Cobalt Carbonate Research Articles

Bi doping induces the quantum dots to improve the supercapacitor performance of cobalt carbonate hydroxide hydrate

Cobalt carbonate hydroxide has been widely used in supercapacitor electrodes because of its excellent theoretical electrochemical properties and easy synthesis. However, in actual synthesis, its excellent electrochemical properties are often weakened due to its oxide-like properties, which restricts its further development. Herein, the Bi heteroatoms are introduced into the Co(CO3)0.5(OH)·0.11H2O, which not only modifies the microstructure, but also induces the formation of quantum dots, thus improving the performance of supercapacitors. By regulating the doping amount of Bi, the optimized Co/Bi-3:1 exhibits a specific capacitance of 680 F g−1 at 1 A g−1, which is 5.74 times than the pristine Co(CO3)0.5(OH)·0.11H2O. Furthermore, the assembled Co/Bi-3:1//activated carbon soft-pack asymmetric supercapacitor has a relatively superior power density (10547.58 W kg−1, relative to 14.06 Wh kg−1 energy density) and energy density (17.83 Wh kg−1, relative to 2146.76 W kg−1 power density). The present study demonstrates that Bi doping not only facilitates the formation of quantum dots and enhances electron conduction ability, but also regulates the microscopic morphology, thereby enhancing the electrochemical energy storage capacity of cobalt carbonate hydroxide hydrate electrode materials.

Biocompatibility, antimicrobial efficacy, and therapeutic potential of cobalt carbonate nanoparticles in wound healing, sex hormones, and metabolic regulation in diabetic albino mice

Nanotechnology enables the manipulation of materials at the nanoscale, offering innovative solutions in various fields. Nanoparticles, with their small size and unique properties, have significant applications in the biomedical filed. The current study was designed to assess the biological applications of self-synthesized cobalt carbonate (CoCO3) nanoparticles. The crystalline structure and chemical composition of the CoCO3-NPs were confirmed by SEM, XRD, and FTIR techniques. We observed the 16.58 nm size of novelly synthesized CoCO3 NPS. The scanning electron microscope study confirmed a uniform cubic spinel structure. The biocompatibility and antimicrobial activity were checked in an invitro setup. We exposed albino mice to these synthesized NPs to study wound healing and metabolic effects. The results of biocompatibility analysis indicated hemolytic activity in a dose-dependent way, which showed no cytotoxic effect except at a higher concentration. Furthermore, the results showed enhanced wound healing processes in CoCO3-NP-treated albino mice as compared to the control group. CoCO3-NPs have considerable effect on the thyroid hormone and insulin levels in albino mice. The levels of T3, T4, and insulin were increased in a dose-dependent manner. Interactions between CoCO3-NPs and thyroxine and insulin were confirmed through molecular docking. We confirmed the antimicrobial efficiency of the nanoparticles using MIC values and zones of inhibition against Staphylococcus haemolyticus and Staphylococcus aureus. Despite their concentration-dependent biocompatibility concerns, the results are promising, as CoCO3-NPs hold potential for use in medical practice, particularly in advanced wound management and microbe inhibition.

Bioinspired Composite Fabrics with Nanoneedle Structures for High Wicking-Evaporation performance

Achieving ultrafast antigravity water transport and evaporation in high-performance moisture-wicking fabrics remains a significant challenge in textile engineering. In this study, we introduce two novel asymmetric composite fabrics, NN-TS/PET/BS and NS-TS/PET/BS, developed through a straightforward one-step method. These fabrics incorporate different hydrophilic nanostructures—nanoneedles (NN) and nanosheets (NS) of cobalt carbonate—to enhance wicking-evaporation capabilities. The NN-TS/PET/BS fabric exhibited superior unidirectional water transport and evaporation performance, achieving a one-way transport value (R) of up to 330%, an outstanding overall moisture management capacity (OMMC) of 0.87, and a rapid water evaporation rate of 0.5 g h⁻¹, which is 2 and 2.3 times higher than that of NS-TS/PET/BS and Coolmax, respectively. Detailed analyses revealed that the curvature gradients in the nanoneedles significantly enhanced the wetting and evaporation stages, facilitating efficient antigravity water transport. Wear studies confirmed that the NN-TS/PET/BS fabric could swiftly remove sweat from the skin surface, enhancing comfort and performance. These findings offer new perspectives for developing high-performance unidirectional water transport fabrics with broad application potential, including smart textiles, fog harvesting, and wound dressings.

