首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
Nickel foam-supported porous NiO film was prepared by a chemical bath deposition technique, and the NiO/polyaniline (PANI) film was obtained by depositing the PANI layer on the surface of the NiO film. The NiO film was constructed by NiO nanoflakes, and after the deposition of PANI, these nanoflakes were coated by PANI. As an anode for lithium ion batteries, the NiO/PANI film exhibits weaker polarization as compared to the NiO film. The specific capacity after 50 cycles for NiO/PANI film is 520 mAh g−1 at 1 C, higher than that of NiO film (440 mAh g−1). The improvement of these properties is attributed to the enhanced electrical conduction and film stability of the electrode with PANI.  相似文献   

2.
A new concept for fabricating novel triple-layered nanorod array electrodes made of coaxial Cu-Si@C arrays has been developed. They exhibit excellent electrochemical performance resulting from peculiar new sandwiched architectures: robust Cu nanopillar cores/amorphous Si layers/elastic carbon shells.  相似文献   

3.
《Solid State Sciences》2012,14(9):1251-1255
Chemical manganese dioxide (CMD) is synthesized by the SEDEMA process and adopted as a precursor for lithium manganese oxide with a spinel structure (LMO). LMO is also prepared from electrolytic manganese dioxide (EMD) as a reference for comparison. X-ray diffraction (XRD) shows that CMD is composed of γ-MnO2, and scanning electron microscopy (SEM) with transmission electron microscopy (TEM) shows that the nanorods cover a spherical core with a diameter < 1 μm. The LMO prepared from CMD shows a much better rate capability and cycle life performance than that from EMD at high temperatures and high current densities. The excellent electrochemical performance is attributed to the structural stability during charge and discharge and the morphology of the LMO, a loose aggregation of the octahedral particles with a uniform size (<1 μm) and shape, which originated from that of CMD.  相似文献   

4.
TiO2 array film fabricated by potentiostatic anodization of titanium is characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and charge–discharge measurements. The XRD results indicated that the TiO2 array is amorphous, and after calcination at 500 °C, it has the anatase form. The pore size and wall thickness of TiO2 nanotube arrays synthesized at different anodization voltages are highly dependent on the applied voltage. The electrochemical performance of the prepared TiO2 nanotube array as an electrode material for lithium batteries was evaluated by galvanostatic charge–discharge measurement. The sample prepared at 20 V shows good cyclability but low discharge capacity of 180 mA h cm−3, while the sample prepared at 80 V has the highest discharge capacity of 340 mA h cm−3.  相似文献   

5.
Highly ordered mesoporous Cr(2)O(3) materials with high specific surface area and narrow pore size distribution were successfully prepared by a vacuum assisted impregnation method. Both 2-dimensional hexagonal and 3-dimensional cubic Cr(2)O(3) mesoporous replicas from SBA-15 and KIT-6 templates exhibit enhanced performance for gas sensors and lithium ion batteries, compared to the bulk Cr(2)O(3) counterpart.  相似文献   

6.
Lithium metal is one of the most promising anode materials for next-generation electrochemical energy storage due to low electrochemical potential and high spec...  相似文献   

7.
Nano-sized nickel ferrite (NiFe2O4) was prepared by hydrothermal method at low temperature. The crystalline phase, morphology and specific surface area (BET) of the resultant samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM) and nitrogen physical adsorption, respectively. The particle sizes of the resulting NiFe2O4 samples were in the range of 5–15 nm. The electrochemical performance of NiFe2O4 nanoparticles as the anodic material in lithium ion batteries was tested. It was found that the first discharge capacity of the anode made from NiFe2O4 nanoparticles could reach a very high value of 1314 mAh g−1, while the discharge capacity decreased to 790.8 mAh g−1 and 709.0 mAh g−1 at a current density of 0.2 mA cm−2 after 2 and 3 cycles, respectively. The BET surface area is up to 111.4 m2 g−1. The reaction mechanism between lithium and nickel ferrite was also discussed based on the results of cycle voltammetry (CV) experiments.  相似文献   

