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1.
Nanoscale ; 2020 Apr 03.
Artigo em Inglês | MEDLINE | ID: mdl-32242584

RESUMO

Nickel sulfide (NiS2) is generally regarded as an appropriate anode for manufacturing new-type potassium-ion batteries (PIBs), while the development and application of NiS2 are hampered by poor intrinsic electrical conductivity and huge volumetric change during potassiation/de-potassiation. Herein, we construct self-adaptive NiS2 nanoparticles confined to a three-dimensional graphene oxide (NiS2/3DGO) electrode via in situ sulfurization and self-assembly processes. The as-obtained NiS2/3DGO exhibits high reversible capacity (391 mA h g-1) and outstanding rate behavior (stable cycling at 1000 mA g-1) for PIBs. Furthermore, in situ X-ray diffractometry and ex situ Raman test results elucidate partially reversible transformation from the cubic NiS2 phase to the KxNiS2 intermediate, followed by generating a Ni0 and K2S4 product. This phenomenon is caused by the conversion reaction mechanism of NiS2 nanocrystals along with an amorphous phase transition during the initial cycle. Such understandings may shed new light on the application of metal sulfides and give directions to design novel electrodes with desirable structural stability and lifespan.

2.
Carbohydr Polym ; 229: 115557, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31826433

RESUMO

Chitosan (CS) based self-assembled nanohydrogels are considered as promising platform for biomedicine, petrochemical, agricultural and food applications due to their unique biodegradability, nano-interface effect, and intelligent responsiveness. However, the most CS derivatives are prepared in heterogeneous system, which is unstable and environmentally unfriendly. In this work, a series of hydroxybutyl chitosan (HBC) was synthesized based on a green and homogeneous system (potassium hydroxide (KOH)/urea), which given this derivative interesting temperature responsive phase transformation behavior. HBC could change from dissolved state into nanohydrogel state in deionized water, when the temperature exceed its critical phase change temperature, and this process could be repeated more than 50 cycles (one cycle/day) without coagulation. The nanohydrogels solution exhibited concentration and temperature-dependent ultraviolet absorption and visible light regulation, which had great application potential in smart windows. This study provided a novel preparation method and extended the application of chitosan-based temperature responsive self-assembled nanohydrogels.

3.
Chem Commun (Camb) ; 55(58): 8486-8489, 2019 Jul 25.
Artigo em Inglês | MEDLINE | ID: mdl-31268100

RESUMO

Porous V2O5 microspheres are synthesized via spray-drying and employed as the cathode material for aqueous zinc-ion batteries (ZIBs). The obtained porous V2O5 microspheres exhibit an ultrahigh reversible capacity and superior rate and cycling performances. In particular, a discharge capacity of 401 mA h g-1 can be achieved at 100 mA g-1. The specific energy density reaches 286 W h kg-1, surpassing most reported V-based cathode materials. The super electrochemical performances demonstrate that the porous V2O5 microsphere is a promising cathode material for aqueous ZIBs.

4.
Nat Nanotechnol ; 14(6): 594-601, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-31036907

RESUMO

Despite considerable efforts to stabilize lithium metal anode structures and prevent dendrite formation, achieving long cycling life in high-energy batteries under realistic conditions remains extremely difficult due to a combination of complex failure modes that involve accelerated anode degradation and the depletion of electrolyte and lithium metal. Here we report a self-smoothing lithium-carbon anode structure based on mesoporous carbon nanofibres, which, coupled with a lithium nickel-manganese-cobalt oxide cathode with a high nickel content, can lead to a cell-level energy density of 350-380 Wh kg-1 (counting all the active and inactive components) and a stable cycling life up to 200 cycles. These performances are achieved under the realistic conditions required for practical high-energy rechargeable lithium metal batteries: cathode loading ≥4.0 mAh cm-2, negative to positive electrode capacity ratio ≤2 and electrolyte weight to cathode capacity ratio ≤3 g Ah-1. The high stability of our anode is due to the amine functionalization and the mesoporous carbon structures that favour smooth lithium deposition.

