共查询到20条相似文献,搜索用时 31 毫秒
1.
The selection and preparation of an electrode material is the core of capacitive deionization. In order to obtain a material with a good deionization properties, we have designed an environmentally-friendly and simple way of preparing biochar. In this work, biochar was prepared by a thermal-deposition method and after chemical modification it was characterized with a scanning electron microscope (SEM), Fourier transform infrared spectrophotometer (FTIR), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The specific surface area of biochar modified by KOH is as high as 833.76 m2 g−1, but the specific surface area of the unmodified electrode material is only 126.43 m2 g−1. The electrochemical analysis (CV and EIS) of the biochar indicates that HC-800 has a lower charge transfer resistance and a higher specific capacitance, where the specific capacity of HC-800 reaches 120 F g−1. A CDI property analysis of HC-800 shows a better electrosorption capacity of 11.52 mg g−1 and better regeneration and cycling stability than CS-800. The desalination amount remains 87.23% after several cycles.Schematic illustration of the fabrication of chitin derived biochar and KOH-activated chitin derived biochar electrodes for capacitive deionization. 相似文献
2.
Membrane capacitive deionization (MCDI) is an effective process to remove salt ions from brackish water. In this work, a systematic investigation was carried out to study the effects of applied potential and salt concentration on salt adsorption capacity (SAC), charge efficiency (Λ) and energy consumption in an MCDI system using Luffa biowaste derived carbon as electrodes. We studied the comparative MCDI performance of Luffa derived carbon as electrodes before and after activation. Furthermore, the desalination capacities of the electrodes were quantified by batch-mode experiments in a 2500 mg L−1 NaCl solution at 0.8–1.2 V. Activated Luffa carbon showed a high SAC of 38 mg g−1 at 1.2 V in a 2500 mg L−1 NaCl solution with a low energy consumption of 132 kJ mol−1 salt as compared to non-activated samples (22 mg g−1, 143 kJ mol−1). The adsorption mechanisms were investigated using kinetic models and isotherms under various applied potentials. Consequently, the excellent SAC of activated Luffa carbon can be attributed to the presence of micro/mesoporous network structure formed due to the activation process for the propagation of the salt ions.Membrane capacitive deionization (MCDI) is an effective process to remove salt ions from brackish water. 相似文献
3.
Technologies for the effective and energy efficient removal of salt from saline media for advanced water remediation are in high demand. Capacitive deionization using carbon electrodes is limited to highly diluted salt water. Our work demonstrates the high desalination performance of the silver/silver chloride conversion reaction by a chloride ion rocking-chair desalination mechanism. Silver nanoparticles are used as positive electrodes while their chlorination into AgCl particles produces the negative electrode in such a combination that enables a very low cell voltage of only Δ200 mV. We used a chloride-ion desalination cell with two flow channels separated by a polymeric cation exchange membrane. The optimized electrode paring between Ag and AgCl achieves a low energy consumption of 2.5 kT per ion when performing treatment with highly saline feed (600 mM NaCl). The cell affords a stable desalination capacity of 115 mg g−1 at a charge efficiency of 98%. This performance aligns with a charge capacity of 110 mA h g−1.The silver/silver chloride conversion reaction allows for a high desalination capacity of saline media with high molar strength. 相似文献
4.
Yan Liu Yun Tian Jianda Xu Changfu Wang Yun Wang Dingzhong Yuan Jia Wei Chew 《RSC advances》2023,13(10):6518
Due to its unique advantages such as flexible planar structure, ultrahigh specific surface area, superior electrical conductivity and electrical double-layer capacitance in theory, graphene has unparalleled virtues compared with other carbon materials. This review summarizes the recent research progress of various graphene-based electrodes on ion electrosorption fields, especially for water desalination utilizing capacitive deionization (CDI) technology. We present the latest advances of graphene-based electrodes, such as 3D graphene, graphene/metal oxide (MO) composites, graphene/carbon composites, heteroatom-doped graphene and graphene/polymer composites. Furthermore, a brief outlook on the challenges and future possible developments in the electrosorption area are also addressed for researchers to design graphene-based electrodes towards practical application.Graphene-based materials used in electrosorption: (1) 3D graphene; (2) graphene/MO; (3) graphene/carbon composites; (4) heteroatom-doped graphene; (5) graphene/polymer-based. 相似文献
5.
