Optimization of battery life and capacity by setting dense mesopores on the surface of nanosheets used as electrode

Nanosheets with mesopores on the surface have been prepared using molybdenum trioxide(α-MoO_3).The effect of mesopores on the performance of the electrode remains elusive.The MoO_3 nanosheets obtained in this study exhibited great battery performance, including good capacity, prolonged recycling life cycles, and excellent rate performance; e.g., 780 mAh/g when charged under a super high current-density of 1000 m A/g.These nanosheets demonstrated excellent stability, maintaining a capacity of 1189 mAh/g after 20 cycles, and 1075 mAh/g after 50 cycles; thus preventing the capacity to decrease to values under the scanning rate of 100 mA/g.These high-purity MoO_3 nanosheets are well-ordered and have dense mesopores on the surface; these micropores contribute to the excellent electrode performance of the host electrode materials; the performance parameters include prolonged battery life and capacity.Setting mesopores or active sites on the electrode surface can be an alternative way to obtain stable electrodes in the future.     

强耦合非晶态Sb2S3球与碳纳米管中的钠离子和锂离子存储

A facile one-step strategy involving the reaction of antimony chloride with thioacetamide at room temperature is successfully developed for the synthesis of strongly coupled amorphous Sb₂S₃ spheres and carbon nanotubes (CNTs). Benefiting from the unique amorphous structure and its strongly coupled effect with the conductive network of CNTs, this hybrid electrode (Sb₂S₃@CNTs) exhibits remarkable sodium and lithium storage properties with high capacity, good cyclability, and prominent rate capability. For sodium storage, a high capacity of 814 mAh·g?1 at 50 mA·g?1 is delivered by the electrode, and a capacity of 732 mAh·g?1 can still be obtained after 110 cycles. Even up to 2000 mA·g?1, a specific capacity of 584 mAh·g?1 can be achieved. For lithium storage, the electrode exhibits high capacities of 1136 and 704 mAh·g?1 at 100 and 2000 mA·g?1, respectively. Moreover, the cell holds a capacity of 1104 mAh·g?1 under 100 mA·g?1 over 110 cycles. Simple preparation and remarkable electrochemical properties make the Sb₂S₃@CNTs electrode a promising anode for both sodium-ion (SIBs) and lithium-ion batteries (LIBs).     

CoO/SnO2@NC/S复合材料的制备及其应用于高稳定性锂硫电池正极材料

To improve the sulfur loading capacity of lithium-sulfur batteries (Li–S batteries) cathode and avoid the inevitable “shuttle effect”, hollow N doped carbon coated CoO/SnO₂ (CoO/SnO₂@NC) composite has been designed and prepared by a hydrothermal-calcination method. The specific surface area of CoO/SnO₂@NC composite is 85.464 m2·g–1, and the pore volume is 0.1189 cm3·g–1. The hollow core-shell structure as a carrier has a sulfur loading amount of 66.10%. The initial specific capacity of the assembled Li–S batteries is 395.7 mAh·g–1 at 0.2 C, which maintains 302.7 mAh·g–1 after 400 cycles. When the rate increases to 2.5 C, the specific capacity still has 221.2 mAh·g–1. The excellent lithium storage performance is attributed to the core-shell structure with high specific surface area and porosity. This structure effectively increases the sulfur loading, enhances the chemical adsorption of lithium polysulfides, and reduces direct contact between CoO/SnO₂ and the electrolyte.     

Lithium-ion full cell with high energy density using nickel-rich LiNi0.8Co0.1Mn0.1O2 cathode and SiO-C composite anode

A high-energy-density Li-ion battery with excellent rate capability and long cycle life was fabricated with a Ni-rich layered LiNi_0.8Mn_0.1Co_0.1O₂ cathode and SiO-C composite anode. The LiNi_0.8Mn_0.1Co_0.1O₂ and SiO-C exhibited excellent electrochemical performance in both half and full cells. Specifically, when integrated into a full cell configuration, a high energy density (280 Wh·kg-1) with excellent rate capability and long cycle life was attained. At 0.5C, the full cell retained 80% of its initial capacity after 200 charge/discharge cycles, and 60% after 600 cycles, indicating robust structural tolerance for the repeated insertion/extraction of Li+ ions. The rate performance showed that, at high rate of 1C and 2C, 96.8% and 93% of the initial capacity were retained, respectively. The results demonstrate strong potential for the development of high energy density Li-ion batteries for practical applications.     