5.
Chem Commun (Camb) ; 54(78): 11029-11032, 2018 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-30215646

RESUMO

Unique graphene oxide-wrapped organic dipotassium terephthalate hollow microrods were synthesised using an abundant and renewable organic resource. They exhibit enhanced potassium storage compared to bulk K2TP, which can be ascribed to the fast K+ ion transfer kinetics, high electronic conductivity and short diffusion distance.

6.
Nanoscale ; 10(27): 12963-12969, 2018 Jul 13.
Artigo em Inglês | MEDLINE | ID: mdl-29971285

RESUMO

Metal oxides are considered as attractive candidates as anode materials for lithium ion batteries (LIBs) due to their high capacities compared to commercialized graphite. However, fast capacity fading, which is caused by inherent large volume expansions and agglomeration of active particles upon cycling, is a great challenge. Herein, we propose the design of porous CaFe2O4 electrode material to address the above issue. Compared to pristine iron oxides, CaFe2O4 exhibits a distinct trade-off in terms of high capacity and long-term stability, which is beneficial to the potential practical applications. Such a trade-off effect is attributed to the synergistic effect between the porous structure and the in situ formed CaO nanograins during charging/discharging processes. This work provides an effective strategy in achieving anode materials with high capacity and long-term stability for next-generation LIBs.

7.
Small ; 14(26): e1800659, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29806173

RESUMO

High capacity transition-metal oxides play significant roles as battery anodes benefiting from their tunable redox chemistry, low cost, and environmental friendliness. However, the application of these conversion-type electrodes is hampered by inherent large volume variation and poor kinetics. Here, a binary metal oxide prototype, denoted as nonhierarchical heterostructured Fe2 O3 /Mn2 O3 porous hollow spheres, is proposed through a one-pot self-assembly method. Beyond conventional heteromaterial, Fe2 O3 /Mn2 O3 based on the interface of (104)Fe2O3 and (222)Mn2O3 exhibits the nonhierarchical configuration, where nanosized building blocks are integrated into microsized spheres, leading to the enhanced structural stability and boosted reaction kinetics. With this design, the Fe2 O3 /Mn2 O3 anode shows a high reversible capacity of 1075 mA h g-1 at 0.5 A g-1 , an outstanding rate capability of 638 mA h g-1 at 8 A g-1 , and an excellent cyclability with a capacity retention of 89.3% after 600 cycles.

8.
Nanoscale ; 10(15): 6820-6826, 2018 Apr 19.
Artigo em Inglês | MEDLINE | ID: mdl-29595204

RESUMO

Antimony (Sb) represents a promising anode for K-ion batteries (KIBs) due to its high theoretical capacity and suitable working voltage. However, the large volume change that occurs in the potassiation/depotassiation process can lead to severe capacity fading. Herein, we report a high-capacity anode material by in situ confining Sb nanoparticles in a three-dimensional carbon framework (3D SbNPs@C) via a template-assisted freeze-drying treatment and subsequent carbothermic reduction. The as-prepared 3D SbNPs@C hybrid material delivers high reversible capacity and good cycling stability when used as the anode for KIBs. Furthermore, cyclic voltammetry and in situ X-ray diffraction analysis were performed to reveal the intrinsic mechanism of a K-Sb alloying reaction. Therefore, this work is of great importance to understand the electrochemical process of the Sb-based alloying reaction and will pave the way for the exploration of high performance KIB anode materials.

