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1.
《Ceramics International》2017,43(8):6554-6562
In order to improve the electrochemical performance of lithium titanium oxide, Li4Ti5O12 (LTO), for the use in the lithium-ion capacitors (LICs) application, LTO/graphene composites were synthesized through a solid state reaction. The composite exhibited an interwoven structure with LTO particles dispersed into graphene nanosheets network rather than an agglomerated state pristine LTO particles. It was found that there is an optimum percentage of graphene additives for the formation of pure LTO phase during the solid state synthesis of LTO/graphene composite. The effect of graphene nanosheets addition on electrochemical performance of LTO was investigated by a systemic characterization of galvanostatic cycling in lithium and lithium-ion cell configuration. The optimized composite exhibited a decreased polarization upon cycling and delivered a specific capacity of 173 mA h g−1 at 0.1 C and a well maintained capacity of 65 mA h g−1 even at 20 C. The energy density of 14 Wh kg−1 at a power density of 2700 W kg−1 was exhibited by a LIC full cell with a balanced mass ratio of anode to cathode along with a superior capacitance retention of 97% after 3000 cycles at a current density of 0.4 A g−1. This boost in reversible capacity, rate capability and cycling performance was attributed to a synergistic effect of graphene nanosheets, which provided a short lithium ion diffusion path as well as facile electron conduction channels.  相似文献   

2.
Lithium-ion capacitors (LICs) composed of battery-type anodes with large energy densities and capacitor-type cathodes with high power densities are considered as appealing energy-storage devices. Here, a LIC with good performance is constructed using active carbon (AC) as the cathode and Li1.95La0.05ZnTi3O8 (LL5ZTO) as the anode. LL5ZTO doped with La is synthesized via a one-step solid-state route. The kinetics and structural stability of LZTO are enhanced by La-doping. Thus, LL5ZTO exhibits good Li-storage performance. The discharge specific capacity reaches 182.6 mAh g?1 at 3 A g?1 (120th cycle) for LL5ZTO. The LIC based on the LL5ZTO anode and the AC cathode delivers an energy density of 59.72 Wh kg?1 at 846.4 W kg?1, and a high power density of 8771 W kg?1 at 19.49 Wh kg?1. Furthermore, the capacity retention is over 90% after 3000 cycles for the LIC at 2 A g?1. The good electrochemical performance indicates that the constructed LIC is expected to use in advanced energy storage devices.  相似文献   

3.
《Ceramics International》2016,42(14):15464-15470
The TiN coated Li4Ti5O12 (LTO) submicrospheres with high electrochemical performance as anode materials for lithium-ion battery were synthesized successfully by solvothermal method and subsequent nitridation process in the presence of ammonia. The XRD results revealed that the crystal structure of LTO did not change after thermal nitridation process. The submicrospheres morphology of LTO and TiN film on the surface of LTO submicrospheres were characterized by FESEM and HRTEM, respectively. XPS result confirmed that a small amount of Ti changed from Ti4+ to Ti3+ after nitridation process, which will increase the electronic conductivity of LTO. Electrochemical results showed that electrochemical performance of TiN coated LTO anode materials compared favorably with that of pure LTO. Also its rate capability and cycling performance were apparently superior to those of pure LTO. The reversible capacity of TiN-LTO is 105.2 mA h g−1 at a current density of 10 C after 100 cycles and maintain 92.9% of its initial discharge capacity, while that of pure LTO is only 83.6 mA h g−1 with a capacity retention of 90.3%. Even at 20 C, the discharge capacity of TiN coated LTO sample is 101.3 mA h g−1, compared with 77.3 mA h g−1 for pristine LTO in the potential range 1.0–2.5 V (vs. Li/Li+).  相似文献   

4.
In this paper, Li4Ti5O12 (LTO) hollow microspheres with the shell consisting of nanosheets have been synthesized via a hydrothermal route and following calcination. Because of the favorable transport properties of this hollow structure, it is the rate performance at high current densities which is exceptional. When the LTO hollow microspheres were used as the anode material in lithium ion battery, they exhibited superior rate performance and high capacity even at a very high rate (131 mAh g−1 at 50 C).  相似文献   