Facile hydrothermal and sol-gel synthesis of novel Sn-Co/C composite as superior anodes for Li-ion batteries

As an anode material in lithium ion battery, the Sn-Co/C composite electrode materials have been successfully synthesized by hydrothermal and solgel methods, respectively. The resultant composites were mainly composed of Snbased oxides, nanometer Sn-Co alloy and carbon. Carbon and Co, acting as buffer materials, can accommodate to the large volume change of active Sn during the discharge-charge process, thus improving the cycling stability. Although charge/discharge curves revealed the excellent cycle performance for samples synthesized by both methods, composites obtained by the sol-gel showed a better dispersion effect of nanoparticles on the carbon matrix and possessed much more improved stable capacity with 624.9 mAh g-1 over 100 cycles and that by hydrothermal method only exhibited ～299.3 mAh g-1. Therefore, the Sn-Co/C composites obtained by solgel synthesis method could be a perfect candidate for anode material of Liion storage battery.     

Synthesis and Electrochemical Properties of Nanostructured Cathode Materials for Lithium Batteries

1 Results For electrode materials in lithium batteries,a high surface area can provide higher electrode/electrolyte contact areas,thus eventually causing the shorter diffusion paths with the particles,and provides more facile intercalation for Li ions[1-4].In addition,reduced strain of intercalation and contributions from charge storage at the surface may also contribute to Li capacity,compared with bulk counterparts.In this regard,I am going to talk about the preparation and electrochemical properties of the cathodes with various nanostructures,such as nanoplate,nanoparticle,nanowire,and hollow,mesopores.For instance,layered Li0.88[Li0.18Co0.33Mn0.49]O2 nanowires prepared by using Co0.4Mn0.6O2 nanowires as a precursor at 200 ℃ showed superior rate capability,compared with the bulk analogues,showing reversible capacity of 230 mAh/g between 2 and 4.8 V even at high rate of 3 600 mA/g.     

碳点修饰硅在锂离子电池中的应用研究

Silicon (Si) particles were functionalized using carbon dots (CDs) to enhance the interaction between the Si particles and the binders. First, CDs rich in polar groups were synthesized using a simple hydrothermal method. Then, CDs were loaded on the Si surface by impregnation to obtain the functionalized Si particles (Si/CDs). The phases and microstructures of the Si/CDs were observed using Fourier-transform infrared reflection, X-ray diffraction, scanning electron microscopy, and high-resolution transmission electron microscopy. Si/CDs were used as the active material of the anode for electrochemical performance experiments. The electrochemical performance of the Si/CD electrode was assessed using cyclic voltammetry, electrochemical impedance spectroscopy, and constant current charge and discharge experiment. The electrodes prepared with Si/CDs showed good mechanical structure stability and electrochemical performance. After 150 cycles at 0.2 C, the capacity retention rate of the Si/CD electrode was 64.0%, which is twice as much as that of pure Si electrode under the same test conditions.     

Low temperature synthesis of NiO/Co3O4 composite nanosheets as high performance Li-ion battery anode materials

NiO/Co3O4 composite nanosheets have been synthesized via a facile method at low temperature for the first time.The as prepared materials were characterized by X-ray powder diffraction(XRD) and transmission electron microscopy(TEM),and the performance of Li-ion batteries(LIBs) as anode materials were also studied.By controlling the atom ratio of Ni:Co,not only the size of the nanosheets can be controlled,the electrode’s conductivity and stability could also be greatly improved.The composite material showed a stable capacity retention during cycling(87% of the second capacity was retained after 15 cycles) even at a relatively large current rate(400 mA/g).The NiO/Co3O4 nanosheet might be promising candidate anode materials in high performance Li-ion batteries.     