9.
ACS Appl Mater Interfaces ; 10(12): 10022-10028, 2018 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-29493210

RESUMO

Symmetric sodium-ion batteries (SIBs) are considered as promising candidates for large-scale energy storage owing to the simplified manufacture and wide abundance of sodium resources. However, most symmetric SIBs suffer from suppressed energy density. Here, a superior congeneric Na4V2(PO4)3 anode is synthesized via electrochemical preintercalation, and a high energy density symmetric SIB (Na3V2(PO4)3 as a cathode and Na4V2(PO4)3 as an anode) based on the deepened redox couple of V4+/V2+ is built for the first time. When measured in half cell, both electrodes show stabilized electrochemical performance (over 3000 cycles). The symmetric SIBs exhibit an output voltage of 3.0 V and a cell-level energy density of 138 W h kg-1. Furthermore, the sodium storage mechanism under the expanded measurement range of 0.01-3.9 V is disclosed through an in situ X-ray diffraction technique.

10.
Nano Lett ; 18(3): 1758-1763, 2018 03 14.
Artigo em Inglês | MEDLINE | ID: mdl-29397745

RESUMO

Rechargeable aqueous zinc-ion batteries are highly desirable for grid-scale applications due to their low cost and high safety; however, the poor cycling stability hinders their widespread application. Herein, a highly durable zinc-ion battery system with a Na2V6O16·1.63H2O nanowire cathode and an aqueous Zn(CF3SO3)2 electrolyte has been developed. The Na2V6O16·1.63H2O nanowires deliver a high specific capacity of 352 mAh g-1 at 50 mA g-1 and exhibit a capacity retention of 90% over 6000 cycles at 5000 mA g-1, which represents the best cycling performance compared with all previous reports. In contrast, the NaV3O8 nanowires maintain only 17% of the initial capacity after 4000 cycles at 5000 mA g-1. A single-nanowire-based zinc-ion battery is assembled, which reveals the intrinsic Zn2+ storage mechanism at nanoscale. The remarkable electrochemical performance especially the long-term cycling stability makes Na2V6O16·1.63H2O a promising cathode for a low-cost and safe aqueous zinc-ion battery.

11.
ACS Appl Mater Interfaces ; 10(8): 7201-7207, 2018 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-29405692

RESUMO

Constructing novel heterostructures has great potential in tuning the physical/chemical properties of functional materials for electronics, catalysis, as well as energy conversion and storage. In this work, heterostructured Bi2S3-Bi2O3 nanosheets (BS-BO) have been prepared through an easy water-bath approach. The formation of such unique BS-BO heterostructures was achieved through a controllable thioacetamide-directed surfactant-assisted reaction process. Bi2O3 sheets and Bi2S3 sheets can be also prepared through simply modifying the synthetic recipe. When employed as the sodium-ion battery anode material, the resultant BS-BO displays a reversible capacity of ∼630 mA h g-1 at 100 mA g-1. In addition, the BS-BO demonstrates improved rate capability and enhanced cycle stability compared to its Bi2O3 sheets and Bi2S3 sheets counterparts. The improved electrochemical performance can be ascribed to the built-in electric field in the BS-BO heterostructure, which effectively facilitates the charge transport. This work would shed light on the construction of novel heterostructures for high-performance sodium-ion batteries and other energy-related devices.

12.
Chem Commun (Camb) ; 54(12): 1469-1472, 2018 Feb 11.
Artigo em Inglês | MEDLINE | ID: mdl-29355857

RESUMO

A stepwise chelation-etching approach to synthesize carbon-confined ultrafine SnO2 nanoparticles was developed via conformal coating with polydopamine and chelation-etching with ethylenediaminetetraacetic acid (EDTA). EDTA plays a crucial role in the ordered removal of cobalt and tin. The obtained composite exhibits superior sodium storage performance.

