Research progress of novel binders for silicon-based anode in lithium ion battery

硅基材料由于具有超高的理论比容量,安全的嵌锂工作电位和廉价易得等诸多优点,是下一代高比能量电池体系最理想的负极材料。尽管硅基材料的研究已经进行很长时间,但是硅基材料嵌锂时巨大的体积膨胀,循环性能较差等问题一直难以得到有效解决。开发高性能硅基负极黏结剂是解决硅基材料应用问题的重要途径之一,具有“刚柔并济”结构特性的黏结剂分子能够有效抑制硅基材料结构膨胀粉化,保持电极导电网络的完整性,从而有效提升其循环性能。本文综述了硅基负极黏结剂的特性要求,新型硅基负极黏结剂的研究进展,并对该领域未来潜在的研究方向进行了展望：复合体系聚合物黏结剂的开发;特殊空间构型黏结剂的开发;新型导电黏结剂的开发;自支撑无黏结剂硅基负极的开发。     

高能量锂离子电池硅基负极黏结剂研究进展北大核心CSCD

硅材料具有较高的理论容量,被视为发展高能量锂离子电池的重要材料之一。但是硅在充放电循环中体积变化较大,会导致负极材料粉化,严重影响电池的电化学性能。黏结剂作为电极的重要组成部分,对于稳定负极结构,改善电池性能具有重要作用。总结归纳了合成类聚合物、生物类聚合物等硅基负极黏结剂的研究进展,合成类聚合物主要包括聚丙烯酸类、聚偏二氟乙烯类以及导电类黏结剂,生物类聚合物主要包括羧甲基纤维素类、海藻酸钠类以及其他生物类黏结剂。分析了选择硅基负极黏结剂的条件,包括要有极性官能团、具有一定的弹性和机械强度、化学稳定性高、最好具有一定的导电性等。极性基团可以与硅表面的羟基形成氢键,增强材料之间的黏结性能,为了更好地制约硅的体积膨胀,可以对其进行改性,使其具有一定的弹性和自愈能力;也可以选择一些导电物质,使黏结剂本身具有导电性能,可以提高电极内部导电网络的稳定性并提高活性物质的含量等。本文也为黏结剂的选择和发展提供了思路。     

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.     

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。     

锂电池百篇论文点评(2020.10.01—2020.11.30)

该文是一篇近两个月的锂电池文献评述,以"lithium"和"batter*"为关键词检索了Web of Science从2020年10月1日至2020年11月30日上线的锂电池研究论文,共有2731篇,选择其中100篇加以评论.层状正极材料主要研究了高镍三元材料和富锂相材料中的氧氧化还原机制,掺杂和表面包覆是常用的改性方法.硅基复合负极材料的研究重点包括负极嵌锂的体积膨胀问题以及通过引入新的黏结剂和在材料表面预形成SEI等方法提升材料的循环性能,有关负极的研究工作还包括Ti2Nb10O29负极、还原氧化石墨烯及其复合材料负极、三维碳负极材料等.电解液添加剂的研究包括适用于高电压三元材料、富锂材料、高电压磷酸钴锂材料、锂硫电池和厚电极的功能电解液添加剂.固态电解质的研究对象涵盖硫化物固体电解质、聚合物与硫化物/氧化物固体电解质复合材料、硅掺杂的Li6PS5I和硼酸锂掺杂的Li7La3Zr2O12等.无机电解质和无机/聚合物复合电解质固态电池、锂硫和锂空气电池的论文也有几篇.表征分析偏重于固液界面SEI、金属锂沉积过程、锂在电极中的空间分布he1电池气胀问题等.理论模拟工作涉及SEI形成机制以及厚电极电池的动力学等.     

