Mesoporous Fe2O3 nanoparticles as high performance anode materials for lithium-ion batteries

This work introduces an effective, inexpensive, and large-scale production approach to the synthesis of Fe₂O₃ nanoparticles with a favorable configuration that 5 nm iron oxide domains in diameter assembled into a mesoporous network. The phase structure, morphology, and pore nature were characterized systematically. When used as anode materials for lithium-ion batteries, the mesoporous Fe₂O₃ nanoparticles exhibit excellent cycling performance (1009 mA h g^− 1 at 100 mA g^− 1 up to 230 cycles) and rate capability (reversible charging capacity of 420 mA h g^− 1 at 1000 mA g^− 1 during 230 cycles). This research suggests that the mesoporous Fe₂O₃ nanoparticles could be suitable as a high rate performance anode material for lithium-ion batteries.     

CoV2O6纳米线／微米棒的制备及其在锂离子电池中的应用

采用水热法制备了纳米线／微米棒结构的CoV2O6电极材料,并探讨了纳米线／微米棒的形成机理．通过XRD、BET、SEM、TEM／HRTEM等测试手段对合成产物的结构、形貌、组成、表面性质进行了表征,结果表明,水热条件例如反应温度、反应时间对于产物的结构和形貌起关键作用．在220℃,水热反应1h可以得到直径为60nm的CoV2O6纳米线,而在220℃,水热反应6h可以得到直径10μm的CoV2O6微米棒．研究了CoV2O6纳米线／微米棒作为锂离子电池负极材料的电化学性能,结果显示,与CoV2O6微米棒相比,CoV2O6纳米线具有高的初始放电容量（1235mAh/g）和较好的循环稳定性,CoV2O6纳米线有希望作为锂离子电池的负极材料．     

Hydrothermal synthesis of hexagonal WO3 nanowires with high aspect ratio and their electrochemical properties for lithium-ion batteries

One dimensional WO₃ nanowires with high aspect ratio of >200 were synthesized by hydrothermal method. The effects of reaction temperature and time on phase and morphologies were studied and discussed. In this research, a suitable hydrothermal condition is at 200°C for 48 h. XRD, SEM, and TEM results show that the product is hexagonal WO₃ phase with diameter of 25 nm and several ten micrometers long with growth in the c direction. The electrochemical properties were tested for rechargeable lithium batteries. The WO₃ NWs electrode exhibits a stability trend over the 30 cycle testing. Some long-term activation process is attributed to the WO₃ NWs electrode during charge/discharge reaction.

     

Silicon nanowires with and without carbon coating as anode materials for lithium-ion batteries

Silicon nanowires (Si NWs) with and without carbon coating were successfully prepared by combination of chemical vapor deposition and thermal evaporation method. The morphologies, structures, and compositions of these nanomaterials were characterized in detail. Furthermore, the electrochemical performances of uncoated and carbon-coated Si NWs as anode materials were also studied. It shows that the carbon-coated Si NWs electrode has higher capacity, better cycle stability, and rate capability than the uncoated materials. For example, it delivers 3,702 and 3,082 mAh g⁻¹ in the initial charge and discharge processes. When cycled between 0.02 and 2.0 V at a current density of 210 mA g⁻¹, it yields a high coulombic efficiency of 83.2%. The discharge capacity still remains around 2,150 mAh g⁻¹ after 30 cycles.     

Nanoparticle-coated separators for lithium-ion batteries with advanced electrochemical performance

We report a simple, scalable approach to improve the interfacial characteristics and, thereby, the performance of commonly used polyolefin based battery separators. The nanoparticle-coated separators are synthesized by first plasma treating the membrane in oxygen to create surface anchoring groups followed by immersion into a dispersion of positively charged SiO(2) nanoparticles. The process leads to nanoparticles electrostatically adsorbed not only onto the exterior of the surface but also inside the pores of the membrane. The thickness and depth of the coatings can be fine-tuned by controlling the ζ-potential of the nanoparticles. The membranes show improved wetting to common battery electrolytes such as propylene carbonate. Cells based on the nanoparticle-coated membranes are operable even in a simple mixture of EC/PC. In contrast, an identical cell based on the pristine, untreated membrane fails to be charged even after addition of a surfactant to improve electrolyte wetting. When evaluated in a Li-ion cell using an EC/PC/DEC/VC electrolyte mixture, the nanoparticle-coated separator retains 92% of its charge capacity after 100 cycles compared to 80 and 77% for the plasma only treated and pristine membrane, respectively.     