5.
《Ceramics International》2020,46(17):26923-26935
In this study, spinel lithium titanate (Li4Ti5O12, LTO) anode materials were synthesized from two titanium sources (P25 TiO2, 100% anatase TiO2) using a spray-drying method and subsequent calcination at various temperatures. The electrochemical performance of both a Li/LTO half cell and a LiNi0.5Mn1.5O4/LTO (LNMO/LTO) full cell were investigated. The electrochemical performance of the LTO material prepared from P25 TiO2 was superior to that of the LTO prepared from 100% anatase TiO2. After modification of LTO material with AlPO4, the LTO coated with 2 wt% of AlPO4 (denoted “2%AlPO4-LTO”) provided the best performances. The specific (delithiation) capacities of the 2%AlPO4-LTO anode material was 189.7 mA h g−1 at 0.1C/0.1C, 184.5 mA h g−1 at 1C/1C, 178.8 mA h g−1 at 5C/5C, and 173.1 mA h g−1 at 10C/10C. From long-term cycling stability tests, the specific capacity at the first cycle and the capacity retention after cycling were 185.5 mA h g−1 and 98.06%, respectively, after 200 cycles at 1C/1C and 182.1 mA h g−1 and 99.18%, respectively, after 100 cycles at 1C/10C. For the LNMO/2%AlPO4-LTO full cell, the average specific capacity (delithiation) and coulombic efficiency after the first five cycles were 164.8 mA h g−1 and 93.30%, respectively, at 0.1C/0.1C. The specific capacities at higher C-rates were 156.1 mA h g−1 at 0.2C/0.2C, 135.7 mA h g−1 at 1C/1C, 97.5 mA h g−1 at 3C/3C, and 46.5 mA h g−1 at 5C/5C. After twenty-five cycles, the C-rate returned to 1C/1C and the specific capacity, coulombic efficiency, and capacity retention were maintained at 134.1 mA h g−1, 99.17%, and 98.82%, respectively.  相似文献   

6.
Carbon nanotube-encapsulated SnO2 (SnO2@CNT) core–shell composite anode materials are prepared by chemical activation of carbon nanotubes (CNTs) and wet chemical filling. The results of X-ray diffraction and transmission electron microscopy measurements indicate that SnO2 is filled into the interior hollow core of CNTs and exists as small nanoparticles with diameter of about 6 nm. The SnO2@CNT composites exhibit enhanced electrochemical performance at various current densities when used as the anode material for lithium-ion batteries. At 0.2 mA cm?2 (0.1C), the sample containing wt. 65% of SnO2 displays a reversible specific capacity of 829.5 mAh g?1 and maintains 627.8 mAh g?1 after 50 cycles. When the current density is 1.0, 2.0, and 4.0 mA cm?2 (about 0.5, 1.0, and 2.0C), the composite electrode still exhibits capacity retention of 563, 507 and 380 mAh g?1, respectively. The capacity retention of our SnO2@CNT composites is much higher than previously reported values for a SnO2/CNT composite with the same filling yield. The excellent lithium storage and rate capacity performance of SnO2@CNT core–shell composites make it a promising anode material for lithium-ion batteries.  相似文献   

7.
A flexible, free-standing composite anode with Li4Ti5O12 nanosheet arrays anchoring on plain-weaved carbon fiber cloth (LTO@CC) is prepared by a hydrothermal and post-annealing process assisted by a TiO2 seed layer. The LTO@CC anode free from polymeric binder and conducting agent exhibited much higher lithium storage capacity and cycling stability than the conventional slurry-processed electrode using the dandelion-like Li4Ti5O12 microspheres prepared by the same hydrothermal process. A high specific capacity of 128.8 mA h g?1 was obtained at a current rate of 30 C (1 C = 175 mA g?1), and almost negligible capacity loses was observed when the cell was cycled at 10, 20 and 30 C each for 100 cycles. The carbon fiber matrix contributed to Li storage at low current rate, but the LTO nanosheet arrays have played the dominant role on the excellent rate capability. The improved electrochemical performance can be attributed to the synergetic effect between the hierarchical Li4Ti5O12 nanosheet arrays and the carbon fiber matrix, which integrated short Li+ diffusion length, three-dimensional conductive architecture and well preserved structural integrity during the high rate and repeated charge-discharge measurements.  相似文献   

