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1.
Small ; 20(14): e2306272, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-37988649

RESUMO

Precise control of pore volume and size of carbon nanoscale materials is crucial for achieving high capacity and rate performances of charge/discharge. In this paper, starting from the unique mechanism of the role of In, Zn combination, and carboxyl functional groups in the formation of the lumen and pore size, the composition of InZn-MIL-68 is regulated to precisely tune the diameter and wall pore size of the hollow carbon tubes. The hollow carbon nanotubes (CNT) with high-capacity storage and fast exchange of Na+ ions and charges are prepared. The CNT possess ultra-high specific capacitance and ultra-long cycle life and also offer several times higher Na+ ion storage capacity and rate performance than the existing CNTs. Density functional theory calculations and tests reveal that these superior characteristics are attributed to the spacious hollow structure, which provides sufficient space for Na+ storage and the tube wall's distinctive porosity of tube wall as well as open ends for facilitating Na+ rapid desorption. It is believed that precise control of sub-nanopore volume and pore size by tuning the composition of the carbon materials derived from bimetallic metal-organic frameworks (MOFs) will establish the basis for the future development of high-energy density and high-power density supercapacitors and batteries.

2.
Chemistry ; 28(2): e202103275, 2022 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-34779065

RESUMO

It is a great challenge to fabricate highly efficient pH-universal electrocatalysts for oxygen reduction reaction (ORR). Herein, a facile strategy, which includes coating the Fe modified ZIF8 on Cu foil and in situ pyrolysis to evaporate and dope Cu into the MOF derived carbon, is developed to fabricate Fe/Cu-N co-doped carbon material (Cu/Fe-NC). Profiting from the modulated electron distribution and textual properties, well-designed Cu/Fe-NC exhibits superior half-wave potential (E1/2 ) of 0.923 V in alkaline, 0.757 V in neutral and comparable 0.801 V in acid electrolytes, respectively. Furthermore, the ultralow peroxides yield of ORR demonstrates the high selectivity of Cu/Fe-NC in full pH scale electrolytes. As expected, the self-made alkaline and neutral zinc-air batteries equipped with Cu/Fe-NC cathode display excellent discharge voltages, outstanding peak power densities and remarkable stability. This work opens a new way to fabricate highly efficient and pH-universal electrocatalysts for ORR through strategy of Fe/Cu-N co-doping, Cu foil evaporation and carbon defects capture.

3.
Dalton Trans ; 53(10): 4662-4670, 2024 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-38358364

RESUMO

In order to reduce the high polarization caused by the hysteresis effect of O2 diffusion and boost the power density of oxygen cathodes under a transient heavy load, an Al-MOF-derived porous carbon-modified Pt/C catalyst is proposed as a new capacitive ORR catalyst to construct super fuel cells (SFCs) via an ORR + EDLC dual-discharge parallel process. Herein, a capacitive porous carbon material (BTCC-2) with a large specific surface area (SSA) and high graphitization was synthesized via one-step carbonization of Al-MOFs (Al-BTC). After compounding BTCC-2 with commercial Pt/C catalysts, electrochemical tests were performed and revealed that the composite with 40% BTCC-2 provided the highest transient discharge performance. Moreover, the composite had a higher onset potential and limiting current density (5.236 mA cm-2) than Pt/C and a half-wave potential (0.833 V) comparable to that of Pt/C. The abundant pore structure and large surface of BTCC-2 greatly increased the interaction between oxygen and the catalyst surface. Besides, the contained BTCC-2 serve as a significant power bank to remarkably buffer and relieve the rapidly decreasing output voltage under an instant heavy load owing to the oxygen deficiencies in a Zn-air battery through the ORR + EDLC dual-parallel-discharge process. The proposed SFC design has potential as a universal method to solve the sluggish ORR process and provide high transient power density for fuel cell-driven vehicles.