锂电池百篇论文点评(2022.10.01—2022.11.30)北大核心CSCD

该文是一篇近两个月的锂电池文献评述,以“lithium”和“battery*”为关键词检索了Web of Science从2022年10月1日至2022年11月30日上线的锂电池研究论文,共有3301篇,选择其中100篇加以评论。正极材料的研究主要集中在对高镍三元和尖晶石镍锰酸锂的表面改性和体相掺杂,及其在长循环过程中或高电压下所发生的表面和体相的结构演变。硅基复合负极材料的研究包括材料制备和对电极结构的优化以缓冲体积变化,并重点关注了功能性黏结剂的应用。金属锂负极的研究包含金属锂的表面修饰和无负极金属锂电池。固态电解质的研究主要包括对硫化物固态电解质、氧化物固态电解质、聚合物固态电解质以及复合固态电解质的结构设计以及相关性能研究。其他电解液和添加剂的研究则主要包括不同电解质和溶剂对各类电池材料体系适配的研究,以及对新的功能性添加剂的探索。固态电池方向更多关注正极中离子、电子传输能力的提升。锂硫电池的研究重点是提高硫正极的活性,抑制“穿梭”效应。测试技术涵盖了锂沉积和硅负极演化等方面。电池工艺相关的研究工作侧重于电极极片制作和浆料的特性。     

含硅负极在硫化物全固态电池中的应用

硫化物固态电解质具有超高离子电导率和优良力学性能,是实现全固态电池最有希望的技术路线之一.为进一步提高硫化物全固态电池的能量密度,促进其应用,理论比容量接近石墨10倍(3759 mA·h/g)的硅负极材料具有极佳的应用前景.并且Si负极和硫化物固态电解质结合,可规避Si负极在液态电池中重复生成固态电解质界面层(SEI)的问题,充分发挥Si负极的高容量,同时利用硫化物较好的力学性能缓冲硅负极巨大的体积膨胀,改善固固接触,促进离子扩散,有望实现高能量密度电池的长效循环.虽然含Si负极硫化物全固态电池极具实用前景,但是目前研究尚处于起步阶段,缺少成熟有效的表征手段和对基础科学问题的深入理解,全电池性能较差、容量衰减过快、比能量还有很大提升空间.为加速推进含Si负极硫化物全固态电池的研究进程,本文总结了近年来该领域的相关工作,分类论述了 3种类型的含Si负极硫化物全固态电池(粉饼电池、湿法涂覆电池、薄膜电池),综合分析了影响其性能的关键因素,并阐明通过减小Si的颗粒尺寸、外加应力、设置合适的截止电压、调控硫化物电解质的杨氏模量等手段可以有效优化含Si负极硫化物全固态电池的性能.最后,本文分析了目前该领域面临的问题和挑战,指出未来发展趋势.     

锂电池百篇论文点评(2021.2.1-2021.3.31)

该文是一篇近两个月的锂电池文献评述,以"lithium"和"batter*"为关键词检索了 Web of Science从2021年2月1日至2021年3月31日上线的锂电池研究论文,共有2566篇,选择其中100篇加以评论.本文对层状氧化物正极材料的研究集中在掺杂、包覆、前驱体及合成条件、循环中的结构变化,其中,高镍三元材料是讨论的重点.硅基负极材料方面关注体积膨胀及其带来的后续问题,相关研究内容包括对硅颗粒的包覆、复合硅基负极及其结构调控.金属锂、碳负极和氧化物负极等其他负极也有涉及,其中,对金属锂负极界面的研究和三维结构负极设计是重点.固态电解质的研究主要包括对硫化物固态电解质、氧化物固态电解质、聚合物-氧化物复合固体电解质的合成、掺杂以及相关性能研究.液态电解液方面主要为针对适应高电压三元层状氧化物正极和金属锂负极的电解液及添加剂研究,还有添加剂对正/负极界面层的调控作用和对石墨、硅负极的性能提升.对于固态电池,复合正极制备和设计、活性材料的表面修饰、锂金属/固态电解质界面等都是主要研究内容.其他电池技术偏重于基于催化、高离子/电子导电基体的复合锂硫正极构造以及"穿梭效应"的抑制.表征分析部分涵盖了金属锂沉积,石墨和硅负极的体积膨胀问题,正极的微结构、过渡金属元素溶解和产气以及固态电池中电解质分解、界面接触损失等问题.理论模拟工作涉及固态电池中界面接触损失、锂负极的沉积和剥离、电极界面稳定性.界面主要涉及固态和液态电池中SEI及其可视化表征.     

