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1.
Three kinds of novel carboxyl modification tubular carbon nanofibers (CMTCFs) and MnO2 composites materials (CMTCFs/MnO2) are prepared by combining hyper-crosslinking, liquid phase oxidation and hydrothermal technology. The complex morphology and crystal phase of MnO2 in CMTCFs/MnO2 are effectively regulated by adjusting the hydrothermal reaction time. The δ-MnO2 nanosheet-wrapped CMTCFs (CMTCFs@MNS) are used as anode and compared with the other two CMTCFs/MnO2. Electrochemical analysis shows that CMTCFs@MNS electrode exhibits a large reversible capacity of 1497.1 mAh g−1 after 300 cycles at 1000 mA g−1 and a long cycling reversible capacity of 400.8 mAh g−1 can be maintained after 1000 cycles at 10 000 mA g−1. CMTCFs@MNS manifests an average reversible capacity of 256.32 mAh g−1 at 10 000 mA g−1 after twelve changes in current density. In addition, the structural superiority of CMTCFs@MNS electrode is clarified by characterizing the microscopic morphology and crystal phase of the electrode after electrochemical performance test.  相似文献   

2.
《Ceramics International》2023,49(10):15793-15801
The degradation of the cobalt-zinc oxide structure and its poor conductivity during the charge and discharge limit their further applications for lithium ion storage. Herein, ZnCo2O4@carbon nanofiber composite with nano-fibrous structure is obtained by electrospinning, annealing in argon and low-temperature oxidation to effectively overcome the above issue. The active sites of ZnCo2O4 are evenly dispersed inside the carbon nanofibers, which can effectively avoid its aggregation and improve electrical conductivity. Additionally, the stable nanofibrous structure can maintain structural stability. The composite exhibits superior lithium ion storage capacity when being served as anode electrode. The ZnCo2O4@carbon nanofiber electrode possesses a high capacity of 1071 mA h g−1 at 0.1 A g−1. Besides, the electrode shows an outstanding rate capability of 505 mA h g−1 at 3 A g−1 and maintain 714 mA h g−1 after 250 cycles when current density is adjusted to 0.2 A g−1 again. Additionally, the electrode has an outstanding long-cycle performance, which remains a capacity of 447.165 mA h g−1 at 0.5 A g−1 after 500 cycles and 421.477 mA h g−1 at 1 A g−1 after 518 cycles. This result demonstrates that ZnCo2O4@carbon nanofiber composite has potential application prospects in the fields of advanced energy storage.  相似文献   

3.
《Ceramics International》2016,42(11):12644-12650
Hierarchical nickel oxide/graphene oxide (NiO/GO) and nickel oxide/graphene oxide/silver (NiO/GO/Ag) heterostructures were sucessfully fabricated as high-performance supercapacitors electrode materials by using a hydrothermal process and a photoreduction process. The experimental results showed that the NiO/GO/Ag heterostructure electrodes showed better electrochemical performance than those of NiO/GO and bare NiO nanosheets. The NiO/GO/Ag electrode exhibited a higher specific capacitance of 229 F g−1 at a current density of 1 A g−1, higher than that of 161 F g−1 for NiO/GO composites. Furthermore, NiO/GO/Ag electrode also showed good rate capability (still 200 F g−1 at 6 A g−1) and cycling stability (24% loss after 2000 repetitive cycles at a scan rate of 20 mV s−1). The enhanced capacitive performance of the NiO/GO/Ag composites was mainly attributed to the introduction of Ag nanoparticles, which increased the electrical conductivities of the composites, and promoted the electron transfer between the active components. This study suggested that NiO/GO/Ag composites were a promising class of electrode materials for high performance energy storage applications.  相似文献   

4.
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   

5.
《Ceramics International》2023,49(13):21355-21362
Attributed to its environmental friendliness, high theoretical energy density, and abundant sodium resource, rechargeable hybrid sodium-air batteries (HSABs) are expected to become a promising pioneer of the new-generation green energy storage device. However, HSABs suffer from the high voltage gap, low energy conversion efficiency, and poor cycle stability due to the low catalytic activity of catalysts caused by the degradation of polymer binders. Herein, hierarchical mesoporous NiO nanosheet arrays grown on carbon papers (CP) (NiO NA@CP) were synthesized by a facile and efficient hydrothermal route and calcination process, which acts as an integrated electrode for HSABs. Compared with traditional air electrodes that contain a polymer binder and conductive carbon, the integrated NiO NA@CP electrode prevents the aggregation of catalysts, improves the electronic conductivity by good electric contact and ensures its robust mechanical stability. In addition, NiO NA@CP electrode with the abundant porosity and large specific area offers plenty of active sites and shortens ion transfer length and rapid mass transport in ORR/OER process, leading to excellent oxygen catalytic activities. HSABs with NiO NA@CP electrode show a low overpotential of 0.65 V, a state-of-the-art power density (7.53 mW cm−2), as well as an excellent cyclability of 170 cycles (over 170 h) at a current density of 0.1 mA cm−2.  相似文献   