4.
Dalton Trans ; 53(3): 1121-1131, 2024 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-38099811

RESUMO

The use of a methanesulfonic acid (MSA) electrolytic system is recommended as a green method for hydrometallurgical recovery of metallic Pb from waste lead-acid batteries (LABs), contributing to the sustainable protection of the ecosystem. Nevertheless, the system's high energy consumption is a current issue due to the substantial overpotential of the oxygen evolution reaction (OER) and competitive anodic oxidation of Pb2+. Herein, we propose an IrFe/nitrogen-doped pyrolytic carbon black (IrFe/NCBp) composite as a novel OER catalyst for the MSA electrolytic system, which demonstrates advanced OER catalytic efficiency and selectivity for H2O oxidation. This can be ascribed to the catalyst's thoughtful design, which enhances the number and uniformity of Ir and Fe species via increasing the specific surface area and employing NCBp as a sustainable substrate. The optimized IrFe/NCBp composite exhibits superior OER performance, with a low 252 mV@10 mA cm-2 overpotential and a 62 mV dec-1 Tafel slope, and excellent durability in a 1 M MSA electrolyte for 30 h operation compared to commercial Ir/C. In contrast to carbon paper (CP) and commercial Ir/C anodes, the anodic reaction of IrFe/NCBp is primarily OER-driven (97%) in 1 M MSA and 0.2 M Pb2+ electrolyte for Pb recovery. This effectively circumvents the high potential oxidation of Pb2+ into PbO2, reducing the electrolytic voltage to 488 kWh for the recovery of 1 ton Pb metal. This work provides a green, low-carbon footprint solution for the MSA electrolytic system, thereby promoting the commercialization of the hydrometallurgical Pb recovery.

5.
Waste Manag ; 184: 52-62, 2024 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-38795540

RESUMO

The direct recovery of high-purity PbO from spent lead paste without a pre-desulfation process has significant industrial promise. Herein, we propose a recyclable, ultra-fast, and high value-added closed-loop of high-purity PbO recovery process by intensive multidentate coordination of histidine with crude 2PbO·PbSO4 by a rotating liquid-film (RLF) reactor and CO2 carbonation-dissociation. Parameter optimizations and kinetic calculations show the leaching time is shortened from 40 min to 60 s with 99.14 % leaching rate and 99.99 % PbO purity by internal diffusion control, where the RLF reactor promotes mass transfer and reaction rates by instantly renewing the surface of crude 2PbO·PbSO4. Furthermore, all 5 batches reveal that the separation of SO42- ions from the regenerated mother liquid with Ba(OH)2 significantly improves the recycling rate of the mother liquid and high-purity PbO product. This new strategy reveals a bright prospect of a highly efficient, high value-added, and environmentally friendly recycling route for solid waste resources.


Assuntos
Fontes de Energia Elétrica , Chumbo , Óxidos , Reciclagem , Reciclagem/métodos , Chumbo/química , Óxidos/química , Gerenciamento de Resíduos/métodos , Cinética
6.
Materials (Basel) ; 17(7)2024 Apr 04.
Artigo em Inglês | MEDLINE | ID: mdl-38612173

RESUMO

Rechargeable aqueous zinc-ion batteries have attracted a lot of attention owing to their cost effectiveness and plentiful resources, but less research has been conducted on the aspect of high volumetric energy density, which is crucial to the space available for the batteries in practical applications. In this work, highly crystalline V2O5 microspheres were self-assembled from one-dimensional V2O5 nanorod structures by a template-free solvothermal method, which were used as cathode materials for zinc-ion batteries with high performance, enabling fast ion transport, outstanding cycle stability and excellent rate capability, as well as a significant increase in tap density. Specifically, the V2O5 microspheres achieve a reversible specific capacity of 414.7 mAh g-1 at 0.1 A g-1, and show a long-term cycling stability retaining 76.5% after 3000 cycles at 2 A g-1. This work provides an efficient route for the synthesis of three-dimensional materials with stable structures, excellent electrochemical performance and high tap density.

7.
Materials (Basel) ; 17(8)2024 Apr 11.
Artigo em Inglês | MEDLINE | ID: mdl-38673105

RESUMO

Electrosynthesis of H2O2 via both pathways of anodic two-electron water oxidation reaction (2e-WOR) and cathodic two-electron oxygen reduction reaction (2e-ORR) in a diaphragm-free bath can not only improve the generation rate and Faraday efficiency (FE), but also simplify the structure of the electrolysis bath and reduce the energy consumption. The factors that may affect the efficiency of H2O2 generation in coupled electrolytic systems have been systematically investigated. A piece of fluorine-doped tin oxide (FTO) electrode was used as the anode, and in this study, its catalytic performance for 2e-WOR in Na2CO3/NaHCO3 and NaOH solutions was compared. Based on kinetic views, the generation rate of H2O2 via 2e-WOR, the self-decomposition, and the oxidative decomposition rate of the generated H2O2 during electrolysis in carbonate electrolytes were investigated. Furthermore, by choosing polyethylene oxide-modified carbon nanotubes (PEO-CNTs) as the catalyst for 2e-ORR and using its loaded electrode as the cathode, the coupled electrolytic systems for H2O2 generation were set up in a diaphragm bath and in a diaphragm-free bath. It was found that the generated H2O2 in the electrolyte diffuses and causes oxidative decomposition on the anode, which is the main influent factor on the accumulated concentration in H2O2 in a diaphragm-free bath.