Research progress on Si/C composites as anode for lithium ion batteries

硅基负极材料具有比容量高、电压平台低、环境友好、资源丰富等优点,有望替代石墨负极应用于下一代高比能锂离子电池。但是硅的导电性较差,且在充放电过程中存在巨大的体积效应,极易导致电极极化、材料粉化、SEI膜重构、库仑效率低和容量持续衰减。硅和碳复合能很好地综合两者的优势,形成结构稳定、循环性好及容量高的负极材料。本文从不同维度的硅（SiNPs、SiNTs/SiNWs、SiNFs、Bulk Si）与碳复合这一角度,综述了硅碳复合材料在结构设计、制备工艺、电化学性能等方面的最新研究进展,并对未来的硅碳复合材料的研究工作进行了展望。     

Advances in tin-based nanoparticles and their nonocomposite anode for lithium ion batteries

锡基负极材料由于具有很高的储锂容量,较低的电压平台和较大的压实密度而得到广泛的研究,是最具应用潜力的下一代锂离子电池负极材料之一.然而,锡基负极材料在充放电过程中巨大的体积效应导致电极材料破碎粉化脱落,严重降低了电池的循环寿命和限制了其商业化应用.超细化和复合化是解决锡金负极材料缺陷的有效途径,本文论述了近年来在锡基负极材料研究方面的热点及最新成果,特别是超细SnO₂纳米颗粒及其与碳纳米管或石墨烯复合负极材料方面的研究进展.     

The progress of novel binder as a non‐ignorable part to improve the performance of Si‐based anodes for Li‐ion batteries

In this review, we highlight recent achievements of polymer binders used for Si‐based anodes in Li‐ion batteries. We classify the polymer binders, depending on their polymer structures and the function on performances of Si‐based anodes, into 3 types: cellulose‐type, conductive‐type and self‐healing‐type binders. The relationship between polymer structures and enhanced electrochemical performances of Si‐based anodes is discussed in details. We investigate how the binders make an extraordinary improvement on the specific capacity, cycling stability and rate performances of Si‐based anodes. The reasons of the noticeable effect on Si‐based anodes especially the controlling of swelling during cycling are also researched. In a word, the main aim of this review is to analyze recent research achievements and propose perspectives of polymer binders used for Si‐based anodes in promising Li‐ion batteries.     

薄膜锂离子电池负极材料的研究进展

全固态薄膜锂离子电池是锂离子电池的最新研究领域,其能量密度高、厚度薄、循环寿命长、可靠度高。薄膜化的负极材料是锂离子电池的重要组成部分,负极薄膜材料制备方法的研究取得了较大的进展,未来研究重点是低成本、低能耗、高综合电化学性能的负极薄膜材料以及可批量生产的薄膜制备技术。对薄膜化的硅负极材料、金属或合金薄膜材料、氧化物薄膜材料和复合薄膜材料近几年来的研究状况进行了综述,并对其发展前景进行了展望。     

Nano- and bulk-silicon-based insertion anodes for lithium-ion secondary cells

The increase in energy density and power density requirements for lithium-ion secondary cells for commercial applications has led to a search for higher capacity electrode materials than those available today. Silicon would seem to be a possible alternative for the graphite or carbon anode because its intercalation capacity is the highest known. However, the large capacity fade observed during initial cycling has prevented the silicon anode from being commercialized. Here we present a review of methodologies adopted for reducing the capacity fade observed in silicon-based anodes, discuss the challenges that remain in using silicon and silicon-based anodes, and propose possible approaches for overcoming them.     