6.
Hollow spherical NiO particles were prepared using the spray pyrolysis method with different concentrations of precursor. The electrochemical properties of the NiO electrodes, which contained a new type of binder, carboxymethyl cellulose (CMC), were examined for comparison with NiO electrodes with polyvinylidene fluoride (PVDF) binder. The electrochemical performance of NiO electrodes using CMC binder was significantly improved. For the cell made from 0.3 mol L−1 precursor, the irreversible capacity loss between the first discharge and charge is about 43 and 24% for the electrode with PVDF and CMC binder, respectively. The cell with NiO–CMC electrode has a much higher discharge capacity of 547 mAh g−1 compared to that of the cell with NiO–PVDF electrode, which is 157 mAh g−1 beyond 40 cycles.  相似文献   

7.
The large-scale application of Si-based anodes is impeded by their fast capacity decay, which is mainly attributed to the huge volume expansion upon cycling. The employment of functional binders is one efficient method to mitigate this issue. In this work, a four-armed polyacrylic acid (4A-PAA) homopolymer is explored as a remarkably effective binder for Si-based anodes. The 4A-PAA binder is prepared via an atom transfer radical polymerization, followed by ester hydrolysis. Compared to the conventional linear polyacrylic acid (PAA) binder, the 4A-PAA not only shows enhanced toughness due to its decreased molecular regularity and intramolecular hydrogen bond but also exhibits increased binding strength because of its multidimensional binding structure. As a result, the SiOx/graphite electrode using the 4A-PAA retains a capacity retention of 89.1% and a capacity of 558.1 mAh g−1 after 200 cycles at 0.16 A g−1, which are superior to the PAA electrode, corresponding to 80.4% and 469.3 mAh g−1, respectively. The improved performance is attributed to the employment of the 4A-PAA, which mitigates the volume change of the SiOx/graphite anode. This work not only offers a promising binder for Si-based anodes but also presents a universal solution for other anodes with high volume expansion during cycling.  相似文献   

8.
《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   

9.
《Ceramics International》2023,49(15):24802-24811
Na3V2(PO4)3 (NVP) has been deemed as a promising cathode because of high capacity and good stability. Nevertheless, poor intrinsic conductivity seriously limits its further application. Herein, partial Ba2+ substitution on V3+ site is introduced to modify NVP in terms of increasing cell volume due to larger ionic radius of Ba2+ and generating beneficial hole carriers derived from p-type doping. The expanded crystal channels efficiently facilitate the Na + migration and the hole carriers are beneficial for transfer charge to improve electronic conductivity. Ba2+ doping further enhances the structural stability due to the pillar effect, which has been proved by DSC measurement. The increase of exothermic peak temperature and decrease of heat release rate demonstrates the excellent thermal stability of NVBa0.07P@CNTs. Moreover, disordered carbon layer and enwrapped CNTs construct an effective network to provide abundant routes for electronic transportation. Notably, the optimized NVBa0.07P@CNTs delivers superior electrochemical performance in both half and full cells. It releases a capacity of 117.23 mA h g−1 at 0.1C and submits a capacity of 101.99 mA h g−1 with retention of 80% at 15 C over 2000 cycles. Even at 50 C, it still delivers a high value of 78.33 mA h g−1.  相似文献   

10.
《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   

11.
Designing defect-rich MoS2/C architectures with three-dimensional (3D) porous frame effectively improve the electrochemical performance of lithium-ion batteries (LIBs) owing to the improved conductivity and decreased diffusion distance of Li+ ions for lithium storage. Herein, we report a reliable morphology engineering method combining with tunable defects to synthesize defect-rich MoS2 nanosheets with a few layers entrapped carbon sheath, forming a 3D porous conductive network architecture. The defect-rich MoS2 nanosheets with expanded interlayers can provide a shortened ion diffusion path, and realize the 3D Li+ diffusion with faster kinetics. A 3D conductive interconnected carbon network is able to improve interparticle conductivity, concurrently maintaining the structural integrity. Benefiting from these intriguing features, the as-prepared MoS2/C architectures exhibit excellent electrochemical performance: a high reversible capacity of 1163 mAh g−1 at a current density of 0.1 A g−1 after 100 cycles and a high rate capability of 800 mAh g−1 at 5 A g−1. Defect content in MoS2/C architectures can be obtained by changing H2 concentration. Compared with the counterparts with few defects, the defect-rich MoS2/C architectures show improved electrochemical stability with a superior cycle life, illustrating a highly reversible capacity of 751 mAh g−1 at 0.5 A g−1 after 500 cycles.  相似文献   