8.
Adv Mater ; 36(1): e2308989, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37966064

RESUMO

Pursuing high power density with low platinum catalysts loading is a huge challenge for developing high-performance fuel cells (FCs). Herein, a new super fuel cell (SFC) is proposed with ultrahigh output power via specific electric double-layer capacitance (EDLC) + oxygen reduction reaction (ORR) parallel discharge, which is achieved using the newly prepared catalyst, single-atomic platinum on bimetallic metal-organic framework (MOF)-derived hollow porous carbon nanorods (PtSA /HPCNR). The PtSA-1.74 /HPCNR-based SFC has a 3.4-time higher transient specific power density and 13.3-time longer discharge time with unique in situ self-charge and energy storage ability than 20% Pt/C-based FCs. X-ray absorption fine structure, aberration-corrected high-angle annular dark-field scanning transmission electron microscope, and density functional theory calculations demonstrate that the synergistic effect of Pt single-atoms anchored on carbon defects significantly boosts its electron transfer, ORR catalytic activity, durability, and rate performance, realizing rapid " ORR+EDLC" parallel discharge mechanism to overcome the sluggish ORR process of traditional FCs. The promising SFC leads to a new pathway to boost the power density of FCs with extra-low Pt loading.

9.
iScience ; 27(4): 109553, 2024 Apr 19.
Artigo em Inglês | MEDLINE | ID: mdl-38623338

RESUMO

Electrocatalytic generation of H2O2 via the 2-electron pathway of oxygen reduction reaction (2e-ORR) is an attractive technology compared to the anthraquinone process due to convenience and environmental friendliness. However, catalysts with excellent selectivity and high activity for 2e-ORR are necessary for practical applications. Reported here is a catalyst comprising boron-doped porous carbon hollow spheres (B-PCHSs) prepared using the hard template method coupled with borate transesterification. In an alkali electrolyte, the selectivity of B-PCHS for 2e-ORR above 90% in range of 0.4-0.7 VRHE and an onset potential of 0.833 V was obtained. Meanwhile, the generation rate of H2O2 reached 902.48 mmol h-1 gcat-1 at 0.4 VRHE under 59.13 mA cm-2 in batch electrolysis. The excellent catalytic selectivity of B-PCHS for 2e-ORR originates from the boron element, and the catalytic activity of B-PCHS for H2O2 generation is contributed to the morphology of porous hollow spheres, which facilitates mass transfer processes.

10.
Materials (Basel) ; 16(11)2023 May 26.
Artigo em Inglês | MEDLINE | ID: mdl-37297131

RESUMO

Nickel-iron-layered double hydroxide (NiFeLDH) is one of the promising catalysts for the oxygen evolution reaction (OER) in alkaline electrolytes, but its conductivity limits its large-scale application. The focus of current work is to explore low-cost, conductive substrates for large-scale production and combine them with NiFeLDH to improve its conductivity. In this work, purified and activated pyrolytic carbon black (CBp) is combined with NiFeLDH to form an NiFeLDH/A-CBp catalyst for OER. CBp not only improves the conductivity of the catalyst but also greatly reduces the size of NiFeLDH nanosheets to increase the activated surface area. In addition, ascorbic acid (AA) is introduced to enhance the coupling between NiFeLDH and A-CBp, which can be evidenced by the increase of Fe-O-Ni peak intensity in FTIR measurement. Thus, a lower overvoltage of 227 mV and larger active surface area of 43.26 mF·cm-2 are achieved in 1 M KOH solution for NiFeLDH/A-CBp. In addition, NiFeLDH/A-CBp shows good catalytic performance and stability as the anode catalyst for water splitting and Zn electrowinning in alkaline electrolytes. In Zn electrowinning with NiFeLDH/A-CBp, the low cell voltage of 2.08 V at 1000 A·m-2 results in lower energy consumption of 1.78 kW h/KgZn, which is nearly half of the 3.40 kW h/KgZn of industrial electrowinning. This work demonstrates the new application of high-value-added CBp in hydrogen production from electrolytic water and zinc hydrometallurgy to realize the recycling of waste carbon resources and reduce the consumption of fossil resources.