13.
Nano Lett ; 17(12): 7773-7781, 2017 12 13.
Artigo em Inglês | MEDLINE | ID: mdl-29131634

RESUMO

Earth-abundant metal-based nanostructured materials have been widely studied for potential energy conversion and storage. However, controlled synthesis of functional nanostructures with high electron conductivity, high reaction activity, and structural stability is still a formidable challenge for further practical applications. Herein, for the first time, we develop a facile, efficient, and general method for the oriented synthesis of precise carbon-confined nanostructures by low-pressure vapor superassembly of a thin metal-organic framework (MOF) shell and subsequent controlled pyrolysis. The selected nanostructured metal oxide precursors not only act as metal ion sources but also orient the superassembly of gaseous organic ligands through the coordination reactions under the low-pressure condition, resulting in the formation of a tunable MOF shell on their surfaces. This strategy is further successfully extended to obtain various precise carbon-confined nanostructures with diverse compositions and delicate morphologies. Notably, these as-prepared carbon-confined architectures exhibit outstanding electrochemical performances in water splitting and lithium storage. The remarkable performances are mainly attributed to the synergistic effect from appropriate chemical compositions and stable carbon-confined structures. This synthetic approach and proposed mechanism open new avenues for the development of functional nanostructured materials in many frontier fields.

14.
ACS Appl Mater Interfaces ; 9(49): 42717-42722, 2017 Dec 13.
Artigo em Inglês | MEDLINE | ID: mdl-29155554

RESUMO

Aqueous zinc-ion batteries attract increasing attention due to their low cost, high safety, and potential application in stationary energy storage. However, the simultaneous realization of high cycling stability and high energy density remains a major challenge. To tackle the above-mentioned challenge, we develop a novel Zn/V2O5 rechargeable aqueous hybrid-ion battery system by using porous V2O5 as the cathode and metallic zinc as the anode. The V2O5 cathode delivers a high discharge capacity of 238 mAh g-1 at 50 mA g-1. 80% of the initial discharge capacity can be retained after 2000 cycles at a high current density of 2000 mA g-1. Meanwhile, the application of a "water-in-salt" electrolyte results in the increase of discharge platform from 0.6 to 1.0 V. This work provides an effective strategy to simultaneously enhance the energy density and cycling stability of aqueous zinc ion-based batteries.

15.
Nanoscale ; 9(46): 18216-18222, 2017 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-29164220

RESUMO

Soft carbon, which possesses the advantages of low cost and considerable potassium storage capacity, has been widely studied as an anode in K-ion batteries (KIBs). Herein, we constructed a novel polycrystalline semi-hollow microrods-structured soft carbon as an anode in KIBs, which exhibited both high capacity and excellent cycling stability.

16.
Nat Commun ; 8(1): 460, 2017 09 06.
Artigo em Inglês | MEDLINE | ID: mdl-28878210

RESUMO

The abundance of sodium resources indicates the potential of sodium-ion batteries as emerging energy storage devices. However, the practical application of sodium-ion batteries is hindered by the limited electrochemical performance of electrode materials, especially at the anode side. Here, we identify alkaline earth metal vanadates as promising anodes for sodium-ion batteries. The prepared calcium vanadate nanowires possess intrinsically high electronic conductivity (> 100 S cm-1), small volume change (< 10%), and a self-preserving effect, which results in a superior cycling and rate performance and an applicable reversible capacity (> 300 mAh g-1), with an average voltage of ∼1.0 V. The specific sodium-storage mechanism, beyond the conventional intercalation or conversion reaction, is demonstrated through in situ and ex situ characterizations and theoretical calculations. This work explores alkaline earth metal vanadates for sodium-ion battery anodes and may open a direction for energy storage.The development of suitable anode materials is essential to advance sodium-ion battery technologies. Here the authors report that alkaline earth metal vanadates are promising candidates due to the favorable electrochemical properties and interesting sodium-storage mechanism.

17.
Chem Commun (Camb) ; 53(59): 8284-8287, 2017 Jul 20.
Artigo em Inglês | MEDLINE | ID: mdl-28696444

RESUMO

A unique carbon-confined metal oxide cube-in-tube nanostructure is synthesized by a facile precursor-modified electrospinning method with subsequent pyrolysis. This nanostructure has a partly graphitized carbon layer with manganese oxide nanoparticles embedded as the tube and amorphous CoSnO3 hollow cubes uniformly distributed inside the tube. As a lithium-ion battery anode, this architecture exhibits a high reversible discharge capacity and rate capability.