Properties of amorphous iron phosphate in pseudocapacitive sodium ion removal for water desalination
Capacitive deionization (CDI) is an energy saving and environmentally friendly technology for water desalination. However, classical CDI is challenged by a low salt removal capacity. To improve the desalination capacity, electrode materials utilizing the battery mechanism for salt ion removal have emerged as a new direction more recently. In this work, we report a study of amorphous iron phosphate (FePO4) as a promising electrode material for pseudocapacitive sodium ion removal. Sodium ions can be effectively, reversibly intercalated and de-intercalated upon its electrochemical reduction and oxidation, with an excellent sodium ion capacity under half-cell testing conditions. By assembling a hybrid CDI (HCDI) system utilizing the FePO4 electrode for pseudocapacitive sodium ion removal and active carbon electrode for capacitive chloride ion removal, the cell exhibited a high salt removal capacity and good reversibility and durability, which was attributed to the advantageous features of amorphous FePO4. The HCDI system achieved a high deionization capacity (82 mg g−1) in 10 mM NaCl, a fast deionization rate (0.046 mg g−1 s−1), and good stability and cyclability.Amorphous iron phosphate (FePO4) exhibits excellent capacity, reversibility and stability in pseudocapacitive sodium ion removal for water desalination. 相似文献
6.
Adam R. Wood Raghav Garg Tzahi Cohen-Karni Alan J. Russell Philip LeDuc 《RSC advances》2021,11(16):9628
Each year approximately 1.3 billion tons of food is either wasted or lost. One of the most wasted foods in the world is bread. The ability to reuse wasted food in another area of need, such as water scarcity, would provide a tremendous sustainable outcome. To address water scarcity, many areas of the world are now implementing desalination. One desalination technology that could benefit from food waste reuse is capacitive deionization (CDI). CDI has emerged as a powerful desalination technology that essentially only requires a pair of electrodes and a low-voltage power supply. Developing freestanding carbon electrodes from food waste could lower the overall cost of CDI systems and the environmental and economic impact from food waste. We created freestanding CDI electrodes from bread. The electrodes possessed a hierarchical pore structure that enabled both high salt adsorption capacity and one of the highest reported values for hydraulic permeability to date in a flow-through CDI system. We also developed a sustainable technique for electrode fabrication that does not require the use of common laboratory equipment and could be deployed in decentralized locations and developing countries with low-financial resources.Sustainable approach to fabrication of capacitive desalination electrodes using food waste (bread). 相似文献
7.
8.
Hybrid ion capacitors (HICs) based on insertion reactions have attracted considerable attention due to their energy density being much higher than that of the electrical double-layer capacitors (EDLCs). However, the development of hybrid ion capacitors with high energy density at high power density is a big challenge due to the mismatch of charge storage capacities and electrode kinetics between the battery-type anode and capacitor-type cathode. In this work, N and O dual doped carbon nanofibers (N,O-CNFs) were combined with carbon nanotubes (CNTs) to compose a complex carbon anode. N,O dual doping effectively tuned the functional group and surface activity of the CNFs while the integration of CNTs increased the extent of graphitization and electrical conductivity. The carbon cathode with high specific surface area and high capacity was obtained by the activation of CNFs (A-CNFs). Finally, a hybrid sodium ion capacitor was constructed by the double carbon electrode, which showed a superior electrochemical capacitive performance. The as-assembled HIC device delivers a maximum energy density of 59.2 W h kg−1 at a power density of 275 W kg−1, with a high energy density of 38.7 W h kg−1 at a power density of 5500 W kg−1.A hybrid sodium ion capacitor is constructed by the double carbon electrode, whose precursors are both from nanofibers of bacterial cellulose, showing a superior electrochemical capacitive performance. 相似文献
9.