11.
ACS Appl Mater Interfaces ; 15(16): 20089-20099, 2023 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-37043423

RESUMO

Aqueous zinc-ion batteries are considered as an ideal substitute for lithium-ion batteries due to their abundant resource storage, high safety, and low price. However, zinc anodes exhibit poor reversibility and cyclic stability in most conventional aqueous electrolytes. Herein, an environmentally friendly Zn(CH3SO3)2 electrolyte is proposed to solve the problems of common aqueous electrolytes. The bulky CH3SO3- anions can regulate the solvation structure of Zn2+ by replacing some water molecules in the primary solvation sheath of Zn2+, thus slowing the hydrogen evolution side reactions and formation of zinc dendrite. Additionally, the changing solvation structure weakens the bonding between Zn2+ and the surrounding water molecules, which is conducive to the transport and charge transfer of Zn2+, thus improving the battery capacity. In the Zn(CH3SO3)2 electrolyte, Zn plating/stripping exhibits a high Coulombic efficiency of >98% and long-term cyclic stability over 800 h. The specific capacity of the assembled Zn//V2O5 cell in 3 mol L-1 Zn(CH3SO3)2 reaches 350 mA h g-1 at 0.1 A g-1, much higher than that in the ZnSO4 electrolyte (213 mA h g-1). In conclusion, this work offers insights into the exploration of advanced green electrolyte systems for zinc-ion batteries.

12.
ACS Appl Mater Interfaces ; 15(12): 15439-15448, 2023 Mar 29.
Artigo em Inglês | MEDLINE | ID: mdl-36921252

RESUMO

High-performance rechargeable oxygen electrodes are key devices for realizing high-specific-energy batteries, including zinc-air and lithium-air batteries. However, these batteries have severe problems of premature decay in energy efficiency by serious corrosion, wide charge-discharge gap, and catalyst peeling off. Herein, we propose a "smart dual-oxygen electrode", which is composed of an intelligent switch control module + heterostructured Fe1Ni3-LDH/PNCNF OER catalysis electrode layer + ion conductive | electronic insulating membrane + Pt/C ORR catalysis electrode layer, where OER and ORR layers are automatically switched by the intelligent switch control module as required. This smart dual-oxygen electrode offers an ultralow energy efficiency decay rate of 0.0067% after 300 cycles during cycling, much lower than that of the commercial Pt/C electrode (1.82%). The assembled rechargeable zinc-air battery (RZAB) displays a super narrow voltage gap and achieves a high energy efficiency of 71.7%, far higher than that of the existing RZABs (about 50%). Therefore, this strategy provides a complete solution for designing various high-performance metal-air secondary batteries.

13.
Adv Sci (Weinh) ; 10(34): e2304863, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37867231

RESUMO

The new low-cost clean pre-desulfation technology is very important in pyrometallurgy and hydrometallurgy. However, traditional reactors have low space-time yield and desulfation rate, resulting in high energy consumption and SO2 emissions in the industrial desulfation processes. Herein, dual rotating liquid film reactors (RLFRs) and lime are proposed to construct a recyclable, ultra-fast, and value-added desulfation method. Parameter optimization and kinetic calculations prove that the above reactions are controlled by internal diffusion, revealing that RLFR promotes the mass transfer and reaction rate. The new process greatly shortens the desulfation time of lead paste from 40 min to 10 s with a high desulfation rate of 99.7%, and the sulfation time of lime from 30 min to 30 s with a sulfation rate of 98.6% with a net profit of 55.99 ¥/ton by cost accounting. Moreover, ten batches of continuous scale-up experiments demonstrate the stability of processes, the desulfation and sulfation rates are kept at 99.7% and 98.2%, which greatly reduces the emissions of waste desulfate liquor. This work provides a new universal strategy for a sustainable, low-cost, and clean desulfation method of waste resources to achieve technical and economic feasibility.

