Fe2O3锂离子电池负极材料研究进展

Fe2O3锂离子电池负极材料因其具有的高能量密度而备受关注。但Fe2O3电极材料存在的如低导电性、充/放电过程中体积改变导致的循环稳定性差等问题限制其实际应用。介绍了高比表面积、结构稳定以及储锂动力学等因素对锂离子电池负极材料电化学性能的重要影响,综述电极活性材料纳米化、形貌控制和杂原子掺杂对Fe2O3负极材料电化学性能改善的相关研究进展,最后对Fe2O3电极材料的发展前景进行了展望。     

锂离子电池用三维氧化锡/石墨烯水凝胶负极材料

通过溶液水解反应在氧化石墨烯表面引入氧化锡(Sn O2)纳米颗粒,再经过自组装作用形成具有三维结构的氧化锡/石墨烯水凝胶(Sn O2-GH)负极材料。其中三维多孔的石墨烯水凝胶为碳质缓冲基体,Sn O2纳米颗粒为活性物质,其颗粒尺寸为2-3 nm,均匀分布在石墨烯层上,担载量可以达到54%(w,质量分数)。直接将该材料用作锂离子电池负极时,在5000 m A?g~(-1)的大电流密度下循环60次容量稳定在500 m Ah?g~(-1),电流减小到50 m A?g~(-1)循环80次后容量仍高达865 m Ah?g~(-1)。这些优异的循环稳定性和大电流充放电性能主要得益于三维石墨烯水凝胶的疏松、多孔结构和良好的导电性。石墨烯水凝胶能够提高电极比表面积,保证电解液对电极的浸润程度;内部空隙能够为锂离子的传输提供快速通道,缩短离子传输距离和时间。同时丰富的内部空间能够有效避免Sn O2纳米颗粒团聚,缓冲Sn O2巨大体积膨胀,维持电极结构的稳定性,是一种非常适于大电流充放电的锂离子电池负极材料。     

碳网封装Fe3O4/还原氧化石墨烯锂离子电池负极材料

通过简单有效的溶剂热法将Fe3 O4颗粒与氧化石墨烯(GO)进行复合,得到Fe3 O4/GO复合材料.将Fe3 O4/GO与葡萄糖进行碾磨.在高温下将GO还原成还原氧化石墨烯(rGO)的同时在Fe3 O4/rGO表面制备网状结构的导电碳层,得到三维网络传输结构C/Fe3 O4/rGO复合材料.由碳网和还原氧化石墨烯组成...     

锂离子电池TiO2纳米管负极材料

锂离子电池负极材料二氧化钛(TiO₂)由于其零应变、环境友好和高安全性近年来得到了广泛的研究,但其较低的电子电导和离子迁移率以及较低的比容量(335 mAh·g^-1)限制了其应用前景.本文梳理了一种纳米结构TiO₂纳米管(TNTs)的研究历程以及最近研究进展,综述了TNTs常见的几种制备方法,即水热法、阳极氧化法和模板法及其形成机理,归纳了各种制备方法的优缺点,讨论了制备过程中各项参量对制得TNTs的影响.阐述了其晶体结构与形貌对电化学性能的影响,指出晶格取向一致、管壁厚度小,纳米管开口且同向排列的TNTs具有更好的电化学性能.同时探讨了针对该材料电导性差、比容量低而进行的包括结构设计、掺杂、复合等一系列改进措施,指出与高电导率及高比容量材料复合是一种方便有效的改进措施.最后总结了各种改性方法取得的进展及存在的不足,展望了TNTs的研究趋势和发展前景.     

作为锂离子电池负极材料的三维有序大孔SnO2的 制备及表征

通过聚苯乙烯(PS)胶晶模板法合成了三维有序大孔(3DOM) SnO2. 运用扫描电镜、热重分析、X射线衍射、电化学充放电等多种方法对其结构和性能进行了表征和研究. SEM图表明PS胶晶模板微球排列规整, 大小均匀(直径275±10 nm), 形成多层六方紧密堆积排列; 煅烧除去模板后的3DOM SnO2呈三维多孔网络结构, 具有圆型和六边形的孔隙形貌, 其孔径大小为(215±10) nm; 孔壁由SnO2纳米晶粒组成, 壁厚为20～30 nm. XRD图谱表明经过煅烧除去模板后, 形成了纯SnO2相. 当作为锂离子电池负极材料时, 3DOM SnO2表现出较好的充放电容量和库仑效率. 此外, 这种合成方法简单、经济, 可进一步应用于其它锂离子电池材料的合成.     

