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1.
Small ; : e1907645, 2020 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-32141157

RESUMO

Polyanion-type phosphate materials are highly promising cathode candidates for next-generation batteries due to their excellent structural stability during cycling; however, their poor conductivity has impeded their development. Isostructural and multivalent anion substitution combined with carbon coating is proposed to greatly improve the electrochemical properties of phosphate cathode in sodium-ion batteries (SIBs). Specifically, multivalent tetrahedral SiO4 4- substitute for PO4 3- in Na3 V2 (PO4 )3 (NVP) lattice, preparing the optimal Na3.1 V2 (PO4 )2.9 (SiO4 )0.1 with high-rate capability (delivering a high capacity of 82.5 mAh g-1 even at 20 C) and outstanding cyclic stability (≈98% capacity retention after 500 cycles at 1 C). Theoretical calculation and experimental analyses reveal that the anion-substituted Na3.1 V2 (PO4 )2.9 (SiO4 )0.1 reduces the bandgap of NVP lattice and enhanced its structural stability, Na+ -diffusion kinetics and electronic conductivity. This strategy of multivalent and isostructural anion substitution chemistry provides a new insight to develop advanced phosphate cathodes.

2.
Chemistry ; 2020 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-32196795

RESUMO

The phosphate cathode materials are practical in sodium-ion batteries (SIBs) owing to their high stability and long-term cycle life. In this work, temperature-dependent properties of phosphate cathode Na 3 V 2 (PO 4 ) 2 O 2 F (abbr. NVPOF) are studied in a wide temperature range of -25 ~ 55°C. As cycling at general temperature (above 0°C), the NVPOF cathode can remain excellent charge-discharge performance, and the rate capability is noteworthy, indicating that NVPOF is a competitive candidate for temperature-adaptive cathode of SIBs. When the temperature decreases below 0°C, the performance of the cell degrades, which may derive from the electrolyte and Na electrode, basing on the study of ionic conductivity and electrode kinetics. It proposes a new breakthrough point for developing the SIBs with high-performance in a wide temperature range for the advanced power systems.

3.
ACS Appl Mater Interfaces ; 11(51): 47886-47893, 2019 Dec 26.
Artigo em Inglês | MEDLINE | ID: mdl-31797668

RESUMO

The intrinsic charge-transfer property bears the primary responsibility for the sluggish redox kinetics of the common electrode materials, especially operated at low temperatures. Herein, we report the crafting of homogeneously confined Fe7Se8 nanoparticles with a well-defined graphitic carbon matrix that demonstrate a highly efficient charge-transfer system in a designed natural coral-like structure (cl-Fe7Se8@C). Notably, the intricate architecture as well as highly conductive peculiarity of C concurrently satisfy the demands of achieving fast ionic/electrical conductivities for both Li/Na-ion batteries in a wide temperature range. For example, when cl-Fe7Se8@C is employed as the anode material to assemble full batteries with the cathode of Na3V2(PO4)2O2F (NVPOF), decent capacities of 323.1 and 175.9 mA h g-1 can be acquired at temperatures of 25 and -25 °C, respectively. This work is significant for further developing potential anode materials for advanced energy storage and conversion under low-temperature conditions.

4.
ACS Appl Mater Interfaces ; 11(27): 24192-24197, 2019 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-31188554

RESUMO

Na super ionic conductor (NASICON)-structured materials have evolved to play many critical roles in battery systems because of their three-dimensional framework structures. Here, by coupling NASICON-structured Na3V2(PO4)2O2F cathodes and Na3V2(PO4)3 anodes, an asymmetric Na-ion-based full cell exhibits two flat voltage plateaus at about 2.3 and 1.9 V and a high capacity of 101 mA h/g. Moreover, an all-solid-state Na-ion battery has been further enabled by the concept of using all NASICON-structured materials, including cathodes, anodes, and electrolytes (Na5YSi4O12), which delivers a high output voltage. Importantly, the full cell displays high safety without using a flammable organic liquid electrolyte and superior structure stability with all NASICON-structured materials.