A simple spray assisted method to fabricate high performance layered graphene/silicon hybrid anodes for lithium-ion batteries

Incorporating silicon (Si) in anodes has shown great promise for the development of high capacity Li-ion batteries (LIBs). Moreover, it is a safe and environmentally benign material, and hence suitable for large-scale manufacturing. However, volumetric expansion of Si particles upon lithiation causes irreversible damage to the anode structure and promotes an unstable solid electrolyte interface (SEI), that cause a rapid capacity drop. The architecture of successful Si-based anodes, therefore, needs to cater to the large volumetric expansion such that the high specific capacity of Si can be taken advantage of without having to worry about the detrimental effects of expansion. In this study, we introduce a simple and cost-effective spray-drying method to fabricate a layered (sandwich-like) anode structure using synthesized Si nanoparticles (NPs) and thermally reduced graphene oxide (rGO). The Si NPs are obtained by the magnesiothermic reduction of SiO₂ nanoparticles. Using an original, scalable, and simplistic spraying/drying method, we embedded Si NPs between two coats of strong yet flexible rGO sheets. The sandwich-like structure, which successfully contains the expansion of Si particles, protects the anode from detrimental conditions. With this new and uncomplicated production technique, the rGO-Si-rGO anode after 50 cycles, shows a high specific capacity of 1089 mAhg⁻¹ at 1C with 97% coulombic efficiency and a stable cycling performance at current densities up to 5C.     

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.     

Electrochemical properties of carbon-coated Si/B composite anode for lithium ion batteries

Carbon-coated Si and Si/B composite powders prepared by hydrocarbon gas (argon + 10 mol% propylene) pyrolysis were investigated as the anodes for lithium-ion batteries. Carbon-coated silicon anode demonstrated the first discharge and charge capacity as 1568 mAh g⁻¹ and 1242 mAh g⁻¹, respectively, with good capacity retention for 10 cycles. The capacity fading rate of carbon-coated Si/B composite anode decreased as the amounts of boron increased. In addition, the cycle life of carbon-coated Si/B/graphite composite anode has been significantly improved by using sodium carboxymethyl cellulose (NaCMC) and styrene butadiene rubber (SBR)/NaCMC mixture binders compared to the poly(vinylidene fluoride, PVdF) binder. A reversible capacity of about 550 mAh g⁻¹ has been achieved at 0.05 mAm g⁻¹ rate and its capacity could be maintained up to 450 mAh g⁻¹ at high rate of 0.2 mAm g⁻¹ even after 30 cycles. The improvement of the cycling performance is attributed to the lower interfacial resistance due to good electric contact between silicon particles and copper substrate.     

Si–Ni alloy–graphite composite synthesized by arc-melting and high-energy mechanical milling for use as an anode in lithium-ion batteries

A Si–Ni alloy and graphite composite is synthesized by arc-melting followed by high-energy mechanical milling. The alloy particles consist of an electrochemically active silicon phase with inactive phases such as NiSi₂ and NiSi distributed uniformly on the surface of the graphite. The inactive phases can accommodate the large volume changes of Si during cycling of the composite as an anode material for lithium batteries. The cycle-life of the composite increases with increase in Si content. A large reversible capacity (about 800 mAh g⁻¹) and good cycleability suggest that the composite may prove to be an alternative to conventional graphite-based anode materials for lithium-ion secondary batteries.     

Enhancement of capacity of carbon-coated Si–Cu3Si composite anode using metal–organic compound for lithium-ion batteries

A carbon-coated Si–Cu₃Si composite material is prepared using silicon and copper(II) d-gluconate powders by simple mechanical milling and pyrolysis, and is investigated as an anode material for lithium-ion batteries. In this process, the Cu₃Si and pyrolyzed carbon uniformly adhere to the surface of the silicon particles. The cycling performance of the composite material exhibits a stable capacity of 850 mAh g⁻¹ for 30 cycles. The improved cycling performance is attributed to the fact that the copper silicide and pyrolyzed carbon provide both a better electrical contact with the current–collector and a buffering effect for the volume expansion–contraction during cycling.