锂离子电池Sb基负极材料研究进展

Sb基材料作为一类合金机制的锂离子电池负极材料,因具有比容量高、安全性好等优点受到广泛关注。 然而,由于Sb基负极材料在充放电过程中的体积效应和本身导电性较差等问题导致的循环性能不理想,制约了其作为锂离子电池负极材料的商业化应用。 本文综述了近年来在锂离子电池Sb基各类负极材料方面的研究进展,重点介绍了它们的反应机理、合成方法及电化学性能,并对Sb基负极材料的发展方向进行了展望。     

功率型锂离子电池负极材料TiO2/石墨烯的制备及其电化学性能研究

采用无表面活性剂回流法制备了蜂窝状TiO2/石墨烯(GNs)复合材料.扫描电子显微镜(SEM)及透射电子显微镜(TEM)表征结果表明,TiO2颗粒约5～10 nm,均匀地分散在石墨烯的表面.锂电池测试显示,1C充电容量稳定在240.1 mAh.g-1;30C充电容量为169.5 mAh.g-1;当电流调回1C时,其充电容量仍可完全恢复(241.7 mAh.g-1);10C 300周期循环电极容量保持率为89.8%.     

锂离子电池负极硅基材料

硅基材料由于其高电化学容量是一种非常有发展前途的锂离子电池负极材料,但其在充放电过程中体积变化大、循环寿命差、首次库仑效率低等是阻碍其商业化的主要问题.本文综述了硅在脱嵌锂时晶体结构及表/界面的变化,以及改善其电化学性能方面的研究进展,并阐述其作为锂离子电池负极材料的研究前景.     

锂离子电池Sn基合金负极材料

发展高安全性、高能量、低成本、长寿命锂离子电池是当前动力电池应用面临的巨大挑战。电池的性能主要取决于正负极电极材料的性能。Sn基合金负极具有高能量和安全特性,是一种很有产业化前景的锂离子电池负极材料。本文综述了Sn基合金电极作为锂离子电池负极的最新研究进展,对Sn基合金负极的不同制备方法进行了总结,重点介绍了锡基合金负极材料在电化学性能方面所存在的问题及其原因,包括锡基活性物质的损失、SEI膜和氧化膜的形成、纳米粒子的团聚和锂离子嵌入过程中死锂的产生等影响合金充放电性能的因素,最后展望了以提高Sn基合金负极电化学性能为目的的研究趋势。     

硅基锂离子电池负极材料

硅是目前已知比容量(4200 mAh ·g^-1)最高的锂离子电池负极材料,但由于其巨大的体积效应(> 300%),硅电极材料在充放电过程中会粉化而从集流体上剥落,使得活性物质与活性物质、活性物质与集流体之间失去电接触,同时不断形成新的固相电解质层(SEI),最终导致电化学性能的恶化。本文介绍了硅作为锂离子电池负极材料的储能及容量衰减机理,总结了通过硅材料的选择和结构设计来解决充放电过程中巨大体积效应的相关工作,并讨论了一些具有代表性的硅基复合材料的制备方法、电化学性能和相应机理,重点介绍了硅炭复合材料。另外,介绍了一些电极的处理方法和其提高硅基负极材料电化学性能的可能机理。最后,对硅基负极材料存在的问题进行了分析,并展望了其研究前景。     

Facile Synthesis of Porous Mn2O3 Nanoplates and Their Electrochemical Behavior as Anode Materials for Lithium Ion Batteries

Porous Mn₂O₃ nanoplates were prepared by a facile polyol solution method combined with a simple post‐annealing process. The porous Mn₂O₃ nanoplates were characterized by XRD, field‐emission SEM, high‐resolution TEM, and N₂ adsorption/desorption isotherm measurements. The formation process for the Mn₂O₃ nanoplates was proposed as a morphology‐conserved transformation strategy. These porous nanoplates exhibited improved electrochemical performance with excellent cycling stability and good rate capability when applied as anode materials in lithium ion batteries.     