5.
Adv Mater ; 31(4): e1804766, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30489656

RESUMO

Conventional ion batteries utilizing metallic ions as the single charge carriers are limited by the insufficient abundance of metal resources. Although supercapacitors apply both cations and anions to store energy through absorption and/or Faradic reactions occurring at the interfaces of the electrode/electrolyte, the inherent low energy density hinders its application. The graphite-cathode-based dual-ion battery possesses a higher energy density due to its high working potential of nearly 5 V. However, such a battery configuration suffers from severe electrolyte decomposition and exfoliation of the graphite cathode, rendering an inferior cycle life. Herein, a new surface-modification strategy is developed to protect the graphite cathode from the anion salvation effect and the deposition derived from electrolyte decomposition by generating an artificial solid electrolyte interphase (SEI). Such SEI-modified graphite exhibits superior cycling stability with 96% capacity retention after 500 cycles under 200 mA g-1 at the upper cutoff voltage of 5.0 V, which is much improved compared with the pristine graphite electrode. Through several ex situ studies, it is revealed that the artificial SEI greatly stabilizes the interfaces of the electrode/electrolyte after reconstruction and gradual establishment of the optimal anion-transport path. The findings shed light on a new avenue toward promoting the performance of the dual-ion battery (DIB) and hence to make it practical finally.

6.
ACS Appl Mater Interfaces ; 10(43): 36902-36909, 2018 Oct 31.
Artigo em Inglês | MEDLINE | ID: mdl-30278127

RESUMO

Due to the Earth's scarcity of lithium, replacing lithium with earth-abundant and low-cost sodium for sodium-ion batteries (SIBs) has recently become a promising substitute for lithium-ion batteries. However, the shortage of appropriate anode materials limits the development of SIBs. Here, a dual-carbon conductive network enhanced GeP5 (GeP5/acetylene black/partially reduced graphene oxide sheets (GeP5/AB/p-rGO)) composite is successfully prepared by a facile ball milling method. The dual-carbon network not only provides more transport pathways for electrons but also relaxes the huge volume change of the electrode material during the charge/discharge process. Compared with only AB- or GO-modified GeP5 (GeP5/AB or GeP5/GO) composite, the GeP5/AB/p-rGO composite shows a superior sodium storage performance with an excellent rate and cycle performance. It delivers a high reversible capacity of 597.5 and 175 mAh/g at the current density of 0.1 and 5.0 A/g, respectively. Furthermore, at the current density of 0.5 A/g, the GeP5/AB/p-rGO composite shows the reversible capacity of 400 mAh/g after 50 cycles with a little capacity attenuation. All above results prove that the GeP5/AB/p-rGO composite has a good prospect of application as an anode material for SIBs.

7.
ACS Appl Mater Interfaces ; 10(40): 34272-34282, 2018 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-30222306

RESUMO

As a promising cathode material of sodium-ion battery, P2-type Na2/3Ni1/3Mn2/3O2 (NNMO) possesses a theoretically high capacity and working voltage to realize high energy storage density. However, it still suffers from poor cycling stability mainly incurred by the undesirable P2-O2 phase transition. Herein, the electrochemically active Fe3+ ions are introduced into the lattice of NNMO, forming Na2/3Ni1/3Mn2/3- xFe xO2 ( x = 0, 1/24, 1/12, 1/8, 1/6) to effectively stabilize the P2-type crystalline structure. In such Fe-substituted materials, both Ni2+/Ni4+ and Fe3+/Fe4+ couples take part in the redox reactions, and the P2-O2 phase transition is well restrained during cycling, as verified by ex situ X-ray diffraction. As a result, the optimized Na2/3Ni1/3Mn7/12Fe1/12O2 (1/12-NNMF) has a long-term cycling stability with the fading rate of 0.05% per cycle over 300 cycles at 5 C. Furthermore, the 1/12-NNMF delivers excellent rate capabilities (65 mA h g-1 at 25 C) and superior low-temperature performance (the capacity retention of 94% at -25 °C after 80 cycles) owing to the enhanced Na diffusion upon Fe doping, which is deduced by the studies of electrode kinetics. More significantly, the 1/12-NNMF also displays remarkable sodium-ion full-cell properties when merged with an LS-Sb@G anode, thus implying the possibility of their practical application.

8.
Nanoscale ; 10(19): 9218-9225, 2018 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-29726554

RESUMO

In order to develop promising anode materials for sodium-ion batteries (SIBs), a novel pie-like FeS@C (P-FeS@C) nanohybrid, in which all ultrasmall FeS nanocrystals (NCs) are completely embedded into the carbon network and sealed by a protective carbon shell, has been prepared. The unique pie-like structure can effectively speed up the kinetics of electrode reactions, while the carbon shell stabilizes the FeS NCs inside. Studies show that the electrochemical reaction processes of P-FeS@C electrodes are dominated by the pseudocapacitive behavior, leading to an ultrafast Na+-insertion/extraction reaction. Hence, the prepared P-FeS@C nanohybrid exhibits superior Na-storage properties especially high rate capability in half cells. For example, it can deliver reversible capacities of 555.1 mA h g-1 at 0.2 A g-1 over 150 cycles and about 60.4 mA h g-1 at 80 A g-1 (an ultrahigh current density even higher than that of the capacitor test). Furthermore, an advanced P-FeS@C//Na3V2(PO4)2O2F full cell has been assembled out, which delivers a stable specific capacity of 441.2 mA h g-1 after 80 cycles at 0.5 A g-1 with a capacity retention of 91.8%.