18.
J Am Chem Soc ; 139(24): 8212-8221, 2017 06 21.
Artigo em Inglês | MEDLINE | ID: mdl-28541686

RESUMO

Carbon nanotubes (CNTs) are of great interest for many potential applications because of their extraordinary electronic, mechanical and structural properties. However, issues of chaotic staking, high cost and high energy dissipation in the synthesis of CNTs remain to be resolved. Here we develop a facile, general and high-yield strategy for the oriented formation of CNTs from metal-organic frameworks (MOFs) through a low-temperature (as low as 430 °C) pyrolysis process. The selected MOF crystals act as a single precursor for both nanocatalysts and carbon sources. The key to the formation of CNTs is obtaining small nanocatalysts with high activity during the pyrolysis process. This method is successfully extended to obtain various oriented CNT-assembled architectures by modulating the corresponding MOFs, which further homogeneously incorporate heteroatoms into the CNTs. Specifically, nitrogen-doped CNT-assembled hollow structures exhibit excellent performances in both energy conversion and storage. On the basis of experimental analyses and density functional theory simulations, these superior performances are attributed to synergistic effects between ideal components and multilevel structures. Additionally, the appropriate graphitic N doping and the confined metal nanoparticles in CNTs both increase the densities of states near the Fermi level and reduce the work function, hence efficiently enhancing its oxygen reduction activity. The viable synthetic strategy and proposed mechanism will stimulate the rapid development of CNTs in frontier fields.

19.
Nano Lett ; 17(1): 544-550, 2017 01 11.
Artigo em Inglês | MEDLINE | ID: mdl-27959573

RESUMO

K-ion battery (KIB) is a new-type energy storage device that possesses potential advantages of low-cost and abundant resource of K precursor materials. However, the main challenge lies on the lack of stable materials to accommodate the intercalation of large-size K-ions. Here we designed and constructed a novel earth abundant Fe/Mn-based layered oxide interconnected nanowires as a cathode in KIBs for the first time, which exhibits both high capacity and good cycling stability. On the basis of advanced in situ X-ray diffraction analysis and electrochemical characterization, we confirm that interconnected K0.7Fe0.5Mn0.5O2 nanowires can provide stable framework structure, fast K-ion diffusion channels, and three-dimensional electron transport network during the depotassiation/potassiation processes. As a result, a considerable initial discharge capacity of 178 mAh g-1 is achieved when measured for KIBs. Besides, K-ion full batteries based on interconnected K0.7Fe0.5Mn0.5O2 nanowires/soft carbon are assembled, manifesting over 250 cycles with a capacity retention of ∼76%. This work may open up the investigation of high-performance K-ion intercalated earth abundant layered cathodes and will push the development of energy storage systems.

20.
Front Plant Sci ; 8: 2117, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29312383

RESUMO

Small peptides secreted to the extracellular matrix control many aspects of the plant's physiological activities which were identified in Arabidopsis thaliana, called ATSPs. Here, we isolated and characterized the small peptide gene Bna.SP6 from Brassica napus. The BnaC.SP6 promoter was cloned and identified. Promoter deletion analysis suggested that the -447 to -375 and -210 to -135 regions are crucial for the silique septum and pollen expression of BnaC.SP6, respectively. Furthermore, the minimal promoter region of p158 (-210 to -52) was sufficient for driving gene expression specifically in pollen and highly conserved in Brassica species. In addition, BnaA.bZIP1 was predominantly expressed in anthers where BnaC.SP6 was also expressed, and was localized to the nuclei. BnaA.bZIP1 possessed transcriptional activation activity in yeast and protoplast system. It could specifically bind to the C-box in p158 in vitro, and negatively regulate p158 activity in vivo. BnaA.bZIP1 functions as a transcriptional repressor of BnaC.SP6 in pollen activity. These results provide novel insight into the transcriptional regulation of BnaC.SP6 in pollen activity and the pollen/anther-specific promoter regions of BnaC.SP6 may have their potential agricultural application for new male sterility line generation.

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