Reduced graphene oxide wrapped hollow molybdenum trioxide nanorod for high performance lithium-ion batteries

Reduced graphene oxide wrapped hollow molybdenum trioxide nanorods have been fabricated as a high performance anode material for lithium batteries.     

Polythiophene-coated nano-silicon composite anodes with enhanced performance for lithium-ion batteries

Herein, a new polythiophene-coated silicon composite anode material was prepared by in situ chemical oxidation polymerization method. The structure of this material was characterized by infrared spectroscopy, which proved that the oxidative polymerization of thiophene occurred mainly in α position. The polythiophene can provide the better electric contact between silicon particles. Therefore, the as-prepared Si/polythiophene composite electrodes achieve better cycling performance than the bare Si anode. The specific capacity of the composite electrode retains 478 mA h g^?1 after 50 cycles.     

Influence of graphene oxide on electrochemical performance of Si anode material for lithium-ion batteries

We have developed a Si/graphene oxide electrode synthesized via ultrasonication-stirring method under alkaline condition. Scanning electron microscopy(SEM), transmission electron microscope(TEM), EDS dot-mapping and high-resolution transmission electron microscopy(HRTEM) results show that Si particles are evenly dispersed on the graphene oxide sheets. The electrochemical performance was investigated by galvanostatic charge/discharge tests at room temperature. The results revealed that Si/graphene oxide electrode exhibited a high reversible capacity of 2825 mAh/g with a coulombic efficiency of 94.6%at 100 mA/g after 15 cycles and a capacity retention of 70.8% after 105 cycles at 4000 mA/g. These performance parameters show a great potential in the high-performance batteries application for portable electronics, electric vehicles and renewable energy storage.     

水热法制备不同形貌氧化镁及其抗菌性能研究

以盐湖氯化镁、碳酸钠、氨水等为原料,采用水热法制备了孔径分布在5nm~10nm之间,材料比表面积达到424.42m2/g的介孔氧化镁。通过X-射线衍射仪(XRD)、扫描电子显微镜(SEM)、同步热分析仪(TGDTA)以及抗菌性能测试等方法,探讨了反应时间、沉淀剂、分散剂和反应物浓度等因素对产物形貌和结构的影响。以大肠杆菌、金黄色葡萄球菌为测试菌株,用最小抑菌浓度(MIC)、24h抑菌效果图等方法研究了球状、片状和块状等不同形貌氧化镁的抗菌性能,建立了纳米氧化镁形貌与抗菌性能的关系。     

Mesoporous polymer-coated PAN beads for environmental applications: fabrication,characterisation and uranium adsorption studies

Adsorption of U(VI) and other heavy metals on millimetre sized polymer-coated polyacrylinitrile (PAN) beads was investigated. PAN was used as scaffolds for the polymer layer thus producing porous material of high surface area, improved mechanical strength and improved adsorption capabilities. Extensive U(VI) adsorption studies were undertaken and results modelled using different kinetic and equilibrium models. Parameters including thermodynamic parameters were evaluated. Sorbent capacities were assessed as 124, 16, and 33 mg g^?1 for PCP, SPP and Dowex at 60 °C respectively. U(VI) adsorption mechanism for these adsorbents was postulated. Recovered uranium may be used for production of cheap electricity.     

Surfactant-free synthesis of hyperbranched monoclinic bismuth vanadate and its applications in photocatalysis, gas sensing, and lithium-ion batteries

Hyperbranched monoclinic BiVO(4) (h-BiVO(4)) has been synthesized on a large scale and with good uniformity by a surfactant-free hydrothermal route. h-BiVO(4) consists of four trunks with branches distributed on opposite sides. From observation of the intermediates at an early stage of the reaction process, it can be seen that during formation h-BiVO(4) has different growth rates along the a, b, and c axes. Based on crystal structure analysis and experimental results, h-BiVO(4) shows preferential growth along the [100] direction, and subsequently, along the [010] and [001] directions. As-synthesized h-BiVO(4) exhibits excellent photocatalytic ability in the photodegradation reaction of an aqueous solution of RB under visible light. Electrochemical measurements predict that h-BiVO(4) possesses high sensitivity to formaldehyde and ethanol gases, favorable discharge capacity, and capacity retention, which indicate potential applications in the fields of sensing devices and lithium-ion batteries.     

