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1.
S/Li4Ti5O12 cathode with high lithium ionic conductivity was prepared for Li-S battery. Herein, nano Li4Ti5O12 is used as sulfur host and fast Li+ conductor, which can adsorb effectively polysulfides and improve remarkably Li+ diffusion coefficient in sulfur cathode. At 0.5 C, S/Li4Ti5O12 cathode has a stable discharge capacity of 616 mAh g?1 at the 700th cycle and a capacity loss per cycle of 0.0196% from the second to the 700th cycle, but the corresponding values of S/C cathode are 437 mAh g?1 and 0.0598%. Even at 2 C, the capacity loss per cycle of S/Li4Ti5O12 cathode is only 0.0273% from the second to the 700th cycle. The results indicate that Li4Ti5O12 as the sulfur host plays a key role on the high performance of Li-S battery due to reducing the shuttle effect and enhancing lithium ionic conductivity.  相似文献   

2.
Li2Mn4O9 and molybdenum-doped Li2Mn4O9 have been prepared by simple solid-state method. Molybdenum is used as a dopant since it is resistant to both corrosion and high-temperature creep deformation. The structural, morphological, and electrical performances of the samples have been analyzed. The material exhibits a cubic structure with the fd3m space group. Using EDAX, the chemical compositions of the samples have been identified. The dc electrical conductivity of the Mo-doped (LM2) sample is found to be increased to 7.44?×?10?6 S cm?1 at 393 K. The enhanced electrical property of the molybdenum-doped Li2Mn4O9 reveals it as a feasible cathode material for rechargeable Li-ion batteries.  相似文献   

3.
A comparison of electrochemical performance between LiFe0.4Mn0.595Cr0.005PO4/C and LiMnPO4/C cathode materials was conducted in this paper. The cathode samples were synthesized by a nano-milling-assisted solid-state process using caramel as carbon sources. The prepared samples were investigated by XRD, SEM, TEM, energy-dispersive X-ray spectroscopy (EDAX), powder conductivity test (PCT), carbon-sulfur analysis, electrochemical impedance spectroscopy (EIS), and galvanostatic charge-discharge cycling. The results showed that LiFe0.4Mn0.595Cr0.005PO4/C exhibited high specific capacity and high energy density. The initial discharge capacity of LiFe0.4Mn0.595Cr0.005PO4/C was 163.6 mAh g?1 at 0.1C (1C = 160 mA g?1), compared to 112.3 mAh g?1 for LiMnPO4/C. Moreover, the Fe/Cr-substituted sample showed good cycle stability and rate performance. The capacity retention of LiFe0.4Mn0.595Cr0.005PO4/C was 98.84 % over 100 charge-discharge cycles, while it was only 86.64 % for the pristine LiMnPO4/C. These results indicated that Fe/Cr substitution enhanced the electronic conductivity for the prepared sample and facilitated the Li+ diffusion in the structure. Furthermore, LiFe0.4Mn0.595Cr0.005PO4/C composite presented high energy density (606 Wh kg?1) and high power density (574 W kg?1), thus suggested great potential application in lithium ion batteries (LIBs).  相似文献   

4.
In this work, a graphene-decorated Li2S cathode has been prepared via spray drying method using Li2SO4, graphene oxide and sucrose as raw materials. During spray drying, sucrose melts and embeds Li2SO4 when Li2SO4 were sprayed out with graphene oxide and sucrose, and becomes sphere particles. The as-prepared Li2S composite was received after a heat treatment under nitrogen atmosphere. X-ray diffraction patterns confirm the cubic structure of Li2S and scanning electron microscope images reveal that Li2S and carbon components stay in sphere structure with diameter around 20 μm. The sphere Li2S composite shows enhanced performance when acts as cathode. Under current density of 100 mA g?1, a specific discharge capacity of 778 mAh g?1 has been achieved and the battery cycled over 60 rounds. Furtherly, the sphere composite was coupled with silicon/graphite anode to construct full cell system, suggesting large possibility to work with the current lithium-ion battery anodes.  相似文献   

