LiNbO3-coated LiCoO2 as cathode material for all solid-state lithium secondary batteries

The further enhancement of high-rate capabilities for all solid-state lithium secondary batteries is reported. A LiNbO₃ layer of nanometer thickness was interposed between LiCoO₂ and sulfide solid electrolyte as buffer layer. This greatly reduced the interfacial resistance in the cathode and enhanced the high-rate capabilities of solid-state lithium batteries, providing good prospects for practical application of lithium secondary batteries free from safety issues.     

熔融浸渍法制备锂离子电池正极材料LiMn2O4的研究

采用LiNO3和MnO2为原料,在650℃下制备了尖晶石型的LiMn2O4.通过X射线衍射、扫描电子显微镜、热重分析和电化学性能测试,发现该化合物具有很高的放电比容量和较好的循环性能,首次放电比容量可达到122 mA·h/g.并对循环性能衰减的各种因素进行了讨论.     

锂离子电池正极材料LiFePO4的密度泛函研究

采用密度泛函(B3LYP)方法计算锂离子电池正极材料LiFePO4/FePO4,净电荷和共价键级的计算结果都表明磷氧原子间作用力最强,锂氧原子间作用力最弱,有利于Li离子在晶格中的自由移动.以Li/LiFePO4锂离子电池的平均电压为3.2 V,和实验值3.4 V基本一致.态密度分析表明FePO4和LiFePO4都是典型的半导体,O原子轨道主要贡献总态密度靠费米能级价带一侧,Fe原子轨道主要贡献总态密度靠费米能级导带一侧.     

A novel sandwiched membrane as polymer electrolyte for lithium ion battery

A novel kind of sandwiched polymer membrane was prepared by coating three layers of poly(vinyl difluoride) (PVDF), poly(methyl methacrylate) (PMMA) and PVDF, separately. Its characteristics were investigated by scanning electron microscopy, FT-IR, X-ray diffraction, and differential thermal analysis. It consists of two phases. The outer PVDF layers are porous, and the inner PMMA layer is solid. Since the PMMA has a good compatibility with the carbonate-based liquid electrolyte, the membrane can easily absorb the electrolyte to form a gelled polymer electrolyte (GPE). As a result, the evaporation peak of the liquid electrolyte is increased to 160 °C. Due to very low evaporation of the liquid electrolyte, LiCoO₂ shows good cycling behavior in the range of 4.4–3.0 V when this GPE is used as the separator and polymer electrolyte, and lithium as the counter and reference electrode. This unique sandwiched membrane is promising for application in scale-up lithium ion batteries with high safety and high energy density.     

Ta2O5 nanoparticles as an anode material for lithium ion battery

Journal of Solid State Electrochemistry - Ta2O5 is one of the promising anode materials for lithium ion battery application undergoing conversion reaction in combination with an extrinsic...     

A novel approach to massive preparation of LiV3O8 as a cathode material for lithium rechargeable battery

The layered cathode materials of LiV₃O₈ were successfully prepared for the lithium rechargeable battery via a wet-chemistry synthesis method. The as-synthesized materials were characterized by XRD (powder X-ray diffraction), SEM (scanning electron microscope) and galvanostatic charge-discharge test. The results indicate that this soft-synthesis technique offers reduced calcinations temperature, preferred surface morphology and better electrochemical performance. Among the thus-prepared materials, the material obtained at 350 °C demonstrates the first discharge capacity as high as 308 mAh g^-1 in the range of 4.0 ～1.7 V at a current rate of 30 mA g^-1 and remains at a stable discharge capacity of 250 mAh g^-1 within 30 cycles.     

Wet coordination method to prepare carbon-coated Li3V2(PO4)3 cathode material for lithium ion batteries

A convenient method named wet coordination is used to prepare the sample or carbon-coated Li₃V₂(PO₄)₃ in the furnace with a flowing argon atmosphere at 600 °C for 1 h. The sample is characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM) and energy dispersive analysis of X-rays (EDAX). Galvanostatic charge–discharge between 3.3 and 4.3 V (vs. Li/Li⁺) shows that the sample exhibits a high discharge capacity of 128 mAh g^?1 with a good reversible performance under a current density of 95 mA g^?1. It suggests that carbon-coated Li₃V₂(PO₄)₃ with good electrochemical performance can be obtained via this method, which is suitable for large-scale production.     