9.
ACS Appl Mater Interfaces ; 10(21): 17903-17910, 2018 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-29717864

RESUMO

Developing a high-performance, low-cost, and safer rechargeable battery is a primary challenge in next-generation electrochemical energy storage. In this work, a quasi-solid-state (QSS) sodium-ion full battery (SIFB) is designed and fabricated. Hard carbon cloth derived from cotton cloth and Na3V2(PO4)2O2F (NVPOF) are employed as the anode and the cathode, respectively, and a sodium ion-conducting gel-polymer membrane is used as both the QSS electrolyte and separator, accomplishing the high energy and power densities in the QSS sodium-ion batteries. The energy density can reach 460 W h kg-1 according to the mass of the cathode materials. Moreover, the fabricated QSS SIFB also exhibits an excellent rate performance (e.g., about 78.1 mA h g-1 specific capacity at 10 C) and a superior cycle performance (e.g., ∼90% capacity retention after 500 cycles at 10 C). These results show that the developed QSS SIFB is a hopeful candidate for large-scale energy storage.

10.
Adv Mater ; 30(21): e1706317, 2018 May.
Artigo em Inglês | MEDLINE | ID: mdl-29611231

RESUMO

Incorporation of N,S-codoped nanotube-like carbon (N,S-NTC) can endow electrode materials with superior electrochemical properties owing to the unique nanoarchitecture and improved kinetics. Herein, α-MnS nanoparticles (NPs) are in situ encapsulated into N,S-NTC, preparing an advanced anode material (α-MnS@N,S-NTC) for lithium-ion/sodium-ion batteries (LIBs/SIBs). It is for the first time revealed that electrochemical α → ß phase transition of MnS NPs during the 1st cycle effectively promotes Li-storage properties, which is deduced by the studies of ex situ X-ray diffraction/high-resolution transmission electron microscopy and electrode kinetics. As a result, the optimized α-MnS@N,S-NTC electrode delivers a high Li-storage capacity (1415 mA h g-1 at 50 mA g-1 ), excellent rate capability (430 mA h g-1 at 10 A g-1 ), and long-term cycling stability (no obvious capacity decay over 5000 cycles at 1 A g-1 ) with retained morphology. In addition, the N,S-NTC-based encapsulation plays the key roles on enhancing the electrochemical properties due to its high conductivity and unique 1D nanoarchitecture with excellent protective effects to active MnS NPs. Furthermore, α-MnS@N,S-NTC also delivers high Na-storage capacity (536 mA h g-1 at 50 mA g-1 ) without the occurrence of such α → ß phase transition and excellent full-cell performances as coupling with commercial LiFePO4 and LiNi0.6 Co0.2 Mn0.2 O2 cathodes in LIBs as well as Na3 V2 (PO4 )2 O2 F cathode in SIBs.

11.
ACS Appl Mater Interfaces ; 10(4): 3581-3589, 2018 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-29303243

RESUMO

A novel core-shell Fe3O4@FeS composed of Fe3O4 core and FeS shell with the morphology of regular octahedra has been prepared via a facile and scalable strategy via employing commercial Fe3O4 as the precursor. When used as anode material for sodium-ion batteries (SIBs), the prepared Fe3O4@FeS combines the merits of FeS and Fe3O4 with high Na-storage capacity and superior cycling stability, respectively. The optimized Fe3O4@FeS electrode shows ultralong cycle life and outstanding rate capability. For instance, it remains a capacity retention of 90.8% with a reversible capacity of 169 mAh g-1 after 750 cycles at 0.2 A g-1 and 151 mAh g-1 at a high current density of 2 A g-1, which is about 7.5 times in comparison to the Na-storage capacity of commercial Fe3O4. More importantly, the prepared Fe3O4@FeS also exhibits excellent full-cell performance. The assembled Fe3O4@FeS//Na3V2(PO4)2O2F sodium-ion full battery gives a reversible capacity of 157 mAh g-1 after 50 cycles at 0.5 A g-1 with a capacity retention of 92.3% and the Coulombic efficiency of around 100%, demonstrating its applicability for sodium-ion full batteries as a promising anode. Furthermore, it is also disclosed that such superior electrochemical properties can be attributed to the pseudocapacitive behavior of FeS shell as demonstrated by the kinetics studies as well as the core-shell structure. In view of the large-scale availability of commercial precursor and ease of preparation, this study provide a scalable strategy to develop advanced anode materials for SIBs.