Superior sodium and lithium storage in strongly coupled amorphous Sb_2S_3 spheres and carbon nanotubes

A facile one-step strategy involving the reaction of antimony chloride with thioacetamide at room temperature is successfully developed for the synthesis of strongly coupled amorphous Sb_2S_3 spheres and carbon nanotubes(CNTs). Benefiting from the unique amorphous structure and its strongly coupled effect with the conductive network of CNTs, this hybrid electrode(Sb_2S_3@CNTs) exhibits remarkable sodium and lithium storage properties with high capacity, good cyclability, and prominent rate capability. For sodium storage, a high capacity of 814 mAh·g~(-1) at 50 mA·g~(-1) is delivered by the electrode, and a capacity of 732 mAh·g~(-1) can still be obtained after 110 cycles. Even up to 2000 m A·g~(-1), a specific capacity of 584 mAh·g~(-1) can be achieved. For lithium storage, the electrode exhibits high capacities of 1136 and 704 m Ah·g~(-1) at 100 and 2000 mA·g~(-1), respectively. Moreover, the cell holds a capacity of 1104 mAh·g~(-1) under 100 mA·g~(-1) over 110 cycles.Simple preparation and remarkable electrochemical properties make the Sb_2S_3@CNTs electrode a promising anode for both sodium-ion(SIBs)and lithium-ion batteries(LIBs).     

具有良好可再生性的新型二氧化硅磁性氧化石墨烯纳米复合材料

Graphene oxide (GO) wrapped Fe₃O₄ nanoparticles (NPs) were prepared by coating the Fe₃O₄ NPs with a SiO₂ layer, and then modifying by amino groups, which interact with the GO nanosheets to form covalent bonding. The SiO₂ coating layer plays a key role in integrating the magnetic nanoparticles with the GO nanosheets. The effect of the amount of SiO₂ on the morphology, structure, adsorption, and regenerability of the composites was studied in detail. An appropriate SiO₂ layer can effectively induce the GO nanosheets to completely wrap the Fe₃O₄ NPs, forming a core-shell Fe₃O₄@SiO₂@GO composite where Fe₃O₄@SiO₂ NPs are firmly encapsulated by GO nanosheets. The optimized Fe₃O₄@SiO₂@GO sample exhibits a high saturated adsorption capacity of 253 mg·g?1 Pb(II) cations from wastewater, and the adsorption process is well fitted by Langmuir adsorption model. Notably, the composite displays excellent regeneration, maintaining a ~90% adsorption capacity for five cycles, while other samples decrease their adsorption capacity rapidly. This work provides a theoretical guidance to improve the regeneration of the GO-based adsorbents.     

CoMoO4水热法制备及其在锂/钠离子电池中的应用

碳基负极材料比容量低,无法满足高能量密度电池的需求.为了进一步寻找高容量长循环寿命的电池负极材料,采用水热反应法制备了自支撑CoMoO₄负极,通过X射线衍射（XRD）和扫描电子显微镜（SEM）对材料的结构、形貌进行表征,利用循环伏安法和恒电流充/放电等技术对比研究了材料在锂/钠离子电池中的电化学性能.结果表明,CoMoO₄负极在锂离子电池中的首次可逆比容量为1 403.6 mAh/g,首次库伦效率为146.5%,在100 mA/g电流密度下经50次循环后仍然高达793.6 mAh/g;而CoMoO₄负极在钠离子电池中首次可逆比容量仅为314.2 mAh/g,但经50次循环后容量保持率仍有76.4 %.该自支撑负极无需导电剂和粘结剂,电极材料与泡沫镍结合力强,具有优异的循环稳定性.     