Capacitive deionization (CDI) is a novel low-energy green desalination technology that has attracted much attention in recent years, especially for the desalination of low salinity water. One of the key issues in CDI is the electrode materials, and many efforts have been devoted to developing materials with high specific surface areas, appropriate pore distributions, and good electronic conductivity, in order to obtain a high salt adsorption capacity. In this study, chitosan was selected as a precursor for the preparation of high-performance chitosan-based activated carbon (CTS-AC) for use in CDI electrodes via pyrolysis and KOH activation. The results show that CTS-AC800 (activated at 800 °C) has the largest BET specific surface area (2727 m2 g−1), and exhibits an appropriate pore size distribution (<10 nm), nitrogen doping (2.0%) and good electronic conductivity (2.09 S cm−1). The CDI performance results show that the CTS-AC800 electrode has a saturated salt adsorption capacity of 14.12 mg g−1 in a 500 mg L−1 NaCl solution and retains 95% capacity after 150 adsorption–desorption cycles. Thus, chitosan is a promising, sustainable precursor for CDI electrode materials.Chitosan was selected as a carbonaceous precursor to prepare high-performance chitosan-based activated carbon (CTS-AC) for CDI electrode. 相似文献
10.
Adam R. Wood Raghav Garg Kyle Justus Tzahi Cohen-Karni Philip LeDuc Alan J. Russell 《RSC advances》2019,9(9):4735
Through the benefit of billions of years of evolution, biology has developed tremendous strategies on how to co-exist in high salinity and water scarce environments. Biologically-inspired abiotic systems are becoming a central pillar in how we respond to critical grand challenges that accompany exponential population growth, uncontrolled climate change and the harsh reality that 96.5% of the water on the planet is saltwater. One fascinating biologic adaptation to saltwater is the growth of mangrove trees in brackish swamps and along the coasts. Through a process of salt exclusion, the mangrove maintains a near freshwater flow from roots to leaves to survive. One abiotic approach to water desalination is capacitive deionization, which aims to desalinate low-salinity water sources at energy costs below current technologies, such as reverse osmosis and thermal distillation. In this work, we use one-step carbonization of a plant with developed aerenchyma tissue to enable highly-permeable, freestanding flow-through capacitive deionization electrodes. We show that carbonized aerenchyma from red mangrove roots reduces the resistance to water flow through electrodes by 65-fold relative to carbonized common woody biomass. We then demonstrate the practical use of the intact carbonized red mangrove roots as electrodes in a flow-through capacitive deionization system. These findings have implications in a range of fields including water desalination, bioinspired materials, and plant functionality.Biological adaptation in mangrove root enables freestanding carbonized architecture to be used as a highly permeable flow-through capacitive deionization electrode. 相似文献
11.
Ehsan Delfani Alireza Khodabakhshi Sajjad Habibzadeh Leila Naji Mohammad Reza Ganjali 《RSC advances》2021,12(2):907
Capacitive deionization (CDI), as an emerging eco-friendly electrochemical brackish water deionization technology, has widely benefited from carbon/metal oxide composite electrodes. However, this technique still requires further development of the electrode materials to tackle the ion removal capacity/rate issues. In the present work, we introduce a novel active carbon (AC)/Co3O4–Sb2O3–SnO2 active material for hybrid electrode capacitive deionization (HECDI) systems. The structure and morphology of the developed electrodes were determined using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and Brunauer–Emmett–Teller (BET)/Barrett–Joyner–Halenda (BJH) techniques, as well as Fourier-transform infrared (FT-IR) spectroscopy. The electrochemical properties were also investigated by cyclic voltammetry (CV) and impedance spectroscopy (EIS). The CDI active materials AC/Co3O4 and AC/Co3O4–Sb2O3–SnO2 showed a high specific capacity of 96 and 124 F g−1 at the scan rate of 10 mV s−1, respectively. In addition, the newly-developed electrode AC/Co3O4–Sb2O3–SnO2 showed high capacity retention of 97.2% after 2000 cycles at 100 mV s−1. Moreover, the electrode displayed excellent CDI performance with an ion removal capacity of 52 mg g−1 at the applied voltage of 1.6 V and in a solution of potable water with initial electrical conductivity of 950 μs cm−1. The electrode displayed a high ion removal rate of 7.1 mg g−1 min−1 with an excellent desalination–regeneration capability while retaining about 99.5% of its ion removal capacity even after 100 CDI cycles.Capacitive deionization (CDI), as an emerging eco-friendly electrochemical brackish water deionization technology, has widely benefited from carbon/metal oxide composite electrodes. 相似文献
12.