12.
Adv Mater ; 29(33)2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28639347

RESUMO

Sodium-ion batteries (SIBs) are still confronted with several major challenges, including low energy and power densities, short-term cycle life, and poor low-temperature performance, which severely hinder their practical applications. Here, a high-voltage cathode composed of Na3 V2 (PO4 )2 O2 F nano-tetraprisms (NVPF-NTP) is proposed to enhance the energy density of SIBs. The prepared NVPF-NTP exhibits two high working plateaux at about 4.01 and 3.60 V versus the Na+ /Na with a specific capacity of 127.8 mA h g-1 . The energy density of NVPF-NTP reaches up to 486 W h kg-1 , which is higher than the majority of other cathode materials previously reported for SIBs. Moreover, due to the low strain (≈2.56% volumetric variation) and superior Na transport kinetics in Na intercalation/extraction processes, as demonstrated by in situ X-ray diffraction, galvanostatic intermittent titration technique, and cyclic voltammetry at varied scan rates, the NVPF-NTP shows long-term cycle life, superior low-temperature performance, and outstanding high-rate capabilities. The comparison of Ragone plots further discloses that NVPF-NTP presents the best power performance among the state-of-the-art cathode materials for SIBs. More importantly, when coupled with an Sb-based anode, the fabricated sodium-ion full-cells also exhibit excellent rate and cycling performances, thus providing a preview of their practical application.

13.
ACS Appl Mater Interfaces ; 8(32): 20650-9, 2016 Aug 17.
Artigo em Inglês | MEDLINE | ID: mdl-27454458

RESUMO

As a promising alternative for lithium ion batteries, room-temperature sodium ion batteries (SIBs) have become one significant research frontier of energy storage devices although there are still many difficulties to be overcome. For the moment, the studies still concentrate on the preparation of new electrode materials for SIBs to meet the applicability. Herein, one new P2-Na2/3Ni1/3Mn5/9Al1/9O2 (NMA) cathode material is successfully prepared via a simple and facile liquid-state method. The prepared NMA is layered transition metal oxide, which can keep stable crystal structure during sodiation/desodiation as demonstrated by the ex situ X-ray diffraction, and its electrochemical properties can be further enhanced by connecting the cake-like NMA microparticles with reduced graphene oxide (RGO) using a ball milling method. Electrochemical tests show that the formed RGO-connected NMA (NMA/RGO) can deliver a higher reversible capacity of up to 138 mAh g(-1) at 0.1 C and also exhibit a superior high-rate capabilities and cycling stability in comparison to pure NMA. The much improved properties should be attributed to the reduced particle size and improvement of electrical conductivity and apparent Na(+) diffusion due to RGO incorporation, which is comprehensively verified by the electrochemical technologies of galvanostatic intermittent titration technique, electrochemical impedance spectroscopy and cyclic voltammetry at various scan rate as well as ex-situ X-ray diffraction studies.

14.
Chemistry ; 22(24): 8152-7, 2016 06 06.
Artigo em Inglês | MEDLINE | ID: mdl-27136376

RESUMO

Although graphene oxide (GO) has large interlayer spacing, it is still inappropriate to use it as an anode for sodium-ion batteries (SIBs) because of the existence of H-bonding between the layers and ultralow electrical conductivity which impedes the Na(+) and e(-) transformation. To solve these issues, chemical, thermal, and electrochemical procedures are traditionally employed to reduce GO nanosheets. However, these strategies are still unscalable, consume high amounts of energy, and are expensive for practical application. Here, for the first time, we describe the superior Na storage of unreduced GO by a simple and scalable alkali-metal-ion (Li(+) , Na(+) , K(+) )-functionalized process. The various alkali metals ions, connecting with the oxygen on GO, have played different effects on morphology, porosity, degree of disorder, and electrical conductivity, which are crucial for Na-storage capabilities. Electrochemical tests demonstrated that sodium-ion-functionalized GO (GNa) has shown outstanding Na-storage performance in terms of excellent rate capability and long-term cycle life (110 mAh g(-1) after 600 cycles at 1 A g(-1) ) owing to its high BET area, appropriate mesopore, high degree of disorder, and improved electrical conductivity. Theoretical calculations were performed using the generalized gradient approximation (GGA) to further study the Na-storage capabilities of functionalized GO. These calculations have indicated that the Na-O bond has the lowest binding energy, which is beneficial to insertion/extraction of the sodium ion, hence the GNa has shown the best Na-storage properties among all comparatives functionalized by other alkali metal ions.