Nb2O5-carbon core-shell nanocomposite as anode material for lithium ion battery

Nb₂O₅-carbon nanocomposite is synthesized through a facile one-step hydrothermal reaction from sucrose as the carbon source, and studied as an anode material for high-performance lithium ion battery. The structural characterizations reveal that the nanocomposite possesses a core-shell structure with a thin layer of carbon shell homogeneously coated on the Nb₂O₅ nanocrystals. Such a unique structure enables the composite electrode with a long cycle life by preventing the Nb₂O₅ from volume change and pulverization during the charge-discharge process. In addition, the carbon shell efficiently improves the rate capability. Even at a current density of 500 mA·g^?1, the composite electrode still exhibits a specific capacity of ～100 mAh·g^?1. These results suggest the possibility to utilize the Nb₂O₅-carbon core-shell composite as a high performance anode material in the practical application of lithium ion battery.     

Aliphatic thioether polymers as novel cathode active materials for rechargeable lithium battery

Two aliphatic thioether polymers, poly[methanetetryl-tetra(thiomethylene)] (PMTTM) and poly(2,4-dithiopentanylene) (PDTP) were designed, synthesized, characterized and tested as cathode active materials. The chemical structure of polymers was confirmed by FT-IR, FT-Raman, and XPS spectral analysis. Both polymers were found to have electrochemical activity as cathode materials for rechargeable lithium battery by the electrochemical tests. The specific capacity of PMTTM was 504 mA h g⁻¹ at the third cycle and faded to 200 mA h g⁻¹ after 10 cycles; PDTP showed low and stable specific capacity around 100 mA h g⁻¹ even after 50 cycles. The specific capacity of fully saturated aliphatic thioether polymers demonstrated that thioether bonds offered energy storage. It was proposed that thioether bond was oxidized to form thioether cations with the help of ether solvents.     

Silicon nanowire fabric as a lithium ion battery electrode material

A nonwoven fabric with paperlike qualities composed of silicon nanowires is reported. The nanowires, made by the supercritical-fluid-liquid-solid process, are crystalline, range in diameter from 10 to 50 nm with an average length of >100 μm, and are coated with a thin chemisorbed polyphenylsilane shell. About 90% of the nanowire fabric volume is void space. Thermal annealing of the nanowire fabric in a reducing environment converts the polyphenylsilane coating to a carbonaceous layer that significantly increases the electrical conductivity of the material. This makes the nanowire fabric useful as a self-supporting, mechanically flexible, high-energy-storage anode material in a lithium ion battery. Anode capacities of more than 800 mA h g(-1) were achieved without the addition of conductive carbon or binder.     

Volatile single-source molecular precursor for the lithium ion battery cathode

The first single-source molecular precursor for a lithium-manganese cathode material is reported. Heterometallic β-diketonate LiMn(2)(thd)(5) (1, thd = 2,2,6,6-tetramethyl-3,5-heptanedionate) was obtained in high yield by simple one-step solid-state reactions employing commercially available reagents. Substantial scale-up preparation of 1 was achieved using a solution approach. The crystal structure of the precursor contains discrete Li:Mn = 1:2 trinuclear molecules held together by bridging diketonate ligands. The complex is relatively stable in open air, highly volatile, and soluble in all common solvents. It was confirmed to retain its heterometallic structure in solutions of non-coordinating solvents. The heterometallic diketonate 1 was shown to exhibit clean, low-temperature decomposition in air/oxygen that results in nanosized particles of spinel-type oxide LiMn(2)O(4), one of the leading cathode materials for lithium ion batteries.     

High capacity carbon-coated Si70Sn30 nanoalloys for lithium battery anode material

Carbon-coated Si70Sn30 nanoalloys with a particle size < 10 nm were prepared from butyl-capped analogues via firing at 900 degrees C under a vacuum showed a reversible capacity of 2032 mAh g(-1) and excellent capacity retention.     

Improved disordered carbon as high performance anode material for lithium ion battery

A sulfur-substituted disordered carbon is explored as anode material for lithium-ion battery. Its physical and electrochemical properties are characterized by a variety of techniques such as powder X-ray diffraction, element analysis, Fourier transform infrared spectrum, scanning electron microscopy, and typical electrochemical tests. Electrochemical tests show the activated carbon displays a first cycle discharge capacity of 1,216 mAh·g⁻¹. It also has a remarkable cycling stability with an average capacity fade of 0.92% per cycle from 11th to 100th cycle in the range of 0.01–3.00 V versus metallic lithium at a current density of 100 mA·g⁻¹. After 100 cycles, the electrode still maintained a capacity of 420 mAh·g⁻¹.     