12.
《Ceramics International》2020,46(15):24155-24161
To solve the problem of the rapid decrease in capacity caused by poor conductivity, polysulfide shuttling, and the volume expansion associated with the reaction process, we attempt to use metal-organic framework (MOF) Fe-soc coated with reduced graphene oxide through electrostatic adsorption as a sulfur carrier material for lithium sulfur batteries. The research results show that S/Fe-soc@rGO has a high initial discharge specific capacity of 1634.3 mA h g−1 with a stable specific capacity retention rate of 865.3 mA h g−1 after 80 cycles and displays enhanced rate performance with high discharge specific capacities of 638.8 and 334.3 mA h g−1 after 200 cycles at 0.5 and 1 C, respectively. Fe-soc has unsaturated metal sites can adsorb sulfur and polysulfide, effectively bind polysulfide, symmetrical stable structure is conducive to speed up the electron and ion transmission efficiency while buffering the volume expansion during charge and discharge. In addition, reduced graphene oxide as a coating layer can better assist Fe-soc to increase the utilization rate of sulfur, and improve the conductivity of the cathode material, thereby improving the cycle performance and rate performance of lithium-sulfur batteries. This article is also expected to stimulate the application of MOF derivatives in energy storage materials.  相似文献   

13.
《Ceramics International》2023,49(13):21729-21736
MoO3 is a kind of promising cathode material for lithium-ion batteries (LIBs), owing to its high specific capacity (279 mA h g−1) and layered structure. However, low electrical conductivity and sluggish reaction kinetics results in poor rate and Li-ions storage capability. The introduction of oxygen vacancies (OVs) can promote Li+ diffusion, and produce great electrical conductivity. Here, we report a strategy to synergize the merits of OVs by pulsed laser deposition (PLD) by adjusting oxygen partial pressures (2~20 Pa). The appropriate OVs concentration not only significantly approves electrochemical performance but also increases pseudocapacitance contribution. The Li-ion diffusion coefficient of MoO3−x is remarkably improved by one or two orders of magnitude compared with that of MoO3. Therefore, this facile and efficient strategy on OVs could afford a reference for other metal oxides for high-performance electrode materials.  相似文献   

14.
《Ceramics International》2022,48(14):20020-20032
Vanadium disulfide (VS2) is deemed to be a competitive active material in electrochemical energy storage field in both lithium-ion battery and supercapacitor owing to its unique chemical and physical property. Nevertheless, serious aggregation and structure damage in continuous charge-discharges would result in a decreased capacity, an inferior cycling stability and a poor rate capability, which severly limits the practical application of VS2. In this current work, a hierarchical porous nanostructured composite composed of VS2 nanoparticles confined in gelatin-derived nitrogen-doped carbon network (VS2-NC) was successfully designed and synthesized via a simple freeze drying plus an annealing method. In this VS2-NC composite, porous architecture is conductive to providing high active surface areas, facilitating the access of electrolyte into active materials and ion diffusion. The confinement of carbon matrix on VS2 nanoparticles is beneficial to inhibition of the volume change, reinforcement of the structural stability and improvement of the overall electrical conductivity of composite. Benefitting from the advantages mentioned above, the as-prepared VS2-NC electrode demonstrates outstanding electrochemical performances. Employed as an anode for lithium ion battery, VS2-NC delivers a relatively high reversible capacity about ~1061 mA h g?1 in 200-cycle test at 100 mA g?1. When applied in supercapacitor, VS2-NC electrode manifests a large pseudocapacitance of 407.3 F g?1 at a current density of 10 A g?1 and superior cycling stability.  相似文献   

15.
《Ceramics International》2020,46(12):19966-19972
Well-designed nanostructures are very critical to the lithium-storage performance of electrode materials. To enhance the electrochemical performance of zinc oxide anode materials, a capsule structure, composed of carbon shell and its encapsulating ZnO microsphere, is designed. This capsule structured ZnO/C nanocomposite microspheres are prepared by a sol-gel method combined with two calcination processes. The carbon capsule shows great advantages of enhancing the structural stability of active material, reducing the formation of solid electrolyte interface (SEI) layer, and improving the conductivity of electrode. These factors are quite beneficial to the improvement of cycling stability, initial coulombic efficiency and rate capability. Consequently, capsule structured ZnO/C nanocomposite microspheres deliver an initial charge capacity of 790 mA h g−1, an initial coulombic efficiency of 71%, and a reversible capacity retention of 63% after 100 cycles, all of which are higher than those of pure ZnO microspheres. These results suggest that the design of carbon encapsulated ZnO microsphere is quite effective for enhancing the lithium-storage properties and can also show general significance for developing high-performance electrode materials.  相似文献   