Hierarchical Mesoporous SnO Microspheres as High Capacity Anode Materials for Sodium‐Ion Batteries

Mesoporous SnO microspheres were synthesised by a hydrothermal method using NaSO₄ as the morphology directing agent. Field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and high‐resolution transmission electron microscopy (HRTEM) analyses showed that SnO microspheres consist of nanosheets with a thickness of about 20 nm. Each nanosheet contains a mesoporous structure with a pore size of approximately 5 nm. When applied as anode materials in Na‐ion batteries, SnO microspheres exhibited high reversible sodium storage capacity, good cyclability and a satisfactory high rate performance. Through ex situ XRD analysis, it was found that Na⁺ ions first insert themselves into SnO crystals, and then react with SnO to generate crystalline Sn, followed by Na–Sn alloying with the formation of crystalline NaSn₂ phase. During the charge process, there are two slopes corresponding to the de‐alloying of Na–Sn compounds and oxidisation of Sn, respectively. The high sodium storage capacity and good electrochemical performance could be ascribed to the unique hierarchical mesoporous architecture of SnO microspheres.     

h‐BN Nanosheets as 2D Substrates to Load 0D Fe3O4 Nanoparticles: A Hybrid Anode Material for Lithium‐Ion Batteries

h‐BN, as an isoelectronic analogue of graphene, has improved thermal mechanical properties. Moreover, the liquid‐phase production of h‐BN is greener since harmful oxidants/reductants are unnecessary. Here we report a novel hybrid architecture by employing h‐BN nanosheets as 2D substrates to load 0D Fe₃O₄ nanoparticles, followed by phenol/formol carbonization to form a carbon coating. The resulting carbon‐encapsulated h‐BN@Fe₃O₄ hybrid architecture exhibits synergistic interactions: 1) The h‐BN nanosheets act as flexible 2D substrates to accommodate the volume change of the Fe₃O₄ nanoparticles; 2) The Fe₃O₄ nanoparticles serve as active materials to contribute to a high specific capacity; and 3) The carbon coating not only protects the hybrid architecture from deformation but also keeps the whole electrode highly conductive. The synergistic interactions translate into significantly enhanced electrochemical performances, laying a basis for the development of superior hybrid anode materials.     

锂离子电池纳米级负极材料的研究

综述了锂离子电池纳米级碳材料、锡基材料和合金材料近几年的研究成果及发展方向,探讨了该类材料目前存在的问题及解决的办法,对该类材料的发展趋势进行了展望.     

Two-Dimensional SnSe2/CNTs Hybrid Nanostructures as Anode Materials for High-Performance Lithium-Ion Batteries

Tin diselenide (SnSe₂), as an anode material, has outstanding potential for use in advanced lithium-ion batteries. However, like other tin-based anodes, SnSe₂ suffers from poor cycle life and low rate capability due to large volume expansion during the repeated Li⁺ insertion/de-insertion process. This work reports an effective and easy strategy to combine SnSe₂ and carbon nanotubes (CNTs) to form a SnSe₂/CNTs hybrid nanostructure. The synthesized SnSe₂ has a regular hexagonal shape with a typical 2D nanostructure and the carbon nanotubes combine well with the SnSe₂ nanosheets. The hybrid nanostructure can significantly reduce the serious damage to electrodes that occurs during electrochemical cycling processes. Remarkably, the SnSe₂/CNTs electrode exhibits a high reversible specific capacity of 457.6 mA h g⁻¹ at 0.1 C and 210.3 mA h g⁻¹ after 100 cycles. At a cycling rate of 0.5 C, the SnSe₂/CNTs electrode can still achieve a high value of 176.5 mA h g⁻¹, whereas a value of 45.8 mA h g⁻¹ is achieved for the pure SnSe₂ electrode. The enhanced electrochemical performance of the SnSe₂/CNTs electrode demonstrates its great potential for use in lithium-ion batteries. Thus, this work reports a facile approach to the synthesis of SnSe₂/CNTs as a promising anode material for lithium-ion batteries.     