High-performance lithium–sulfur battery based on porous N-rich g-C3N4 nan-otubes via a self-template method

The commercial development of lithium–sulfur batteries (Li–S) is severely limited by the shuttle effect of lithium polysulfides (LPSs) and the non-conductivity of sulfur. Herein, porous g-C3N4 nanotubes (PCNNTs) are synthesized via a self-template method and util-ized as an efficient sulfur host material. The one-dimensional PCNNTs have a high specific surface area (143.47 m2·g?1) and an abundance of macro-/mesopores, which could achieve a high sulfur loading rate of 74.7wt%. A Li–S battery bearing the PCNNTs/S composite as a cathode displays a low capacity decay of 0.021% per cycle over 800 cycles at 0.5 C with an initial capacity of 704.8 mAh·g?1. PCNNTs with a tubular structure could alleviate the volume expansion caused by sulfur and lithium sulfide during charge/discharge cycling. High N contents could greatly enhance the adsorption capacity of the carbon nitride for LPSs. These synergistic effects contribute to the excellent cycling stability and rate performance of the PCNNTs/S composite electrode.     

锂离子电池三维多孔硅/银复合材料负极设计及性能

以商品单质硅为原料, 利用金属辅助化学刻蚀方法结合化学镀方法制备了三 维多孔硅/银复合负极材料, 采用X射线粉末衍射仪、场发射扫描电镜及比表面与孔隙度分析 仪对其组成、结构、比表面积及孔隙率进行研究, 随后对其电化学性能进行研究. 结果表明, 三 维多孔硅呈现狭缝型的介孔, 平均孔径宽度为 12.5 nm, 比表面积达到 6.083 m$^{2}$/g. 三维多孔硅/银复合材料在 420 mA/g 条件下恒流充放电, 首循环放电比容量 2 822 mA$\cdot$h/g, 首循环库仑效率 87.8%, 经过 50 个循环后容量仍保持有 832 mA$\cdot$h/g. 研究表明: 三维多孔结构和银包覆层可以缓解嵌锂/脱锂时硅巨大的体积效应; 银包覆层可以改善硅基负极材料的电化学性能.     

无粘结剂的柔性硫/碳纤维布电极的制备及电化学性能研究

以碳布为基底,通过浸渍法成功制备了柔性硫/碳纤维布电极.制备的柔性硫/碳纤维布电极无需添加导电剂和粘接剂,可直接用作硫正极极片组装电池,大大简化了电池制备工艺.电化学测试结果表明,硫含量为56.77%(质量分数)的硫/碳纤维布电极展现出了最好的电化学性能,即在0.1A/g电流密度下的可逆放电比容量达1 394mAh/g;充放电循环测试100次后,可逆放电容量仍然维持在733mAh/g.电化学性能的提高主要归因于碳纤维本身的导电性、柔韧性以及大量碳纤维相互交错互联的导电网络.     

石墨烯/Cu-MOF锂电池负极材料的制备及电化学性能研究

金属有机骨架化合物是一种由金属离子与有机配体通过配位键或共价键合成的新型的电极材料。然而,其低的电子导电率和严重的不可逆锂存储制约了该材料在锂电池领域的实际应用。石墨烯具有一系列独特属性,如高的导电率、高表面积、化学稳定性，机械强度和柔韧性,多孔结构。通常用来掺杂在电极材料中以提高循环性能和增加电池的容量。在本实验中,我们研究了Cu-MOF掺杂石墨烯(Cu-MOF/RGO)作为锂电负极材料的电化学性能。结果表明,在充放电电流密度为50 mA g-1时，充放电循环50次后，材料的放电比容量可达到520 mAh g-1。同时该材料也显示出较好的倍率性能和较高的库仑效率。由此可以看出Cu-MOF/RGO是一种具有前景的锂离子电池负极材料。     

石墨烯的制备及其作为锂离子电池负极的性能

为更好地研究石墨烯作为锂离子电池负极的性能,采用改进的Hummers方法,以天然鳞片石墨为原料,设计正交实验。通过改变插层剂的组成、氧化剂的比例、氧化反应时间、温度等反应参数来优化石墨烯的制备工艺,并通过XRD、FTIR、Raman和电池充放电测试等方法对产物的组成、结构和电化学性能进行表征。结果表明：石墨经氧化后形成了含有C=0、-COOH和C-O-C等官能团的石墨层间化合物;Raman光谱中rGO的积分强度比（ID／IC）比GO明显降低;在74．4mA／g约为0．1C的电流密度下进行电池充放电,rGO负极的首次放电容量为700mAh／g,30次循环电池放电性能稳定,可逆容量为350mAh／g。     