14.
ACS Appl Mater Interfaces ; 15(13): 16680-16691, 2023 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-36961955

RESUMO

The electrochemical nitrate reduction reaction (NO3RR) is considered as a promising strategy to degrade nitrate-containing wastewater and synthesize recyclable ammonia at atmospheric pressure and room temperature. In this work, the copper oxides-derived nano-polycrystalline Cu (NPC Cu) was integrated with Ti3+-self-doped TiO2 nanotube arrays (NTA) to fabricate the NPC Cu/H-TiO2 NTA. Ti3+-self-doped TiO2 NTAs and the NPC Cu facilitate electron transfer and mass transportation and create abundant active sites. The unique nanostructure in which Cu nano-polycrystals interlace with the TiO2 nanotube accelerates the electron transfer from the substrate to surface NPC Cu. The density functional theory calculations confirm that the built-in electric field between Cu and TiO2 improves the adsorption characteristic of the NPC Cu/H-TiO2 NTA, thereby converting the endothermic NO3- adsorption step into an exothermic process. Therefore, the high NO3- conversion of 98.97%, the Faradic efficiency of 95.59%, and the ammonia production yield of 0.81 mg cm-2 h-1 are achieved at -0.45 V vs reversible hydrogen electrode in 10 mM NaNO3 (140 mg L-1)-0.1 M Na2SO4. This well-designed NPC Cu/H-TiO2 NTA as an effective electrocatalyst for the 8e- NO3RR possesses promising potential in the applications of ammonia production.

15.
Dalton Trans ; 51(47): 18213-18223, 2022 Dec 06.
Artigo em Inglês | MEDLINE | ID: mdl-36399001

RESUMO

Metal-organic framework (MOF) derived porous carbon materials have been widely applied as active materials for supercapacitors due to their large specific surface area and ordered pore structure. This paper presents a facile and effective strategy to regulate the morphology of a zinc-based metal-organic framework (Zn-trimesic acid, Zn-BTC) by adjusting the ethanol content in a solvent, which can effectively change the pore structure of Zn-BTC derived porous carbon (PC). The optimal PC prepared in 50% ethanol displays a rodlike structure with a large specific surface area (SSA) of 1930 m2 g-1 and an average pore size of 2.9 nm. This material shows an excellent rate performance with 78.8% capacitance retention when the current density increases from 1 A g-1 to 100 A g-1 and outstanding electrochemical stability with only 2.2% decline of capacitance after 200 000 cycles at 50 A g-1. Moreover, the assembled symmetrical capacitor shows a high energy density of 16.09 W h kg-1 at 698 W kg-1 and 11.89 W h kg-1 at a high power density of 41.56 kW kg-1. This method would provide a new pathway for the preparation of carbon materials with an adjustable pore size for high-performance supercapacitors.

16.
Dalton Trans ; 51(6): 2538-2546, 2022 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-35075467

RESUMO

Metal organic frameworks (MOFs) and their derivatives have been widely used in electrochemistry due to their adjustable pore size and high specific surface area (SSA). Herein, a spindle-like hierarchical porous activated carbon (SPC) was synthesized through carbonizing the Al-BTEC precursor and then alkaline washing with NaOH. The fabricated SPC has a uniform shuttle-shaped structure, showing a large BET surface area of 1895 m2 g-1 and an average pore size of 2.4 nm. The SPC product displays a high specific capacitance (SC) of 337 F g-1 at 1 mV s-1 and 334 F g-1 at 1 A g-1. The retention of SC is about 95% after 100 000 cycles when the current density is 50 A g-1, indicating its excellent stability. Furthermore, the assembled symmetrical capacitor with a two-electrode system exhibits a high SC of 173 F g-1 at 1 A g-1 and an energy density of 15.3 W h kg-1 at a power density of 336 W kg-1. This work would provide a new pathway to design and synthesize carbon materials for supercapacitors with excellent properties in the future.

17.
ACS Appl Mater Interfaces ; 14(27): 30839-30846, 2022 Jul 13.
Artigo em Inglês | MEDLINE | ID: mdl-35763593

RESUMO

The quiescent electrolyte causes serious concentration polarization and dendrite problems during the charging and discharging of the battery, which restricts the development of metal secondary batteries and flow batteries. Herein, we report a new concept of ion motors, with which the directional driving and uniformity of the electrolyte are realized to eliminate the concentration polarization and dendritic phenomenon for secondary metal batteries and flow batteries without additional external energy. In this study, a dendrite-free secondary metal battery with ion motors is constructed to eliminate a considerable concentration polarization voltage by a tiny induced counter electromotive force generated by Lorentz force, significantly improving the output power and energy efficiency of the battery. An actual pump-free flow battery with an ion motor is also assembled, which overcomes the problems of low energy efficiency and the complex structure caused by the traditional flow battery requiring 1-2 pumps to drive the electrolyte. The efficiency of ion motors to drive the electrolyte is hundreds of times higher than that of the mechanical pump. Therefore, the ion motor provides a universal strategy for designing more pump-free flow batteries and metal secondary batteries without the risk of dendrites in the future.