5.
Advanced Li-air battery architecture demands a high Li+ conductive solid electrolyte membrane that is electrochemically stable against metallic lithium and aqueous electrolyte. In this work, an investigation has been carried out on the microstructure, Li+ conduction behaviour and structural stability of Li7La3-x Y x Zr2O12 (x = 0.125, 0.25 and 0.50) prepared by conventional solid-state reaction technique. The phase analysis of Li7La3-x Y x Zr2O12 (x = 0.125, 0.25 and 0.50) sintered at 1200 °C by powder X-ray diffraction (PXRD) and Raman confirms the formation of high Li+ conductive cubic phase (\( Ia\overline{3}d \)) lithium garnets. Among the investigated lithium garnets, Li7La2.75Y0.25Zr2O12 sintered at 1200 °C exhibits a maximized room temperature total (bulk + grain boundary) Li+ conductivity of 3.21 × 10?4 S cm?1 along with improved relative density of 96 %. The preliminary investigation on the structural stability of Li7La2.75Y0.25Zr2O12 in the solutions of 1 M LiCl, dist. H2O and 1 M LiOH at 30 °C/50 °C indicates that the Li7La2.75Y0.25Zr2O12 is relatively stable against 1 M LiCl and dist. H2O. Further electrochemical investigation is essential for practical application of Li7La2.75Y0.25Zr2O12 as protective solid electrolyte membrane in aqueous Li-air battery.  相似文献   

6.
The layered Li1.2Mn0.54Ni0.13Co0.13O2 lithium-rich manganese-based solid solution cathode material has been synthesized by a simple solid-state method. The as-prepared material has a typical layered structure with R-3m and C2/m space group. The synthesized Li1.2Mn0.54Ni0.13Co0.13O2 has an irregular shape with the size range from 200 to 500 nm, and the primary particle of Li1.2Mn0.54Ni0.13Co0.13O2 has regular sphere morphology with a diameter of 320 nm. Electrochemical performances also have been investigated. The results show that the cathode material Li1.2Mn0.54Ni0.13Co0.13O2 prepared at 900 °C for 12 h has a good electrochemical performance, which can deliver a high initial discharge capacity of 233.5, 214.2, 199.3, and 168.1 mAh g?1 at 0.1, 0.2, 0.5, and 1 C, respectively. After 50 cycles, the capacity retains 178.0, 166.3, 162.1, and 155.9 mAh g?1 at 0.1, 0.2, 0.5, and 1 C, respectively. The results indicate that the simple method has a great potential in synthesizing manganese-based cathode materials for Li-ion batteries.  相似文献   

7.
Li4Ti5O12/Cu2O composite was prepared by ball milling Li4Ti5O12 and Cu2O with further heat treatment. The structure and electrochemical performance of the composite were investigated via X-ray diffraction, scanning electron microscopy, energy-dispersive spectroscopy, cyclic voltammetry, electrochemical impedance spectroscopy, and galvanostatic charge–discharge tests. Li4Ti5O12/Cu2O composite exhibited much better rate capability and capacity performance than pristine Li4Ti5O12. The discharge capacity of the composite at 2 C rate reached up to 122.4 mAh g?1 after 300 cycles with capacity retention of 91.3 %, which was significantly higher than that of the pristine Li4Ti5O12 (89.6 mAh g?1). The improvement can be ascribed to the Cu2O modification. In addition, Cu2O modification plays an important role in reducing the total resistance of the cell, which has been demonstrated by the electrochemical impedance spectroscopy analysis.  相似文献   

8.
The precursor of plate-like Li3PS4 solid electrolyte (75Li2S?25P2S5, SE (LS)), about 3 μm in length, 500 nm in width, and 100–200 nm in thickness, was successfully prepared from Li2S and P2S5 using ethyl propionate (EP) as a synthetic medium via liquid-phase shaking. Upon evacuating at 170 °C, the precursor decomposed to SE (LS), which exhibited ionic conductivity of about 2.0 × 10?4 Scm?1 at room temperature. SEM observation revealed that the SE (LS) thus obtained had plate-like morphology with dimension of 3 μm in length, 500 nm in width, and 100–200 nm in thickness. Owing to the nanosized SE (LS), an all-solid-state half-cell using composite anode consisting of 90 wt% LiNi1/3Mn1/3Co1/3O2 (NMC) and 10 wt% SE (LS) delivered a high capacity up to 130 mAhg?1(NMC) at the first discharge.  相似文献   