Nanocrystalline cellulose-reinforced composite mats for lithium-ion batteries: electrochemical and thermomechanical performance

Nanocrystalline cellulose (NCC)-reinforced poly(vinylidenefluoride-co-hexafluoropropylene) (PVdF-HFP) composite mats have been prepared by electrospinning method. Polymer electrolytes formed by activating the composite mats with 1 M lithium bis(trifluoromethanesulfonyl)imide/1-butyl-3-methypyrrolidinium bis(trifluoromethanesulfonyl)imide electrolyte solution. The addition of 2 wt% NCC in PVdF-HFP improved the electrolyte retention and storage modulus of the separator by 63 and 15 %, respectively. The developed electrolyte demonstrated high value of ionic conductivity viz. 4?×?10^?4?S?cm^?1 at 30 °C. Linear scan voltammetry revealed a wide electrochemical stability of the composite mat separator up to 5 V (vs. Li⁺/Li). Cyclic voltammetry of the polymer electrolyte with a graphite electrode in 2.5 to 0 V (vs. Li⁺/Li) potential range showed a reversible intercalation/de-intercalation of Li⁺ ions in the graphite. No peaks were observed related to the reduction of the electrolyte on the anode.     

双金属离子调控型镍钴氧化物纳米片用于非对称超级电容器

通过水热-煅烧两步法制备了系列镍钴氧化物（NCO）纳米片。通过改变前驱体溶液中的镍、钴离子物质的量之比,进而调控NCO纳米片中的过渡金属离子比例。NCO纳米片的晶相、形貌和结构利用X射线衍射、扫描电子显微镜和X射线光电子能谱表征。此外,对NCO纳米片的电化学性能进行测试。结果表明,NCO-2（Ni_1.95Co₁O_x）纳米片在0.5 A·g^-1电流密度下,比电容为1 096.88 F·g^-1,且经过5 000次循环后具有78.26%的循环稳定性。以NCO-2为正极、活性碳为负极构成的非对称超级电容器,在功率密度为576 W·kg^-1时,能量密度为57.70 Wh·kg^-1。     

双金属离子调控型镍钴氧化物纳米片用于非对称超级电容器

通过水热-煅烧两步法制备了系列镍钴氧化物(NCO)纳米片。通过改变前驱体溶液中的镍、钴离子物质的量之比，进而调控NCO纳米片中的过渡金属离子比例。NCO纳米片的晶相、形貌和结构利用X射线衍射、扫描电子显微镜和X射线光电子能谱表征。此外，对NCO纳米片的电化学性能进行测试。结果表明，NCO-2(Ni_1.95Co₁O_x)纳米片在0.5 A·g^-1电流密度下，比电容为1 096.88 F·g^-1，且经过5 000次循环后具有78.26%的循环稳定性。以NCO-2为正极、活性碳为负极构成的非对称超级电容器，在功率密度为576 W·kg^-1时，能量密度为57.70 Wh·kg^-1。     

Iron sulfide-embedded carbon microsphere anode material with high-rate performance for lithium-ion batteries

Iron sulfide-embedded carbon microspheres were prepared via a solvothermal process and show high specific capacity and excellent high-rate performance as anode material for lithium-ion batteries.     

State-of-the-art anodes of potassium-ion batteries: synthesis,chemistry, and applications

The growing demand for green energy has fueled the exploration of sustainable and eco-friendly energy storage systems. To date, the primary focus has been solely on the enhancement of lithium-ion battery (LIB) technologies. Recently, the increasing demand and uneven distribution of lithium resources have prompted extensive attention toward the development of other advanced battery systems. As a promising alternative to LIBs, potassium-ion batteries (KIBs) have attracted considerable interest over the past years owing to their resource abundance, low cost, and high working voltage. Capitalizing on the significant research and technological advancements of LIBs, KIBs have undergone rapid development, especially the anode component, and diverse synthesis techniques, potassiation chemistry, and energy storage applications have been systematically investigated and proposed. In this review, the necessity of exploring superior anode materials is highlighted, and representative KIB anodes as well as various structural construction approaches are summarized. Furthermore, critical issues, challenges, and perspectives of KIB anodes are meticulously organized and presented. With a strengthened understanding of the associated potassiation chemistry, the composition and microstructural modification of KIB anodes could be significantly improved.

State-of-the-art tendency, present critical issues and future opportunities of anode active materials in potassium ion batteries are systematically summarized.     

Effects of vanadium oxide coating on the performance of LiFePO4/C cathode for lithium-ion batteries

Journal of Solid State Electrochemistry - LiFePO4 cathode material is considered as prospective materials for lithium-ion batteries and attracted great interest because of excellent cyclic...