A Porous Mooncake-Shaped Li4Ti5O12 Anode Material Modified by SmF3 and Its Electrochemical Performance in Lithium Ion Batteries

Reasonably designing and synthesizing advanced electrode materials is significant to enhance the electrochemical performance of lithium ion batteries (LIBs). Herein, a metal–organic framework (MOF, Mil-125) was used as a precursor and template to successfully synthesize the porous mooncake-shaped Li₄Ti₅O₁₂ (LTO) anode material assembled from nanoparticles. Even more critical, SmF₃ was used to modify the prepared porous mooncake-shaped LTO material. The SmF₃-modified LTO maintained a porous mooncake-shaped structure with a large specific surface area, and the SmF₃ nanoparticles were observed to be attach on the surface of the LTO material. It has been proven that the SmF₃ modification can further facilitate the transition from Ti⁴⁺ to Ti³⁺, reduce the polarization of electrode, decrease charge transfer impedance (R_ct) and solid electrolyte interface impedance (R_sei), and increase the lithium ion diffusion coefficient (D_Li), thereby enhancing the electrochemical performance of LTO. Therefore, the porous mooncake-shaped LTO modified using 2 wt % SmF₃ displays a large specific discharge capacity of 143.8 mAh g⁻¹ with an increment of 79.16 % compared to pure LTO at a high rate of 10 C (1 C=170 mAh g⁻¹), and shows a high retention rate of 96.4 % after 500 cycles at 5 C-rate.     

MoO3纳米带/RGO复合材料的制备及其电化学性能研究

以水杨酸为模板剂和还原剂,采用水热法制备得到了一种MoO₃纳米带/RGO复合材料。利用XRD、SEM、TEM、拉曼光谱、恒流充放电、交流阻抗等手段对样品的结构、形貌以及电化学性能进行表征。测试结果表明,MoO₃纳米带/RGO复合材料作为锂离子电池负极材料,在50mA·g^-1的电流密度下可逆比容量为1000mAh·g^-1,循环50次后比容量还保持在950mAh·g^-1,相比于MoO₃纳米带其容量保持能力和循环性能得到了显著改善。     

MoO_3纳米带/RGO复合材料的制备及其电化学性能研究

以水杨酸为模板剂和还原剂,采用水热法制备得到了一种MoO3纳米带/RGO复合材料。利用XRD、SEM、TEM、拉曼光谱、恒流充放电、交流阻抗等手段对样品的结构、形貌以及电化学性能进行表征。测试结果表明,MoO3纳米带/RGO复合材料作为锂离子电池负极材料,在50 m A·g-1的电流密度下可逆比容量为1 000 m Ah·g-1,循环50次后比容量还保持在950 m Ah·g-1,相比于MoO3纳米带其容量保持能力和循环性能得到了显著改善。     

纳米锡/硬碳复合材料作为嵌锂负极的研究

利用金属铁和钴纳米颗粒的催化活化作用,制备了多孔硬碳球.应用聚焦离子束切割技术,观察到扩孔后的硬碳球中充满彼此连通的发达中孔.在此多孔硬碳球中填入纳米锡(Sn)颗粒,对复合材料的电化学性能进行了测试.     

Boosting the Energy Density of Flexible Asymmetric Supercapacitor with Three Dimensional Fe2O3 Composite Brush Anode

Flexible asymmetric supercapacitor is fabricated with three dimensional(3D)Fe2O3/Ni(OH)2 composite brush anode and Ni(OH)2/MoO2 honeycomb cathode.Particularly for 3D composite brush anode,a layer of thin Fe2O3 film is firmly adhered on a 3D Ni brush current collector with the assist of Ni(OH)2,functioning as both adherence layer and pseudocapacitive active material.The unique 3D Ni brush current collector possesses large surface area and stretching architecture,which facilitate to achieve the composite anode with high gravimetric capacitance of 2158 F/g.In terms of cathode,Ni(OH)2 and MoO2 have a synergistic effect to improve the specific capacitance,and the resulting Ni(OH)2/MoO2 honeycomb cathode shows a very high gravimetric capacitance up to 3264 F/g.The asymmetric supercapacitor(ASC)has balanced cathode and anode,and exhibits an ultrahigh gravimetric capacitance of 1427 F/g and an energy density of 476 W·h/kg.The energy density of ASC is 3-4 times higher than those of other reported aqueous electrolyte-based supercapacitors and even comparable to that of commercial lithium ion batteries.The device also shows marginal capacitance degradation after 1000 cycles'bending test,demonstrating its potency in the application of flexible energy storage devices.