8.
Nanocrystalline MnO thin film has been prepared by a pulsed laser deposition (PLD) method. The reversible lithium storage capacity of the MnO thin film electrodes at 0.125C is over 472 mAh g?1 (3484 mAh cm?3) and can be retained more than 90% after 25 cycles. At a rate of 6C, 55% value of the capacity at 0.125C rate can be obtained for both charge and discharge. As-prepared MnO thin film electrodes show the lowest values of overpotential for both charge and discharge among transition metal oxides. All these performances make MnO a promising high capacity anode material for Li-ion batteries.  相似文献   

9.
A B2O3-doped SnO2 thin film was prepared by a novel experimental procedure combining the electrodeposition and the hydrothermal treatment, and its structure and electrochemical properties were investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) analysis, energy dispersive X-ray (EDX) spectroscopy and galvanostatic charge–discharge tests. It was found that the as-prepared modified SnO2 film shows a porous network structure with large specific surface area and high crystallinity. The results of electrochemical tests showed that the modified SnO2 electrode presents the largest reversible capacity of 676 mAh g?1 at the fourth cycle, close to the theoretical capacity of SnO2 (790 mAh g?1); and it still delivers a reversible Li storage capacity of 524 mAh g?1 after 50 cycles. The reasons that the modified SnO2 film electrode shows excellent electrochemical properties were also discussed.  相似文献   

10.
An ordered mesoporous WO(3-X) with high electrical conductivity (m-WO(3-X)) was prepared and evaluated as an anode material for lithium ion batteries (LIBs). Ordered mesoporous tungsten trioxide (m-WO(3)) with an identical pore structure to that of m-WO(3-X) and bulk WO(3-X) (b-WO(3-X)) was prepared for the comparison purpose. An m-WO(3-X) electrode exhibited a high reversible capacity (748 mAh g(-1), 6.5 Li/W) and a high volumetric capacity (~1500 mAh cm(-3)), which is comparable to the Li metal itself (ca. 2000 mAh cm(-3)). Also, an improved rate capability and a good cyclability were observed in the m-WO(3-X) electrode when compared with m-WO(3) and b-WO(3-X) electrodes. From electrochemical impedance spectroscopy (EIS) analysis, the advanced anode performance of the m-WO(3-X) electrode was probably attributed to large ordered mesopores and a high electrical conductivity. Differential scanning calorimetry (DSC) result displayed that the safety of m-WO(3-X) was more improved than those of graphite and Si anode materials.  相似文献   

11.
Thin films of pure SnO2, of the Sn/Li2O layered structure, and of Sn/Li2O were fabricated by sputtering method, while a `lithium-reacted tin oxide thin film' was assembled by the evaporation of lithium metal onto a SnO2 thin film. Film structure and charge/discharge characteristics were compared. The lithium-reacted tin oxide thin film, the Sn/Li2O layered structure, and the Sn/Li2O co-sputtered thin films did not show any irreversible side reactions of forming Li2O and metallic Sn near 0.8 V vs Li/Li+. The initial charge retention of the Sn/Li2O layered structure and Sn/Li2O co-sputtered thin films was about 50% and a similar value was found for the lithium-reacted tin oxide thin film (more than 60%). Sn/Li2O layered structure and Sn/Li2O co-sputtered thin films showed better cycling behavior over 500 cycles than the pure SnO2 and lithium-reacted tin oxide thin film in the cut-off range from 1.2 to 0 V vs Li/Li+.  相似文献   

12.
Porous carbons with a high surface area have been prepared from rice straw. The hierarchical porous network with large macroporous channels and micropores within the channel walls enable the porous carbons to provide the pathways for easy accessibility of electrolytes and fast transportation of lithium ions. These porous carbons which show a particular large reversible capacity are proved to be promising anode materials for high-rate and high-capacity lithium ion batteries.  相似文献   

13.
We have prepared a high-density polyaniline(PANI) paste(50 mg/m L), with similar physical properties to those of paints or pigments. The synthesis of PANI is confirmed by Fourier transform infrared(FT-IR) spectroscopy. The morphologies of PANI, doped PANI, and doped PANI paste are confirmed by scanning electron microscopy(SEM). Particles of doped PANI paste are approximately 40–50 nm in diameter, with a uniform and cubic shape. The electrochemical performances of doped PANI paste using both liquid and solid polymer electrolytes have been measured by galvanostatic charge and discharge process. The cell fabricated with doped PANI paste and the solid polymer electrolyte exhibits a discharge capacity of ~87 μAh/cm2(64.0 m Ah/g) at the second cycle and~67 μAh/cm2(50.1 m Ah/g) at the 100 th cycle.  相似文献   