Carbon materials are often used as both positive and negative electrodes (bipolar electrode materials) in energy storage devices, which significantly reduces the preparation complexity of the electrode. Herein, oxygen-modified carbon nanotubes mounted on carbon cloth (CCC) present a high areal capacitance as both positive and negative electrodes in a safe neutral electrolyte. The introduction of oxygen functional groups facilitates the formation of many electrochemical active sites and defects conducive to ion diffusion. When carbon materials are utilized as negative electrodes, the charge storage characteristics are mainly dependent on the adsorption and desorption of the ions (corresponding to the electric double layer capacitance). Whereas, when utilized as positive electrodes, the charge storage characteristics come from the intercalation and de-intercalation of the electrolyte ions in the multi-defect carbon material. The maximum areal capacitance measured at the positive electrode and negative electrode was 336 mF cm−2 and 158 mF cm−2, respectively. The measured areal capacitance of the assembled symmetrical supercapacitors was 93.6 mF cm−2, and the areal energy density reached 33 μW h cm−2 at a power density of 793 μW cm−2. It is believed that the efficient preparation method and electrochemical mechanism elucidated in this work can guide the practical applications of carbon cloth in supercapacitors.Carbon materials with effective oxygen functional groups as positive and negative electrodes and their special energy storage mechanism. 相似文献
13.
X. F. Zhang B. Wang J. Yu X.
N. Wu Y. H. Zang H. C. Gao P. C. Su S. Q. Hao 《RSC advances》2018,8(3):1159
In this study, porous carbon (3DHPC) with a 3D honeycomb-like structure was synthesized from waste biomass corncob via hydrothermal carbonization coupled with KOH activation and investigated as a capacitive deionization (CDI) electrode material. The obtained 3DHPC possesses a hierarchal macroporous and mesoporous structure, and a large accessible specific surface area (952 m2 g−1). Electrochemical tests showed that the 3DHPC electrode exhibited a specific capacitance of 452 F g−1 and good electric conductivity. Moreover, the feasibility of electrosorptive removal of chromium(vi) from an aqueous solution using the 3DHPC electrode was demonstrated. When 1.0 V was applied to a solution containing 30 mg L−1 chromium(vi), the 3DHPC electrode exhibited a higher removal efficiency of 91.58% compared with that in the open circuit condition. This enhanced adsorption results from the improved affinity between chromium(vi) and the electrode under electrochemical assistance involving a non-faradic process. Consequently, the 3DHPC electrode with typical double-layer capacitor behavior is demonstrated to be a favorable electrode material for capacitive deionization.A porous carbon electrode with a 3D honeycomb-like structure demonstrates a high removal efficiency for the removal of chromium(vi) from water. 相似文献
14.
Graphene is a promising electrode material for supercapacitors due to its superior physical and chemical properties, but the influence of its oxygen functional groups on capacitive performance still remains somewhat uncertain. In this work, graphene sheets with different oxygen content have been prepared through thermal reduction in argon. Furthermore, oxidation and pore-forming treatment of graphene annealed at 800 °C are also performed to explore the important effect of oxygen functional groups. The effects of disorder degree, surface area and oxygen functional groups on the specific capacitance were explored systematically. The content and species of oxygen functional groups are found to be significant factors influencing the electrochemical supercapacitor performance of graphene electrodes. The specific capacitances of graphene annealed at 200, 400 and 800 °C are 201, 153 and 34 F g−1, respectively. However, the specific capacitance of graphene reduced at 800 °C can be increased to 137 F g−1 after nitric acid oxidation treatment, and is only 39 F g−1 after pore forming on graphene surface, demonstrating that the oxygen functional groups can improve the capacitive performances of graphene electrochemical supercapacitors.The content and species of oxygen functional groups are significant factors influencing the electrochemical supercapacitor performance of graphene electrodes. 相似文献
15.
