向剂,正硅酸乙酯(TEOS)为硅源,柠檬酸为碳源,采用水热法得到凝胶状二氧化硅/碳前驱体,采用旋转蒸发方式去除溶剂,通过高温热处理,得到棒状硅氧基碳负极活性材料,提高浆料体系无紧密束缚环境下硅碳材料的性能。借助X射线衍射(XRD)仪、无机元素分析(EA)仪、比表面积及孔隙度分析仪和扫描电子显微镜(SEM)对棒状硅基材料进行结构和形貌表征。结果表明,合成的棒状硅基材料首尾相连,形成莲藕链束,长度约为1~3μm,直径约为200 nm,孔径为6.9 nm,比表面积为282 m^(2)/g。与管长>5μm,比表面积900 m^(2)/g,直径1~2 nm的单壁碳纳米管导电剂在电解液体系中形成长程、短程互补的多级网络,加上大量介孔的存在,有利于保持浆料悬浮稳定性。用世伟洛克电池进行电化学性能测试,电化学测试结果表明首次放电比容量为1300 mAh/g,充电比容量为726 mAh/g,首效为55.8%,在0.05 C下,循环50次充电比容量从726 mAh/g变为557 mAh/g,比容量保持率为76.7%。本工作在用P123为结构导向剂制备二氧化硅的过程中,引入碳源,得到同时具有碳包覆和碳还原二氧化硅的硅基材料,避免使用镁热还原二氧化硅,再碳包覆带来的复杂工艺流程。     

分级多孔纳米碳球的制备及其在锂硫电池中的应用

以戊二醛（GA）与3-氨丙基三乙氧基硅烷（KH-550）为原料,通过醛胺缩合反应、高温煅烧以及碱刻蚀,制备了分级多孔纳米碳球（HPCN）。扫描电子显微镜（SEM）测试表明,制备的HPCN为平均粒径85.3 nm的单分散纳米球。将HPCN与单质S混合,通过熔融-扩散法制备HPCN/S正极材料,组装成锂硫（Li-S）电池后进行电化学测试。测试结果表明,HPCN/S具有优良的电化学性能,使用铝箔集流体时,在0.2 C循环100圈后放电比容量为472.1 mA∙h/g;采用碳纸替代铝箔集流体制备的HPCN/S-CP正极,显示出更加优异的循环稳定性与倍率性能,在0.2 C循环100圈后放电比容量为636.1 mA∙h/g,在1.0 C与2.0 C下的倍率比容量分别为702.7 mA∙h/g、249.4 mA∙h/g。     

锂离子电池硅基负极黏结剂研究进展

硅在自然界中储量丰富,其理论比容量高达4 200 mA∙h/g,已成为高能量密度锂离子电池负极材料的研究热点。但是Si作为负极材料也存在许多不足,最大的问题是电池充放电过程中,硅体积膨胀（高达300%）,导致Si基负极材料粉化脱落、电池容量迅速衰减,其循环性能尚难以满足实际需求。通过研究开发硅基负极专用黏结剂材料,可以有效抑制循环过程中硅的体积变化,维持硅负极结构稳定,提升电池循环性能。本文综述了近年来硅基负极黏结剂材料的研究进展,主要从合成高分子聚合物黏结剂、天然高分子聚合物黏结剂、导电高分子聚合物黏结剂三个方面进行详细归纳总结,并介绍了本课题组在硅基负极黏结剂方面的部分研究成果,期望能为将来的硅基负极专用黏结剂的研究和应用提供一些思路。     

Heterostructural composite of few-layered MoS2/hexagonal MoO2 particles/graphene as anode material for highly reversible lithium/sodium storage

The heterostructural construction of metal disulfide/oxide is essential in the electrochemical performance as anode material for lithium- and sodium-ion batteries (LIBs and SIBs). In this work, an integrated composite of molybdenum disulfide (MoS₂) and hexagonal molybdenum dioxide (MoO₂) together enwrapped in reduced graphene oxide (rGO) is synthesized under hydrothermal condition. In the pelletizing MoS₂-MoO₂/rGO composite, rGO as substrate effectively prevents the restacking and pulverization of MoS₂-MoO₂ during a long cycling process. Meanwhile, the synergistic effect among the MoS₂, MoO₂, and rGO components are responsible for abundant active sites and shorten ionic transport channels. When evaluating as anode material for LIB, MoS₂-MoO₂/rGO sample presents excellent cyclic performance and still delivers a high capacity of 1062.3 mA h g⁻¹ after 120 cycles at 0.2 A g⁻¹; evaluating in a SIB at 0.04 A g⁻¹, it presents excellent cyclic performance and delivers 430 mA h g⁻¹ at the 80th cycle. The heterostructural composite MoS₂-MoO₂/rGO is one of the candidate anode materials for high-performance LIB and SIB.     

Patent application of silicon-based anode for lithium-ion batteries

本文通过对锂离子电池硅基负极技术领域的专利申请态势进行分析,揭示该技术领域当前的专利活动特点,为我国在该领域的科技创新和产业化提供参考。本文从国际专利申请数量年度分布、主要竞争国家/地区、专利技术来源国和目标国、主要专利申请人等方面,对硅基负极技术领域的专利申请态势进行分析,在此基础上,对世界范围内的主要竞争国家及重要申请人的专利申请特点进行重点分析。分析结果表明,硅基负极专利申请主要集中在中国、美国、日本和韩国。国外申请人注重同时在上述四国进行专利布局,并且已经在我国进行大量专利布局,而我国申请人主要在国内进行专利布局,在国外申请较少。最后,就我国未来的锂离子电池硅基负极技术的研发和专利申请与保护工作提出一些建议。     