16.
Micro-scaled spherical CoSn2/Sn alloy powders synthesized from oxides of Sn and Co via carbothermal reduction at 800 °C were examined for use as anode materials in Li-ion battery. The phase composition and particle morphology of the CoSn2/Sn alloy composite powders were investigated by XRD, SEM and TEM. The prepared CoSn2/Sn alloy composite electrode exhibits a low initial irreversible capacity of ca. 140 mAh g−1, a high specific capacity of ca. 600 mAh g−1 at constant current density of 50 mA g−1, and a good rate capability. The stable discharge capacities of 500-515 mAh g−1 and the columbic efficiencies of 95.8-98.1% were obtained at current density of 500 mA g−1. The relatively large particle size of CoSn2/Sn alloy composite powder is apparently favorable for the lowering of initial capacity loss of electrode, while the loose particle structural characteristic and the Co addition in Sn matrix should be responsible for the improvement of cycling stability of CoSn2/Sn electrode.  相似文献   

17.
The etching strategy of metal-organic frameworks is an effective process to prepare hollow electrode materials for enhanced electrochemical performance. But the relatively low conductivity of these electrode materials limits their further application. In this work, a series of carbon quantum dots (CQDs) embedded ZIF-67 precursors (ZIF-67@CQDs-X, X = 1.25, 2.50, 5.00, 7.50) are synthesized firstly. Then, by a facile and controllable chemical etching process, the CQDs doped α-Co/Ni(OH)2 hollow nanocages (α-Co/Ni(OH)2@CQDs-X, X = 1.25, 2.50, 5.00, 7.50) are successfully constructed. The optimized α-Co/Ni(OH)2@CQDs-2.50 electrode delivers a high specific surface area (277.99 m2 g−1) and dramatically enhanced conductivity. Therefore, α-Co/Ni(OH)2@CQDs-2.50 electrode presents a high specific capacitance (700 C g−1, 1 A g−1), superior rate performance (550 C g−1, 10 A g−1) and excellent cycling lifespan (retaining 79.93% of initial capacitance after 10 000 cycles). Coupled with the high-performance PPD/rGO as a negative electrode, the fabricated Co/Ni(OH)2@CQDs-2.50//PPD/rGO device exhibits an outstanding energy density of 57.29 Wh kg−1 at the power density of 0.375 kW kg−1. It is proved that the CQDs embedding and chemical etching strategy are an effective way for constructing hollow materials with enhanced energy storage performance.  相似文献   

18.
Present investigation deals with the study of electrochemical properties of Bi2Te3/GO composite for its use as anode material in Li-ion batteries. The Bi2Te3/GO composite has been synthesized via polyol route. The surface morphology and structural properties of the as-prepared samples have been studied by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and Raman spectroscopy techniques. The phase of as-synthesized composite was found out to be rhombohedral as has been characterized by X-ray diffractometer. The presence of GO in the Bi2Te3 matrix has been confirmed by the presence of characteristic D and G bands in the Raman spectra. The as-synthesized composite showed the first cycle discharge/charge capacity of 752/514 mAh g−1 at the current density of 0.1 Ag−1, superior rate capability (~50 mAh g−1 at 2 Ag−1), and excellent cycling stability over 500 cycles at 0.1 Ag−1. The presence of GO in the matrix helps to enhance the electronic conductivity due to the rapid Li-ion diffusion and helps to shield the changes in volume during the cycling processes.  相似文献   

19.
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   

20.
In this paper, crystalline V2O3 and amorphous V2O3/C products are synthesized via one-pot solution combustion synthesis (SCS) method (completed within 2 minutes). The characteristics of combustion products could be tuned by changing the amounts of glucose. The as-synthesized crystalline V2O3 nanopowder consists of nanoparticles with average size of ~100 nm. Amorphous V2O3/C composite exhibits large porous microsheet structure in which oxygen vacancy-enabled amorphous V2O3 particles are embedded into N-doped carbon microsheets. The existence of oxygen vacancies can promote energetics for the transport of electrons and ions and maintain the integrity of sample surface morphology. Moreover, N-doping can enhance electrical conductivity and promote the diffusion of electrons and lithium ions. Amorphous V2O3/C composite possesses high reversible capacity and superior cycling stability (833 mAh g−1 at 1 A g−1 after 250 cycles, 867 mAh g−1 at 0.1 A g−1 after 100 cycles), indicating its potential as excellent anode material for lithium-ion battery. The proposed one-step, time- and energy-efficient SCS method has the potential to prepare other oxygen vacancy-enabled transition metal oxides for energy storage.  相似文献   

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