8.
《Ceramics International》2017,43(2):1650-1656
To improve the electrochemical and anti flatulence performance of Li4Ti5O12, Ag modified Li4Ti5O12 (LTO) with high electrochemical performance as anode materials for lithium-ion battery was synthesized successfully by two-step solid phase sintering and subsequent electroless plating process in the presence of silver. The effect of Ag modification on the physical and electrochemical properties were investigated by the extensive material characterization of X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM). The results showed that the samples possessed single spinel structure, it could be observed that the LTO/Ag composite and the pure LTO shared the same vibration frequencies, which indicated that the crystal structure of LTO didn’t change after electroless plating process, and the particles were uniformly and regularly shaped within 0.5–1.0 µm. Electrochemical performance of the samples were evaluated by the charging and discharging, cyclic voltammetry, electrochemical impedance spectroscopy, cycling and rate tests. It's obvious that the LTO/Ag composite prepared at the 10 min of electroless plating showed the highest performance with capacitance of 182.3 mA h/g at 0.2 C current rates. What's more, the LTO/Ag composites still maintained 92% of its initial capacity even after 50 charge/discharge cycles. Modification of appropriate Ag not only benefits the reversible intercalation and deintercalation of Li+, but also improves the diffusion coefficient of lithium ion. Besides, modification of appropriate Ag lower electrochemical polarization leads to higher conductivity and cycle performance of LTO, which is consistent with the results of the best reversible capacities.  相似文献   

9.
《Ceramics International》2022,48(10):14098-14106
Transitional metal selenides are considered as potential anode candidates for sodium-ion batteries (SIBs) because of their relatively high theoretical capacity and environmental benign. However, the large volume change derived from the conversion reaction and the sluggish kinetics due to the inherent low electrochemical conductivity hinder their practical application. Herein, composite materials of NiSe2 encapsulated in nitrogen-doped TiN/carbon nanoparticles with carbon nanotubes (CNTs) on the surface (NiSe2@N-TCP/CNTs) are fabricated via pyrolysis and selenization processes. In this composite, TiN inside the carbon matrix can enhance the conductivity and structural stability. CNTs that are in-situ grown on the surface not only further enhance the conductivity of the composites, but also offer sufficient space to buffer the volume expansion and alleviate serious aggregation of NiSe2 nanoparticles. Benefit from these merits, the NiSe2@N-TCP/CNTs showed a lower charge transfer resistance and a faster Na+ diffusion rate than materials without growing CNTs. When used as the anode of SIBs, the NiSe2@N-TCP/CNTs electrode delivered a reversible capacity of 344.0 mAh g?1 after 1000 cycles at 0.2 A g?1, and still maintained at 272.7 mAh g?1 even at a high current density of 2 A g?1. The remarkable electrochemical performance is mainly attributed to the special designed hierarchical structures and pseudocapacitance sodium storage behavior.  相似文献   

10.
Surface doping of Li4Ti5O12 (LTO) with Ti3+ ions is an effective way to enhance its electrochemical properties for lithium ion batteries (LIBs). Herein, a molten salt approach was reported to synthesize Ti3+ self-doped LTO powder. The reaction mechanism and the role of molten salt for the synthesis have been systemically discussed. Finally, electrochemical performance of the LTO powder was preliminarily evaluated as anode material of LIBs. The molten salt accelerated the mass transportation for the formation of LTO by transferring a solid diffusion to the diffusion of ions in a liquid media. Self-doping of Ti3+ ions on the surface of LTO particles was achieved by controlling equilibriums of chemical reactions in the reactor. Electrochemical performance of the LTO powders was effectively promoted by doping Ti3+ ions on the surface. The discharge capacity of the Ti3+ self-doped LTO powder prepared at 850°C was 171 mAhg−1, and the capacity dacayed 9.9% after 200 cycles at a rate of 0.5 C.  相似文献   