14.
SnS particles with sizes of 5.0–6.5 nm were prepared by a facile method. Resorcinol–formaldehyde sol with addition of the as-prepared SnS nanoparticles was spin-coated on a copper foil to prepare net-like SnS/C composite thin-film electrode for lithium ion batteries after carbonization at 650 °C. The SnS/C nanocomposite thin-film electrode showed preferable first coulombic efficiency and excellent cycling stability. The discharge and charge capacities were respectively 542.3 and 531.3 mAh/g after 40 cycles. The attractive electrochemical performances were mainly ascribed to the ultra fine particle, which showed no evident aggregation in high-resolution TEM image, and the effects of 3-dimensional net-like carbon structure, which uniformly surrounded the SnS nanoparticles to guarantee the contact, acted as a buffer matrix to alleviate the volume expansion of Li–Sn alloy and provided enough paths for electrolyte to reach SnS active material during discharge–charge process.  相似文献   

15.
The Si/SiO nanocomposite was synthesized by a sol–gel method in combination with a following heat-treatment process. It was analyzed by X-ray diffraction (XRD), transmission electron microscopy (TEM), cyclic voltammetry (CV) and capacity measurement as anode material for lithium ion battery. Si nanoparticles were coated with SiO and a core-shell structured nanocomposite was formed. The core-shell Si/SiO nanocomposite displays better reversibility of lithium insertion/extraction and higher coulomb efficiency than virginal Si nanoparticles. The SiO shell envelops the Si nanoparticles to suppress the aggregation of the nanoparticles during cycling. As a result, the core-shell Si/SiO nanocomposite exhibits better capacity retention than virginal Si nanoparticles, indicating that this is a promising approach to improve the electrochemical performance of nano anode materials for lithium ion battery.  相似文献   

16.
Platelike CoO/carbon nanofiber (CNF) composite materials with porous structures are synthesized from the thermal decomposition and recrystallization of β-Co(OH)2/CNF precursor without the need for a template or structure-directing agent. As negative electrode materials for lithium-ion batteries, the platelike CoO/CNF composite delivers a high reversible capacity of 700 mAh g−1 for a life extending over hundreds of cycles at a constant current density of 200 mA g−1. More importantly, the composite electrode shows significantly improved rate capability and electrochemical reversibility. Even at a current of 2 C, the platelike CoO/CNF composite maintain a capacity of 580 mAh g−1 after 50 discharge/charge cycles. The improved cycling stability and rate capability of the CoO/CNF composite electrodes may be attributed to synergistic effect of the porous structural stability and improved conductivity through CNF connection.  相似文献   

17.
Highly ordered three-dimensional macroporous 3DOM FePO4 cathode material was prepared by using a colloidal crystal template. The effects of the annealing temperature on the morphology changes and the electrochemical properties of the composite were investigated. The 3DOM FePO4 prepared at 400 °C shows the excellent cycling stability and good rate capability as a cathode for lithium–ion batteries.  相似文献   

18.
Nanocrystalline nickel molybdate (NiMoO(4)) thin film electrodes with a 3D honeycomb structure of uniform 17 nm diameter pores were successfully produced through facile polymer templating strategies. These novel sol-gel type materials exhibit enhanced lithium ion storage capabilities, and thus show promise for battery applications.  相似文献   

19.
Synthesis strategies, nanostructures, and different electrochemical performances are prominent features of rechargeable batteries. Three types Li2MSiO4 cathode metarials for lithium ion batteries:Li2FeSiO4, Li2MnSiO4, and Li2CoSiO4 are scientifically discussed, and the comprehensive summaries and evaluations are given in this review.  相似文献   

20.
The structure and anodic performance of boron-doped and undoped mesocarbon microbeads (MCMBs) have been comparatively studied and the results obtained by XPS, XRD, SEM, Raman spectroscopy and electrochemical measurements are discussed. It is found that boron doping introduces a depressed d 002 spacing and the larger amount of "unorganized carbon", which induces vacancy formation in the graphite planes and leads to a quite different morphology from that of the undoped material. Electrochemical charge/discharge cycle tests indicated that after boron doping the lithium intercalation was carried through at a somewhat higher potential, being attended by greater irreversible capacity loss. Electronic Publication  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号