We probed electrochemical ion storage in single-walled carbon nanotubes (SWCNTs) of different diameters in two different organic electrolytes using electrochemical quartz crystal microbalance (EQCM) tracking. The measurements showed that charge storage probed by cyclic voltammetry did not deteriorate when steric effects seemed to hinder the accessibility of counter-ions into SWCNTs, and instead proceeded predominantly by co-ion desorption, as was shown by the decrease in the electrode mass probed by EQCM. The dominant mechanism correlated with the SWCNT diameter/ion size ratio; counter-ion adsorption dominated in the whole potential range when the diameter of SWCNTs was comparable to the size of the largest ion, whereas for larger diameters the charge increase coincided with a decrease in the electrode mass, indicating the dominance of co-ion desorption. The dominance of co-ion desorption was not observed in activated carbon, nor was it previously reported for other carbon materials, and is likely switched on because the carrier density of SWCNT increases with applied potential, and maintains the electrode capacity by co-ion desorption to overcome the steric hindrances to counter-ion adsorption.The increase in charge carrier density in SWCNTs with applied potential overcomes steric hindrance to counter-ion adsorption by switching the dominant charge storage mechanism to co-ion desorption. 相似文献
16.
A hierarchical structure consisting of Ni–Co hydroxide nanosheets (NCHN) electrodeposited on vertically-oriented graphene nanosheets (GN) on carbon cloth (CC) was fabricated for high-performance pseudocapacitive electrodes. NCHN was uniformly distributed on GN, forming a sheet-on-sheet hierarchical structure. Such NCHN/GN/CC hybrid electrodes exhibit high capacitance and ultrahigh electrochemical-stability that structure and electrochemical properties of hybrid electrodes are not affected by the cyclic low-rate scanning (at 5 mV s−1 even over 1000 cycles). GN vertically grown on CC is used as nano-bridge between NCHN active materials and CC current collector, which effectively facilitates ion/charge transfer between the electrolyte and electrode, consequently leading to the ultrahigh electrochemical-stability of hybrid electrodes. To assess functional behavior, two-terminal flexible asymmetric supercapacitor devices with NCHN/GN/CC as positive electrode and GN/CC as negative electrode were assembled and electrochemically treated to demonstrate the ultrahigh electrochemical stability.Vertically-oriented graphene nanosheet as nano-bridge for pseudocapacitive electrode facilitates the ion/charge transfer efficiency, leading to ultrahigh electrochemical stability. 相似文献
17.
A high-performance Ni(OH)2 nanoarray on graphene (RGO)@carbon fabric nanocomposites with hierarchical nanostructures were facilely synthesized, which involves (i) coating of graphene on a carbon fabric; and (ii) in situ growth of Ni(OH)2 nanoarray on the graphene surface. It was found that Ni(OH)2 nanoplates grew evenly on the surface of graphene without stacking. This unique structure of the electrode material favors a higher electrochemical active site, endowing the enhancing capacity performance. The morphology and microstructure of the as-prepared composites were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and scanning electron microscopy (SEM) techniques. Capacitive properties of the as-synthesized electrodes were studied via cyclic voltammetry, charge/discharge, and electrochemical impedance spectroscopy in a three-electrode experimental setup. Taking advantage of the unique structure of Ni(OH)2/RGO@carbon fabric nanocomposites, this material as dual-functional electrodes shows decent performance for both supercapacitors and capacitive desalination (CDI). The specific capacitance was calculated to be 1325 F g−1 at 1 A g−1; moreover, this material shows a high rate capability, whereby the capacitance can be maintained at 612 F g−1 even at 10 A g−1. Besides, its performance as potential CDI electrodes was explored. Such high-performance Ni(OH)2/RGO@carbon fabric hierarchical nanostructures can offer great promise in large-scale energy storage device applications.This work reported the synthesis of dual-functional electrode Ni(OH)2 nanoarrays on RGO@carbon fabric nanocomposites with hierarchical nanostructures. The electrode showed decent performance on both supercapacitor and CDI. 相似文献
18.