A graphene-amorphous FePO4 hollow nanosphere hybrid as a cathode material for lithium ion batteries

Amorphous FePO(4) hollow nanospheres were directly grown on graphene for use as a cathode material in lithium ion batteries. This hybrid exhibits high rate capability and good cycle stability because of efficient Li(+) ion diffusion through the thin wall of the hollow nanospheres and fast electron transport through the graphene.     

Improved electrochemical properties of Sn-doped TiO2 nanotube as an anode material for lithium ion battery

Anatase TiO₂ nanotube was doped with different contents of Sn (3, 5, and 7 at.%) through sol-gel method and subsequent hydrothermal process. X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), Brunauer-Emmett-Teller (BET), and Hall effect measurement are utilized to characterize the structures, components, chemical environments, morphologies, specific areas, and electronic conductivities of the samples. The investigation in cycling performances demonstrates that 5 at.% Sn-doped TiO₂ nanotube exhibits the best cycling stability, with specific capacity of 386 mAh g^?1 and coulombic efficiency of 99.2 % after 50 cycles at 0.1 C, much higher than those of the other Sn-doped samples and pristine TiO₂ nanotube. The improved electrochemical performances of Sn-doped TiO₂ nanotube are attributed to the increase of electronic conductivity and therefore enhance the reversible capacity of the material.     

方铁锰矿Mn2O3作为正极材料的高比容量可充电水性锌离子电池

由于具有低成本、高安全性、组装简易方便等优点,水性可充电锌离子二次电池被认为是太阳能和风能的最佳储能装置,尤其是锌锰二次电池.目前,锰正极材料的研究较多集中在二氧化锰上,同时,也有关于Mn2O3的研究,但比容量及能量密度皆较低.本文合成了方铁锰矿Mn2O3并将其用于水性锌离子电池的正极材料,在0.2C倍率下充放时,获得...     

Graphene oxide assisted facile hydrothermal synthesis of LiMn0.6Fe0.4PO4 nanoparticles as cathode material for lithium ion battery

Assisted by graphene oxide（GO）,nano-sized LiMn0.6Fe0.4PO4 with excellent electrochemical performance was prepared by a facile hydrothermal method as cathode material for lithium ion battery.SEM and TEM images indicate that the particle size of LiMn0.6Fe0.4PO4（S2）was about 80 nm in diameter.The discharge capacity of LiMn0.6Fe0.4PO4 nanoparticles was 140.3 mAh-g^1 in the first cycle.It showed that graphene oxide was able to restrict the growth of LiMn0.6Fe0.4PO4 and it in situ reduction of GO could improve the electrical conductivity of LiMn0.6Fe0.4PO4 material.     

Thermal explosion synthesis of LiFePO4 as a cathode material for lithium ion batteries

Research on Chemical Intermediates - Olivine-type LiFePO4 cathode material was successfully synthesized by a simple method of thermal explosion (TE) using hexamethylenetetramine (C6H12N4) as fuel....     

N-doped coaxial CNTs@a-Fe_2O_3@C nanofibers as anode material for high performance lithium ion battery

N-doped coaxial CNTs@α-Fe_2O_3@C nanofibers have been successfully synthesized according to a facile solvothermal/hydrothermal method.The obtained CNTs@α-Fe_2O_3@C nanofibers composites exhibited special three-dimensional(3-D)network structure,which endows they promising candidate for anode materials of lithium ion battery.The coaxial property of CNTs@α-Fe_2O_3@C nanofibers could significantly improve the cycling and rate performance owing to the acceleration of charge/electron transfer,improvement of conductivity,maintaining of structural integrity and inhibiting the aggregation.Theα-Fe_2O_3nanoparticles with small size and high percentage of N-doped amount could further improve the electrochemical performance.As for the CNT@α-Fe_2O_3@C nanofibers,the capacity presented a high value of1255.4 mAh/g at 0.1 C,and retained at 1213.4 mAh/g after 60 cycles.Even at high rate of 5 C,the capacity still exhibited as high as 319 mAh/g.The results indicated that the synthesized N-doped coaxial CNTs@α-Fe_2O_3@C nanofibers exhibited high cycling and rate performance.     

Tremella-like molybdenum dioxide consisting of nanosheets as an anode material for lithium ion battery

Tremella-like structured MoO₂ consisting of nanosheets was obtained via a Fe₂O₃-assisted hydrothermal reduction of MoO₃ in ethylenediamine aqueous solution. The as-prepared product was characterized and tested with scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), cyclic voltammetry (CV) and capacity measurement as anode material for lithium ion batteries. This structured MoO₂ shows very high reversible capacity (>600 mA h g⁻¹), good rate capability and cycling performance, presenting potential application as anode material for lithium ion batteries with high rate capability and high capacity.