A facile control in free-carbon domain with divinylbenzene for the high-rate-performing Sb/SiOC composite anode material in sodium-ion batteries

Sodium-ion batteries (SIBs) are not only cheaper to produce than lithium-ion batteries, but the reserves of sodium in the world are also more uniform and abundant. Thus, efforts are being made to utilize sodium-ion batteries as next-generation large-capacity energy-storage devices. Sb-based anode materials have emerged as a popular alloying material for SIB owing to their high theoretical capacity. However, Sb exhibits the problem of capacity fading owing to excessive volume expansion (approximately 390%). SiOC is a buffer material that has been investigated in terms of its ability to overcome these disadvantages; however, SiOC has the disadvantage of containing a fixed and limited free-carbon domain. Here, high free-carbon contained in Sb/SiOC composites (HFC-Sb/SiOC) was easily synthesized by the heat treatment of divinylbenzene (DVB), a liquid carbon source, with silicone oil and Sb acetate. Sb nanoparticles were uniformly embedded in DVB-modified SiOC with increased free-carbon domains. This composite material showed cycling stability (344.5 mAh g⁻¹ after the 150 cycles at 0.2 C) and outstanding rate properties (197.5 mAh g⁻¹ at 5 C) as the SIB anode. The enhanced electrochemical performance is result from the increased free-carbon domains in the SiOC matrix caused by the addition of DVB, which makes the characteristics of the SiOC material softer and more elastic, suppressing volume changes and enhancing the electrical conductivity.     

Rb掺杂Li4Ti5O12作为锂离子电池负极材料的合成及电化学性能

合成了不同Rb掺杂量的钛酸锂（Li_4-xRb_xTi₅O₁₂; x = 0.010, 0.015, 0.020）作为锂离子电池的负极材料。测试结果显示,Rb离子掺杂有效增强了钛酸锂的电子电导率。相同的测试条件下,相比于未掺杂样品和高Rb含量掺杂样品（x = 0.015, 0.020）,适量的Rb掺杂钛酸锂（Li_3.99Rb_0.01Ti₅O₁₂; x = 0.010）表现出最优的电化学性能。Li_3.99Rb_0.01Ti₅O₁₂材料表现出161.2 mA∙h/g的初始容量,且在1 C下经过1000次循环后容量保持率可达90.9%。此外,全电池Li_3.99Rb_0.01Ti₅O₁₂ // LiFePO₄在0.5 C条件下首次放电容量为144 mA∙h/g,经过150次循环后,容量保持率为78.8%。     

Carbon nanofiber activated by molybdenum disulfide as an effective binder-free composite anode for highly reversible lithium storage

Carbon nanofiber film (CNF) as anode material for lithium-ion batteries (LIBs) draws attention for its excellent cyclic stability, but its practical application is limited due to low specific capacity. Considering the advantages of pure CNF and MoS₂, a flexible film which CNF covered by MoS₂ (MoS₂/CNF) is successfully produced and evaluated as a binder-free electrode for LIBs without mixing with carbon black and polymer binder. MoS₂ nanoflakes (8.91 wt% of the composite sample) covering on CNF (MoS₂/CNF-B sample) plays the key role in activating the electrochemical properties of CNF, but dense MoS₂ nanoflakes (39.4 wt%) on CNF (MoS₂/CNF-A) seriously limit the electrochemical properties of CNF. At 0.1 and 1.0 A g⁻¹, MoS₂/CNF-B sample delivers 967.1 and 605.7 mA h g⁻¹, the capacities are almost twice as much as those of pure CNF. The initial columbic efficiency of MoS₂/CNF-B sample of 76.4% is much higher than that of pure CNF sample of 62.1%. Moreover, MoS₂/CNF-B sample presents no capacity decay till 100 cycles, and the cycled electrode at the 100th cycle still maintains a stable composite structure of MoS₂ nanoflakes covering on CNF.     

3D-functionalized carbon nanotube microsphere networks modified by 1-aminopyrene promote silicon anode with an enhanced cyclic performance for Li-ion batteries

Although silicon has higher theoretical specific capacity to meet the demand for higher energy density, its large volume expansion and low conductivity make the practical application of silicon anode difficult in the field of lithium-ion batteries. In this work, Si@(AP-AOCNTs) composites with uniform conductive network and pore structure are prepared by spray drying method. In the composite microspheres, silicon particles are embedded into the 3D interwoven network of 1-aminopyrene modified oxidized carbon nanotubes, which can not only buffer the volume expansion of silicon, but also ensure the effective transport of electrons and ions. This is demonstrated by the remarkable cycle life, and the electrode still has a reversible specific capacity of 939.3mAh/g after 975 cycles at 0.5A/g. Moreover, 97.3% of the initial capacity (at 0.5A/g) is still retained after the rate cycling, when the current density returns to 0.5A/g.     

Na3V2(PO4)3@NC composite derived from polyaniline as cathode material for high-rate and ultralong-life sodium-ion batteries

Polyaniline-derived N-doped carbon-composited Na₃V₂(PO₄)₃ (NVP@NC) are synthesized by a rheological phase reaction followed by calcination. The NVP@NC composite displays improved cycling and rate properties. Its discharge capacity remains 118.7 mAh g⁻¹ at the 400th cycle at 0.3 C. It also obtains invertible capacities of 93.7 and 91.1 mAh g⁻¹ at 5 and 10 C after 1000 cycles, with capacity retention rates of 92.7% and 98.4%, respectively. These enhanced results due to the N-doped carbon layer (NC), which restrains the expansion and deformation of the crystal structure, reduce the transport length of sodium ion and electrons and improves the electroconductibility of NVP.