9.
To suppress the capacity fade of Li-rich Li1.2Ni0.13Co0.13Mn0.54O2 material as cathode materials for lithium-ion battery, we introduce a LiF coating layer on the surface to improve the cycling performance of Li1.2Ni0.13Co0.13Mn0.54O2 material. The modified sample shows a capacity of 163.2 mAh g?1 with a capacity retention of 95% after 100 cycles at a current density of 250 mA g?1, while the pristine sample only delivers a capacity of 129.9 mAh g?1 with a capacity retention of 82%. Compared with the pristine material, the LiF-modified sample exhibits an obvious enhancement in the electrochemical performance, which will be very beneficial for this material to be commercialized on the new energy vehicles and other related areas.  相似文献   

10.
In order to improve the rate capability of Li4Ti5O12, Ti4O7 powder was successfully fabricated by improved hydrogen reduction method, then a dual-phase composite Li4Ti5O12/Ti4O7 has been synthesized as anode material for lithium-ion batteries. It is found that the Li4Ti5O12/Ti4O7 composite shows higher reversible capacity and better rate capability compared to Li4Ti5O12. According to the charge-discharge tests, the Li4Ti5O12/Ti4O7 composite exhibits excellent rate capability of 172.3 mAh g?1 at 0.2 C, which is close to the theoretical value of the spinel Li4Ti5O12. More impressively, the reversible capacity of Li4Ti5O12/Ti4O7 composite is 103.1 mAh g?1 at the current density of 20 C after 100th cycles, and it maintains 84.8% of the initial discharge capacity, whereas that of the bare spinel Li4Ti5O12 is only 22.3 mAh g?1 with a capacity retention of 31.1%. The results indicate that Li4Ti5O12/Ti4O7 composite could be a promising anode material with relative high capacity and good rate capability for lithium-ion batteries.  相似文献   

11.
We describe in this paper the synthesis and the characterization of Li4Ti5O12-reduced graphene oxide (LTO-RGO) composite and demonstrate their use as hybrid supercapacitor, which is consist of an LTO negative electrode and activate carbon (AC) positive electrode. The LTO-RGO composites were synthesized using a simple, one-step process, in which lithium sources and titanium sources were dissolved in a graphene oxide (GO) suspension and then thermal treated in N2. The lithium-ion battery with LTO-RGO composite anode electrode revealed higher discharge capacity (167 mAh g?1 at 0.2 C) and better capacity retention (67%) than the one with pure LTO. Meanwhile, compared with the AC//LTO supercapacitor, the AC//LTO-RGO hybrid supercapacitor exhibits higher energy density and power density. Results show that the LTO-RGO composite is a very promising anode material for hybrid supercapacitor.  相似文献   

12.
Lithium-rich cathode material Li[Li0.2Ni0.13Co0.13Mn0.54]O2 doped with trace Mo is successfully synthesized by a sol-gel method. The X-ray diffraction patterns show that trace Mo substitution increases the inter-layer space of the material, of which is benefiting to lithium ion insertion/extraction among the electrode materials. The (CV) tests demonstrate the decrease of polarization, and on the other hand, the lithium ion diffusion coefficient (D Li) of the modified material turns out to be larger, which indicates a faster electrochemical process. As a result, the Mo doped material possesses high rate performance and good cycling stability, and the initial discharge capacity reaches 149.3 mAh g?1 at a current density of 5.0 °C, and the residual capacity is 144.0 mAh g?1 after 50 cycles with capacity retention of 96.5 % in the potential range of 2.0–4.8 V at room temperature.  相似文献   

13.
Li1,3Ti0,7Al0,3(PO4)3 (LATP) powder was obtained by a conventional melt-quenching method and consolidated by field-assisted sintering technology (FAST) at different temperatures. Using this technique, the samples could be sintered to relative densities in the range of 93 to 99 % depending on the sintering conditions. Ionic and thermal conductivity were measured and the results are discussed under consideration of XRD and SEM analyses. Thermal conductivity values of 2 W/mK and ionic conductivities of 4?×?10?4 Scm?1 at room temperature were obtained using relatively large particles and a sintering temperature of 1000 °C at an applied uniaxial pressure of 50 MPa.  相似文献   