To overcome the environmental challenges caused by utilization of fossil fuel based energy technologies and to utilize the full potential of renewable energy sources such as solar, wind and tidal, high power and high energy density containing large scale electrochemical energy storage devices are a matter of concern and a need of the hour. Pseudocapacitors with accessibility to multiple oxidation states for redox charge transfer can achieve a higher degree of energy storage density compared to electric double layer capacitors (EDLC) and the hybrid supercapacitor is one of the prominent electrochemical capacitors that can resolve the low energy density issues associated with EDLCs. Due to its open pore framework structure with superior structural stability and accessibility of Co2+/3+/4 redox states, porous anhydrous CoC2O4 nanorods are envisaged here as a potential energy storage electrode in a pseudo-capacitive mode. Superior specific capacitance equivalent to 2116 F g−1 at 1 A g−1 in the potential window of 0.3 V was observed for anhydrous CoC2O4 nanorods in aqueous 2 M KOH electrolyte. A predominant pseudo-capacitive mechanism seems to be operative behind the high charge storage at electrodes as intercalative (Inner) and surface (outer) charge storage contributions were found to be 75% and 25% respectively. Further, in full cell asymmetric supercapacitor (ASC) mode in which porous anhydrous CoC2O4 nanorods were used as positive electrodes and activated carbon (AC) was utilised as negative electrodes within an operating potential window of 1.3 V, a highest specific energy of W h kg−1 and specific power of ∼647 W kg−1 at 0.5 A g−1 current density were obtained with superior cycling stability. High cycling stability coupled with superior electrochemical storage properties make anhydrous CoC2O4 nanorods potential pseudo-capacitive electrodes for large scale energy storage applications.With active participation of Co2+/3+ redox couples in an oxalate framework, Anhydrous CoC2O4 nanorods display a capacitance equivalent to 2116 F g−1 at 1 A g−1 current rate in the potential window of 0.3 V in aqueous 2 M KOH electrolyte. 相似文献
19.
Nitrogen doped carbon nanoparticles on highly porous carbon nanofiber electrodes were successfully synthesized via combining centrifugal spinning, chemical polymerization of pyrrole and a two-step heat treatment. Nanoparticle-on-nanofiber morphology with highly porous carbon nanotube like channels were observed from SEM and TEM images. Nitrogen doped carbon nanoparticles on highly porous carbon nanofiber (N-PCNF) electrodes exhibited excellent cycling and C-rate performance with a high reversible capacity of around 280 mA h g−1 in sodium ion batteries. Moreover, at 1000 mA g−1, a high reversible capacity of 172 mA h g−1 was observed after 300 cycles. The superior electrochemical properties were attributed to a highly porous structure with enlarged d-spacings, enriched defects and active sites due to nitrogen doping. The electrochemical results prove that N-PCNF electrodes are promising electrode materials for high performance sodium ion batteries.Nitrogen doped carbon nanoparticles on highly porous carbon nanofiber electrodes were successfully synthesized via combining centrifugal spinning, chemical polymerization of pyrrole and a two-step heat treatment. 相似文献
20.
Chong Wang Changzhen Zhan Xiaolong Ren Ruitao Lv Wanci Shen Feiyu Kang Zheng-Hong Huang 《RSC advances》2019,9(72):42316
Lithium ion capacitors (LICs), bridging the advantages of batteries and electrochemical capacitors, are regarded as one of the most promising energy storage devices. Nevertheless, it is always limited by the anodes that accompany with low capacity and poor rate performance. Here, we develop a versatile and scalable method including ball-milling and pyrolysis to synthesize exfoliated MoS2 supported by N-doped carbon matrix derived from chitosan, which is encapsulated by pitch-derived carbon shells (MoS2/CP). Because the carbon matrix with high nitrogen content can improve the electron conductivity, the robust carbon shells can suppress the volume expansion during cycles, and the sufficient exfoliation of lamellar MoS2 can reduce the ions transfer paths, the MoS2/CP electrode delivers high specific capacity (530 mA h g−1 at 100 mA g−1), remarkable rate capability (230 mA h g−1 at 10 A g−1) and superior cycle performance (73% retention after 250 cycles). Thereby, the LICs, composed of MoS2/CP as the anode and commercial activated carbon (21 KS) as the cathode, exhibit high power density of 35.81 kW kg−1 at 19.86 W h kg−1 and high energy density of 87.74 W h kg−1 at 0.253 kW kg−1.MoS2/carbon composites prepared by ball-milling and pyrolysis for the high-rate anode of lithium ion capacitors. 相似文献