11.
Spinel structured LTO (lithium titanium oxide), Li4Ti5O12, materials have gained renewed interest in electrodes for lithium-ion batteries. Powder precursors were mixed by HEBM (high energy-ball mill) and Li4Ti5O12 was formed by calcinations at high temperature. The influence of excess Li on the structural characteristics of lithium titanium oxide was investigated. According to the XRD and SEM analysis, uniformly distributed Li4Ti5O12 particles were synthesized. Li4Ti5O12 had different characteristics due to the precursor sizes and the heat treatment temperatures. LTO from micro TiO2 showed the highest discharge capacity at 750 °C for 12 h. LTO from nano TiO2 showed the highest discharge capacity at 700 °C for 12 h. Lithium-ion battery with Li4Ti5O12 anode and lithium metal cathode showed the capacity of 170 mAh/g at 1.0–3.0 V.  相似文献   

12.
Binary transition-metal oxides with spinel structure have great potential as advanced anode materials for lithium-ion batteries (LIBs). Herein, NiFe-NiFe2O4/ reduced graphene oxide (rGO) composites are obtained via a facile cyanometallic framework precursor strategy to improve the lithium storage performance of NiFe2O4. In the composites, NiFe-NiFe2O4 nanoparticles with adjustable mass ratios of NiFe2O4 to NiFe alloy are homogeneously deposited on rGO sheets. As anode material for LIBs, the optimized NiFe-NiFe2O4/rGO composite displays remarkably enhanced lithium storage performance with an initial specific capacity as high as 1362 mAh g−1 at 0.1 A g−1 and a decent capacity retention of ca. 80% after 130 cycles. Besides, the composite delivers a reversible capacity of 550 mAh g−1 at 1 A g−1 after 300 cycles. During the charge–discharge cycles, the aggregation of the NiFe-NiFe2O4 nanoparticles and the structural collapse of the electrode can be well alleviated by rGO sheets. Moreover, the conductivity of the electrode can be significantly improved by the well-conductive NiFe alloy and rGO sheets. All these contribute to the improved lithium storage performance of NiFe-NiFe2O4/rGO composites.  相似文献   

13.
The composite of silicon carbonitride (SiCN) and carbon nanotubes (CNTs) was synthesized by sintering the mixture of polysilylethylenediamine-derived amorphous SiCN and multi-walled CNTs at a temperature of 1,000 °C for 1 h in argon. The as-prepared SiCN–CNTs material, which was used as anode active substance in a lithium ion battery, showed excellent electrochemical performance. Charge–discharge tests showed the SiCN–CNTs anode provided a high initial specific discharge capacity of 1176.6 mA h g−1 and a steady specific discharge capacity of 450–400 mA h g−1 after 30 charge–discharge cycles at 0.2 mA cm−2. Both of the abovementioned values are higher than that of pure polymer-derived SiCN, CNTs, and commercial graphite at the same charge–discharge condition. It was deduced that the CNTs in the composite not only improved the electronic conductivity and offered channels and sites for the immigrating and intercalating of Li+ but also stabilized the structure of the composite.  相似文献   

14.
Insertion type material has been attracted plenty of attentions as the anode of sodium ion batteries (SIBs) due to the low volume change induced long cycle stability. H1.07Ti1.73O4 (HTO), a two-dimensional layered material, is a new insertion type anode material for SIBs reported in this study. Layered HTO composites were decorated with rGO nanosheets via an electrostatic assembly method followed by hydrothermal treatment. When adapted as the anode material of SIBs, HTO@rGO composite exhibits an enhanced sodium ion storage behavior, including high rate capability and long cycle stability. It can deliver high capacities of 142.8 and 66.7 mA h g−1 at 100 and 10 000 mA g−1, respectively. Moreover, it can keep a capacity of 75.1 mA h g−1 at 5 A g−1 after even 5000 cycles, corresponding to a high capacity retention of 70.8% (0.0058% capacity decay per cycle). HTO exhibits a small volume expansion of 19.6% by in-situ transmission electron microscopy (in-situ TEM). The diffusion coefficient of sodium ions is increased from 1.77 × 10−14 cm2 s−1 in HTO composites to 4.80 × 10−14 cm2 s−1 in HTO@rGO composites. Our designed and synthesized HTO@rGO provides a new route for high rate and long cycle stable SIBs anode materials.  相似文献   