14.
Shuai Li  Hongbo Liu  Yuxi Chen 《Ionics》2016,22(12):2291-2298
Carbon-coated layered Li1.20Ti0.44Cr0.36O2/C and pristine Li1.20Ti0.44Cr0.36O2 cathode materials have been synthesized through a sol–gel method followed by high-temperature calcination. Their electrochemical performances have been evaluated, which indicate that the Li1.20Ti0.44Cr0.36O2/C exhibits much higher cyclic stability and capacity than the pristine one. The initial delithiation capacity of the Li1.20Ti0.44Cr0.36O2/C can reach 217.1 mAh g?1. The reversible capacity retention is 94 % after 100 cycles at current density of 23 mA g?1. Ex situ X-ray diffraction and electrochemistry impedance spectroscopy coupled with impedance fitting have been employed to reveal evolution of the crystal structure and the electrochemical kinetics of the Li1.20Ti0.44Cr0.36O2/C with delithiation/lithiation cycling. The results indicate that the cation layers of the Li1.20Ti0.44Cr0.36O2/C experience order to disorder transition. The abrupt delithiation capacity fading and potential drop after the initial cycle are resulted from the order to disorder transition accompanying with steep increase of the charge transfer resistance and decrease of the exchange current density and the Li-ion diffusion coefficient simultaneously.  相似文献   

15.
The Li3V2(PO4)3/C (LVP/C) cathode materials for lithium-ion batteries were synthesized via ethylene glycol-assisted solvothermal method. The phase composition, phase transition temperature, morphology, and fined microstructure were studied using X-ray diffraction (XRD), differential thermal analyzer (DTA), scanning electron microscope (SEM), and transmission electron microscope (TEM), respectively. The electrochemical properties, impedance, and electrical conductivity of LVP/C cathode materials were tested by channel battery analyzer, the electrochemical workstation, and the Hall test system, respectively. The results shown that the appropriate amount of water added to ethylene glycol solvent contributes to the synthesis of pure phase LVP. The LVP10/C cathode material can exhibit discharge capacities of 128, 126, 126, 123, 124, and 114 mAh g?1 at 0.1, 0.5, 2, 5, 10, and 20 C in the voltage range of 3.0–4.3 V, respectively. Meanwhile, it shows also a stable cycling performance with the capacity retention of 89.6% after 180 cycles at 20 C.  相似文献   

16.
Ni sintering at high temperature (~ 800 °C) operation drastically degrades the performance of Ni-yttria-stabilized zirconia (YSZ) anode in solid oxide fuel cell (SOFC). Mixed ionic and electronic conductive oxides such as CeO2 and Nb2O5 enhance the dispersion of Ni, CeO2 enhances the redox behavior and promotes charge transfer reactions, and Nb2O5 increases the triple phase boundary. In the present work, anode-supported SOFC is fabricated and tested in H2 fuel at 800 °C. YSZ and lanthanum strontium manganite (LSM)-YSZ are used as the electrolyte and composite cathode with NiO-YSZ, CeO2-NiO-YSZ, and Nb2O5-NiO-YSZ as an anode. The peak power density obtained for the cell with 10% CeO2–30% NiO-YSZ anode at the 5 and 25 h of operation is 330 and 290 mW cm?2 which is higher than that for 40% NiO-YSZ anode (275 mW cm?2 at 5 h). The peak power density obtained for the cell with 10% Nb2O5–30% NiO-YSZ anode at the 5 and 25 h of operation is 301 and 285 mW cm?2 which is higher than that for 40% NiO-YSZ anode (275 mW cm?2 at 5 h). Physical characterization has been carried to study morphology, elemental analysis, particle size, and phase formation of the fabricated anode before and after cell operation to correlate the cell performance.  相似文献   

17.
In order to establish the mechanism and to determine the parameters of lithium transport in electrodes based on lithium-vanadium phosphate (Li3V2(PO4)3), the kinetic model was designed and experimentally tested for joint analysis of electrochemical impedance (EIS), cyclic voltammetry (CV), pulse chronoamperometry (PITT), and chronopotentiometry (GITT) data. It comprises the stages of sequential lithium-ion transfer in the surface layer and the bulk of electrode material’s particles, including accumulation of lithium in the bulk. Transfer processes at both sites are of diffusion nature and differ significantly, both by temporal (characteristic time, τ) and kinetic (diffusion coefficient, D) constants. PITT data analysis provided the following D values for the predominantly lithiated and delithiated forms of the intercalation material: 10?9 and 3 × 10?10 cm2 s?1, respectively, for transfer in the bulk and 10?12 cm2 s?1 for transfer in the thin surface layer of material’s particles. D values extracted from GITT data are in consistency with those obtained from PITT: 3.5–5.8 × 10?10 and 0.9–5 × 10?10 cm2 s?1 (for the current and currentless mode, respectively). The D values obtained from EIS data were 5.5 × 10?10 cm2 s?1 for lithiated (at a potential of 3.5 V) and 2.3 × 10?9 cm2 s?1 for delithiated (at a potential 4.1 V) forms. CV evaluation gave close results: 3 × 10?11 cm2 s?1 for anodic and 3.4 × 10?11 cm2 s?1 for cathodic processes, respectively. The use of complex experimental measurement procedure for combined application of the EIS, PITT, and GITT methods allowed to obtain thermodynamic E,c dependence of Li3V2(PO4)3 electrode, which is not affected by polarization and heterogeneity of lithium concentration in the intercalate.  相似文献   