在高倍率部分荷电态下三维石墨烯对铅酸电池寿命的影响

采用一步水热法制备出三维多孔的石墨烯（3D-rGO），将不同质量分数的3D-rGO添加到负极活性物质中，制备出铅炭电池，并研究其电化学性能. 结果表明，随着3D-rGO质量分数的增加，在高倍率部分荷电状态（HRPSoC）下，不同电池的循环寿命先增大后减小，其中添加3D-rGO质量分数为1.0%的电池在HRPSoC下的循环性能最好，其初始放电容量(0.05C, 185.36 mAh/g)比普通蓄电池(161.94 mAh/g)高14.46%. 循环寿命达到26 425次，比普通铅酸电池的寿命（8 142次）延长了224%.     

高能量密度全固态锂金属电池Li6.4La3Zr1.4Ta0.6O12基锂硼负极的制备及性能

采用熔融态金属锂与高纯硼粉复合制备了锂硼复合材料并应用于固态电解质(Li_6.4La₃Zr_1.4Ta_0.6O₁₂, LLZTO)制作对称电池，对比研究了锂硼复合固态对称电池与锂金属固态对称电池的电化学性能。结果表明:锂硼复合固态电池界面阻抗(约6 Ω/cm2)小于金属锂固态电池的界面阻抗(约103 Ω/cm2)，说明锂硼复合电极和固态电解质接触良好；在400 μA/cm2的电流密度下进行充放电测试，锂硼复合固态对称电池可以稳定循环250次以上，而金属锂固态电池很快失效；锂硼复合固态对称电池在0.1 mAh保持容量下的临界电流密度达到2 700 μA/cm2，在0.1 mA/cm2电流密度下的面容量可达12 mAh/cm2。研究表明该锂硼复合固态对称电池具有优异的循环性能。     

电纺自支撑空穴硅碳纳米纤维在高性能锂离子电池阳极材料中的应用

硅纳米颗粒（ SiNPs）加入到聚丙烯腈（ PAN）/DMF溶液中混合均匀,通过静电纺丝、预氧化及碳化过程制备得到包含SiNPs的碳纤维膜（ CNFs）,然后经过HF酸处理形成自支撑空穴状硅碳纳米纤维膜（ H-Si-CNFs）,直接用作锂离子电池的阳极材料。通过SEM、TEM和XRD等对复合材料的形貌、结构和组成进行表征分析,并运用充放电测试仪对电池循环性能以及储能机理进行研究。结果表明这种H-Si-CNFs电极具有良好的循环性能,其中含10;硅粒子的 H-Si-CNFs在100 mA·g-1充放电,首次可逆容量达到了607 mAh·g-1,经过40次循环后的容量保留率仍有92;。     

具有微纳结构的FeS_2的制备及其储锂性能研究

金属硫化物具有较大的理论容量,有望成为下一代的锂电池负极材料,但是充放电过程中材料发生严重的膨胀/收缩、晶体粉化,使得材料的比容量迅速衰减.本文以铁醇盐为原料制备具有花状微纳结构的FeS_2,以达到抑制材料粉化效果.结果显示,300℃热处理得到的FeS_2样品能够充分保持中间体铁醇盐的花状微纳结构,结晶度高.450℃处理得到的样品表面为多孔状结构,而800℃处理未得到目标产物,样品分子式是Fe_9S_(10).电化学测试结果表明:300℃所得产物具有1 484.3mA·h/g的放电比容量,高于450℃的产物(1 326.7mA·h/g);在电流密度为200mA/g条件下,100次充放电循环后,300℃所得产物的放电比容量为480.8mA·h/g,远高于450℃所得产物的放电比容量(215.8mA·h/g).研究结果表明具有花状微纳结构对材料的粉化现象有较好的抑制作用.