18.
J Colloid Interface Sci ; 591: 9-19, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33588311

RESUMO

In this work, a hierarchically activated porous carbon (APC) was synthesized using fluorine-containing metal-organic framework via facile combined carbonization and KOH activation treatments. The influences of activation conditions on the surface structures and electrochemical performance of APC were systematically studied. Afterwards, the electrochemical responses of APC electrode were further assessed from the cyclic voltammetry and galvanostatic charge-discharge examinations by 6 M KOH electrolyte. The as-obtained APC electrode delivered the high specific capacitances of 540.8 and 280 F g-1 at 1 and 500 A g-1, correspondingly with superior capacitance retention of 94% after 250,000 cycles even at 100 A g-1, which is showing that its outstanding capacitance, remarkable rate capacity, and very-long cyclic life. Furthermore, the as-assembled APC-based symmetrical supercapacitor offers a superb energy density of 19 Wh kg-1 at 182 W kg-1, indicating its large-scale application. Thus, this work proposes a potential route to synthesize highly efficient porous carbon material for the future development of energy storage systems.

19.
ACS Appl Mater Interfaces ; 13(38): 45375-45384, 2021 Sep 29.
Artigo em Inglês | MEDLINE | ID: mdl-34529410

RESUMO

Herein, we propose a new concept of energy storage system composed of a nonpolarized electrode and a polarized electrode (PPE) with an impressive energy density. It offered nearly 4 times higher energy density than that of carbon-based supercapacitor. Among the suggested potential PPE system, we introduced an electrodeposited nanozinc on the copper foam as the nearly nonpolarized electrode and a Zn-2,5-dihydroxyterephthalic acid (DHTA) metal-organic framework (MOF)-derived activated porous carbon as a nearly polarized electrode in KOH-ZnO electrolyte to constitute the C|Zn PPE system prototype. The C|Zn system achieved an impressive energy density of 84.5 Wh kg-1 at 1000 W kg-1, 4 times higher than that of the C|C supercapacitor. It also shows a high capacitance retention rate of 94.5% at 10 A g-1 after 10 000 cycles. Therefore, the amazing results indicate that the PPE energy system integrates the advantages of supercapacitors and secondary batteries. It will be a promising and effective energy device for higher-performance electric vehicles.

20.
J Colloid Interface Sci ; 579: 347-356, 2020 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-32610207

RESUMO

Herein, we propose a new highly porous natural carbon material from renewable and inexpensive jujube fruits as a carbon source applied in supercapacitors. The combination of pre-carbonization and chemical activation approaches is employed to product hierarchical porous carbon from natural jujube fruits. The specific surface area of the prepared porous carbon is increased from 85.4 to 1135 m2 g-1 after the completion of NaOH activation at an optimized condition, which is beneficial to enhancing electrochemical performance of supercapacitors. A 3-electrode configuration was utilized to explore the electrochemical ability of porous carbon in 6 M KOH electrolyte. The acquired results demonstrate that porous carbon displays the specific capacitance of 587, 460 and 324 F g-1 at 0.1, 1 and 100 A g-1, respectively, which is confirmed by its admirable capacitance and rate behaviors. The porous carbon also shows a wonderful durability with a capacitance retention of 92.2% after 130,000 cycles at 50 A g-1. Moreover, the assembled symmetrical coin-like supercapacitors with wide potential window of 2.5 V in 1 M Et4NBF4/AN organic electrolyte offer a high energy density of 23.7 Wh kg-1 at 0.629 kW kg-1 with remaining 94% capacitance over 10,000 cycles at 30 A g-1, indicating its practical application prospect. As a result, the present study proves the natural jujube fruits is a promising sustainable carbon source for making more economical and efficient electrode material of high performance supercapacitors.


Assuntos
Carbono , Ziziphus , Capacitância Elétrica , Frutas , Porosidade
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