15.
As a promising anode material, PbLi2Ti6O14 has attracted the attention of many researchers. In this work, a series of PbLi2Ti6O14 are prepared by solid state method at five different calcination temperatures and used as anode materials in lithium ion batteries. Through a series of tests, the results show that the phase purity, morphology and electrochemical performance of PbLi2Ti6O14 can be seriously influenced by calcination temperature. When the calcination temperature is 900?°C, the phase-pure PbLi2Ti6O14 can be obtained with relatively small particle size, excellent cycle performance and outstanding lithium ion diffusion behavior. It provides an initial charge capacity of 151.3?mA?h?g?1 at 100?mA?g?1. After 100 cycles, it shows a reversible capacity of 142.0?mA?h?g?1 with superior capacity retention of 93.85%. In contrast, PbLi2Ti6O14 formed at 800?°C displays an unsatisfactory performance due to the presence of impurity, even though it has the smallest particle size and the largest lithium ion diffusion coefficient among the five samples. The reversible capacity is only 82.6?mA?h?g?1 after 100 cycles with capacity retention of 53.9%. In order to further study the lithium ion diffusion behavior of PbLi2Ti6O14, the in-situ X-ray diffraction technique is also implemented. It is found that during the lithiation/delithiation process, the stable framework can effectively inhibit the volume change and ensures the excellent electrochemical performance of PbLi2Ti6O14.  相似文献   

16.
《Ceramics International》2022,48(16):23334-23340
Titanium niobate prepared by traditional techniques has the shortcomings of low ion diffusion coefficient as well as poor electrical conductivity, which drastically reduce its applicability. In this work, we prepare carbon coated Ti2Nb10O29 hollow submicron ribbons (Ti2Nb10O29@C HSR) using a simple electrospinning procedure. As anode material for lithium-ion batteries (LIBs), it delivers a high charge capacity of 259.7 mAh g?1 at 1 C with low capacity loss of 0.013% in long-term cycles. Increased the current density to 5 C, Ti2Nb10O29@C HSR can maintain a reversible capacity of 189.9 mAh g?1, indicating its good rate performance. Additionally, this work uses in-situ X-ray diffraction (XRD) to provide an explanation for the lithium storage process in Ti2Nb10O29@C HSR, demonstrating the high reversibility during charge/discharge cycles. Therefore, Ti2Nb10O29@C HSR has outstanding cycle adaptability and structural reversibility to be a promising anode for LIBs.  相似文献   

17.
《Ceramics International》2022,48(6):7687-7694
A novel negative material consisting of graphene nanotubes and ultrathin MoS2 is synthesized by a simple one-step hydrothermal method assisted with Sodium chloride. The MoS2/Graphene electrodes deliver a specific capacity of 1350 mAh g?1 under 0.1 A g?1 and high rate capability (retaining 85.5% capacity from 0.1 A g?1 to 0.8 A g?1). A high remarkable capacity of 820 mAh g?1 can still be recovered at 0.5 A g?1 after 500 cycles, and the average coulombic efficiency was as high as 99.98% during the additional 500 cycles. The excellent Li-ion storage performance of MoS2/Graphene nanotubes may be attributed to the ultra-thin MoS2 flakes and curled graphene nanotubes. This structural feature has a strong adsorption capacity for lithium ions, which can provide a broad space for ion storage. A large number of active sites dispersed in the layered molybdenum disulfide promote the kinetics of the electrochemical reaction, empowering the ultra-thin layered molybdenum disulfide to get a higher theoretical capacity. In addition, the existence of the tubular structure alleviates volume expansion and provides a way for the rapid movement of electrons and diffusion of Li+ during repeated cycles.  相似文献   