18.
Nanocrystalline Li2TiO3 was successfully synthesized using solid-state reaction method. The microstructural and electrochemical properties of the prepared material are systematically characterized. The X-ray diffraction pattern of the prepared material exhibits predominant (002) orientation related to the monoclinic structure with C2/c space group. HRTEM images and SAED analysis reveal the well-developed nanostructured particles with average size of ~40 nm. The electrochemical properties of the prepared sample are carried out using cyclic voltammetry (CV) and chronopotentiometry (CP) using Pt//Li2TiO3 cell in 1 mol L?1 Li2SO4 aqueous electrolyte. The Li2TiO3 electrode exhibits a specific discharge capacity of 122 mAh g?1; it can be used as anode in Li battery within the potential window 0.0–1.0 V, while investigated as a supercapacitor electrode, it delivers a specific capacitance of 317 F g?1 at a current density of 1 mA g?1 within the potential range ?0.4 to +0.4 V. The demonstration of both anodic and supercapacitor behavior concludes that the nanocrystalline Li2TiO3 is a suitable electrode material for supercapattery application.  相似文献   

19.
The graphene nanoflakes and olivine-type LiFe0.97Ni0.03PO4/C (LFNP3/C) samples have been synthesized as anode and cathode materials, respectively. Physicochemical characterization of the graphene nanoflakes and LFNP3/C material were studied using X-ray diffraction (XRD) and scanning electron microscope (SEM). The XRD patterns reveal the formation of the pure phase of both the synthesized samples. SEM micrographs disclose the formation of spherically shaped nanosized particles for LFNP3/C while graphene shows flake-type morphology. CR2032 half and full coin cells were assembled for electrochemical testing of the synthesized samples. Cyclic voltammetry (CV) results indicate that the graphene-based half-cells, i.e., GN1H and GN2H, possess reduction peak/plateau around 0.17 V while LFNP3/C cathode shows discharging voltage plateau at 3.4 V vs. Li/Li+. The discharge capacities were found to be 700, 900, and 153 mAhg?1 for GN1H, GN2H, and LFNP3/C half-cells vs. Li/Li+, respectively. Among full cells, LFPGN1F with γ = 0.75 (mass/capacity balancing factor) shows better charging/discharging profile at each C-rate as compared to LFPGN2F with γ = 0.55. LFPGN1F delivered an initial discharge capacity of around 154 mAhg?1 at 0.1C and even at a high discharge rate of 1C, it retained ~97% of the discharge capacity as compared to the initial cycle at the same rate.  相似文献   

20.
Inferior rate capability is a big challenge for LiTi2(PO4)3 anode for aqueous lithium-ion batteries. Herein, to address such issue, we synthesized a high-performance LiTi2(PO4)3/carbon/carbon nanotube (LTP/C/CNT) composite by virtue of high-quality carbon coating and incorporation of good conductive network. The as-prepared LTP/C/CNT composite exhibits excellent rate performance with discharge capacity of 80.1 and 59.1 mAh g?1 at 10 C and 20 C (based on the mass of anode, 1 C = 150 mA g?1), much larger than that of the LTP/C composite (53.4 mAh g?1 at 10 C, and 31.7 mAh g?1 at 20 C). LTP/C/CNT also demonstrates outstanding cycling stability with capacity retention of 83.3 % after 1000 cycles at 5 C, superior to LTP/C without incorporation of CNTs (60.1 %). As verified, the excellent electrochemical performance of the LTP/C/CNT composite is attributed to the enhanced electrical conductivity, rapid charge transfer, and Li-ion diffusion because of the incorporation of CNTs.  相似文献   

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