15.
ACS Appl Mater Interfaces ; 8(12): 7790-9, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26960386

RESUMO

Graphene incorporation should be one effective strategy to develop advanced electrode materials for a sodium-ion battery (SIB). Herein, the micro/nanostructural Sb/graphene composite (Sb-O-G) is successfully prepared with the uniform Sb nanospheres (∼100 nm) bound on the graphene via oxygen bonds. It is revealed that the in-situ-constructed oxygen bonds play a significant role on enhancing Na-storage properties, especially the ultrafast charge/discharge capability. The oxygen-bond-enhanced Sb-O-G composite can deliver a high capacity of 220 mAh/g at an ultrahigh current density of 12 A/g, which is obviously superior to the similar Sb/G composite (130 mAh/g at 10 A/g) just without Sb-O-C bonds. It also exhibits the highest Na-storage capacity compared to Sb/G and pure Sb nanoparticles as well as the best cycling performance. More importantly, this Sb-O-G anode achieves ultrafast (120 C) energy storage in SIB full cells, which have already been shown to power a 26-bulb array and calculator. All of these superior performances originate from the structural stability of Sb-O-C bonds during Na uptake/release, which has been verified by ex situ X-ray photoelectron spectroscopies and infrared spectroscopies.

16.
Chemistry ; 21(48): 17371-8, 2015 Nov 23.
Artigo em Inglês | MEDLINE | ID: mdl-26481446

RESUMO

A superior Na3 V2 (PO4 )3 -based nanocomposite (NVP/C/rGO) has been successfully developed by a facile carbothermal reduction method using one most-common chelator, disodium ethylenediamintetraacetate [Na2 (C10 H16 N2 O8 )], as both sodium and nitrogen-doped carbon sources for the first time. 2D-reduced graphene oxide (rGO) nanosheets are also employed as highly conductive additives to facilitate the electrical conductivity and limit the growth of NVP nanoparticles. When used as the cathode material for sodium-ion batteries, the NVP/C/rGO nanocomposite exhibits the highest discharge capacity, the best high-rate capabilities and prolonged cycling life compared to the pristine NVP and single-carbon-modified NVP/C. Specifically, the 0.1 C discharge capacity delivered by the NVP/C/rGO is 116.8 mAh g(-1) , which is obviously higher than 106 and 112.3 mAh g(-1) for the NVP/C and pristine NVP respectively; it can still deliver a specific capacity of about 80 mAh g(-1) even at a high rate up to 30 C; and its capacity decay is as low as 0.0355 % per cycle when cycled at 0.2 C. Furthermore, the electrochemical impedance spectroscopy was also implemented to compare the electrode kinetics of all three NVP-based cathodes including the apparent Na diffusion coefficients and charge-transfer resistances.

17.
Chem Commun (Camb) ; 51(80): 14848-51, 2015 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-26344149

RESUMO

A new cathode material composed of romanechite-structured Na(0.31)MnO(1.9) nanofibers is developed for sodium-ion batteries for the first time. It can deliver a Na-uptake capacity of >100 mA h g(-1) with a superior high-rate capability and good cycling performance in the voltage range of 2-4.5 V vs. Na(+)/Na, and exhibit the unique ability of fast charging with the normal discharge rate.

18.
Zhong Yao Cai ; 37(2): 266-9, 2014 Feb.
Artigo em Chinês | MEDLINE | ID: mdl-25095349

RESUMO

OBJECTIVE: To study the chemical constituents from Dichotella gemmacea. METHODS: Chemical constituents were isolated by silica gel and Sephadex LH-20 column chromatography. The structures of the isolated compounds were elucidated through spectroscopic analysis. RESULTS: Eight compounds were identified as fragilide J(I), junceelldide D(II), junceellin A (IlI), juncin P(IV), dichotellides A (V), cerevisterol (VI), 1,2-diphenyldiselane (VII) and 5H-pyrido[4,3-b] indole (VIII). CONCLUSION: Compounds VI, VII and VIII are isolated from Dichotella gemmacea for the first time.


Assuntos
Antozoários/química , Carbolinas/química , Fitosteróis/química , Animais , Carbolinas/isolamento & purificação , China , Diterpenos/química , Diterpenos/isolamento & purificação , Cromatografia Gasosa-Espectrometria de Massas , Estrutura Molecular , Oceanos e Mares , Fitosteróis/isolamento & purificação
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