18.
As the most widely used energy storage device today, lithium-ion batteries (LIBs) will determine the convenience and durability of people's future energy life to a certain extent. At present, there are many and mature researches on cathode materials for LIBs, so it is crucial to seek a high-performance anode material. In recent years, due to considerable theoretical capacity, abundant raw material reserves and unique physicochemical properties, Zn and Mn selenium compounds have become research hotspots for LIBs anode materials. In this work, a new MOF material Zn–Mn-ptcda was synthesized by a simple hydrothermal reaction. Using Zn–Mn-ptcda as the precursor, two-dimensional (2D) elliptical leaf-shaped Zn0·697Mn0·303Se/C composites were synthesized by direct selenization. Zn0.697Mn0.303Se/C has a large specific surface area of 213.9 m2 g?1, belongs to the mesoporous structure, and possesses excellent lithium storage performance, especially the rate performance. It has a reversible capacity of 1005.14 mAh g?1 after 110 cycles at a current density of 100 mA g?1. After 1000 cycles at a high current density of 1 A g?1, it still maintains a good capacity of 653.79 mAh g?1.  相似文献   

19.
《Ceramics International》2017,43(10):7908-7915
In this work, Li5Cr7Ti6O25 as a new anode material for rechargeable batteries is fabricated through a simple sol-gel method at different calcination temperatures. The X-ray diffraction, scanning electron microscopy, high resolution transmission electron microscopy, charge/discharge curve and cyclic voltammograms are utilized to study the crystal structures, morphologies and electrochemical properties of as-obtained Li5Cr7Ti6O25 samples. The impact of calcination temperatures on morphologies and electrochemical properties of Li5Cr7Ti6O25 is discussed in detail. The test result shows that the 800 °C is a proper calcination temperature for Li5Cr7Ti6O25 with excellent electrochemical properties. Cycled at 200 mA g−1, it displays a high initial reversible capacity of 146.6 mA h g−1 and retains a considerable capacity of 130.8 mA h g−1 after 300 cycles. Even cycled at large current density of 500 mA g−1, the initial reversible capacity of 129.6 mA h g−1 with the capacity retention of 88% after 300 cycles is achieved, which is obviously higher than that of Li5Cr7Ti6O25 prepared at 700 °C (80.5 mA h g−1 and 68%) and 900 °C (98.4 mA h g−1 and 80%). In addition, in-situ XRD analysis reveals that Li5Cr7Ti6O25 exhibits a reversible structural change during lithiation and delithiation processes. The above prominent electrochemical performance indicates the great potential of the Li5Cr7Ti6O25 obtained at 800 °C as anode material for rechargeable batteries.  相似文献   

20.
Lithium-sulfur (Li–S) batteries are attractive due to their high theoretical energy density. However, conventional Li–S batteries with liquid electrolytes undergo polysulfide shuttle-effect and lithium dendrite formation during charge/discharge process, leading to poor electrochemical performance and safety issues. Garnet type Li7La3Zr2O12 (LLZO) solid-state electrolyte (SSE) restricts the penetration of polysulfides and exhibits high ionic conductivity at room temperature (RT). Herein, Li6.5La3Zr1.5Nb0.5O12 (LLZNO) ceramic electrolyte using Li3PO4 (LPO) as sintering aids (LLZNO-LPO) is prepared by the rapid sintering method and is applied to construct a shuttle-effect free solid-state Li–S battery. The SSE displays high conductive pure cubic-LLZO phase; during the rapid sintering, LPO melts and junctions the voids between the grains, thus improves Li+ conductivity. As a result, the LLZNO-LPO ceramic electrolyte with Li+ conductivity of 4.3 × 10?4 S cm?1 and high critical current density (CCD) of 1.2 mA cm?2 is obtained at RT. The Li–S solid-state battery which utilizes LLZNO-LPO ceramic electrolyte can deliver an initial discharge capacity of 943 mA h·g?1 and 602 mA h·g?1 retention after 60 cycles. In the same time, the initial coulombic efficiency is as high as 99.5%, indicating that the SSE can effectively block the polysulfide shuttle towards the Li anode and fulfill a shuttle-free Li–S battery.  相似文献   

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