Life Cycle Assessment of Cobalt Catalyst Production and Recycling

Catalysts with an active phase of cobalt are crucial for Fischer–Tropsch synthesis (FTS), yet the environmental impacts of the catalyst production and the recycling of the spent catalyst remain largely unknown. The goal of this study was to evaluate the impacts of both catalyst production as well as the recycling of spent catalyst as cobalt hydroxide, cobalt sulfate, or cobalt carbonate. Life cycle assessment (LCA) was used to quantify the environmental impacts of the studied processes. The life cycle inventory (LCI) was gathered based on the mass and energy balances of process simulations built on information available in the literature. The results show that compared to primary production of equivalent products, all studied recycling processes for spent catalyst decrease the environmental impacts by more than 50% in all investigated impact categories. For example, the global warming potential (GWP) of cobalt recovery from spent FTS catalyst as cobalt sulfate was 1.7 kg CO2-eq./kg CoSO4whereas the corresponding GWP for primary production was 4 kg CO2-eq./kg CoSO4. The process hotspots of recycling were found to be the production of the chemicals consumed, particularly sodium hydroxide and sulfuric acid, which together contributed between 64 and 95% of the total environmental impacts. LCAs on FTS have included the consumption of cobalt catalyst in the LCI using various approximations. The impacts calculated for the production of cobalt catalyst in this study were found to be markedly higher. The largest contributors included the production of materials for the precursor and support, as well as NOx emissions and consumption of nitric acid.Graphical

Engineering Water-Lotus-like Iridium-Cobalt Carbonate Hydroxides on Plasma-Treated Carbon Fibers for Enhanced Electrocatalytic Oxygen Evolution.

The sluggish kinetics of the oxygen evolution reaction (OER) in alkaline water electrolysis remains a significant challenge for developing high-efficiency electrocatalytic systems. In this study, we present a three-dimensional, micrometer-sized iridium oxide (IrO2)-decorated cobalt carbonate hydroxide (IrO2-P-CoCH) electrocatalyst, which is engineered in situ on a carbon cloth (CC) substrate pretreated with atmospheric-pressure dielectric barrier discharge (DBD) plasma (PCC). The electrocatalyst features petal-like structures composed of nanosized rods, providing abundant reactive areas and sites, including the oxygen vacancy caused by the air-DBD plasma. As a result, the IrO2-P-CoCH/PCC electrocatalyst demonstrates an outstanding OER performance, with overpotentials of only 190 and 300 mV required to achieve current densities of 10 mA cm-2 (j10) and 300 mA cm-2 (j300), respectively, along with a low Tafel slope of 48.1 mV dec-1 in 1.0 M KOH. Remarkably, benefiting from rich active sites exposed on the IrO2-P-CoCH (Ir) heterostructure, the synergistic effect between IrO2 and CoCH enhances the charge delivery rates, and the IrO2-P-CoCH/PCC exhibits a superior electrocatalytic activity at a high current density (300 mV/j300) compared to the commercial benchmarked RuO2/PCC (470 mV/j300). Furthermore, the IrO2-P-CoCH/PCC electrocatalyst shows exceptional OER stability, with a mere 1.3% decrease with a current density of j10 for 100 h testing, surpassing most OER catalysts based on CC substrates. This work introduces a novel approach for designing high-performance OER electrocatalysts on flexible electrode substrates.

Molybdenum and Vanadium-Codoped Cobalt Carbonate Nanosheets Deposited on Nickel Foam as a High-Efficient Bifunctional Catalyst for Overall Alkaline Water Splitting.

To address issues of global energy sustainability, it is essential to develop highly efficient bifunctional transition metal-based electrocatalysts to accelerate the kinetics of both the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER). Herein, the heterogeneous molybdenum and vanadium codoped cobalt carbonate nanosheets loaded on nickel foam (VMoCoCOx@NF) are fabricated by facile hydrothermal deposition. Firstly, the mole ratio of V/Mo/Co in the composite is optimized by response surface methodology (RSM). When the optimized composite serves as a bifunctional catalyst, the water-splitting current density achieves 10 mA cm-2 and 100 mA cm-2 at cell voltages of 1.54 V and 1.61 V in a 1.0 M KOH electrolyte with robust stability. Furthermore, characterization is carried out using field emission scanning electron microscopy-energy dispersive spectroscopy (FESEM-EDS), high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). Density functional theory (DFT) calculations reveal that the fabricated VMoCoCOx@NF catalyst synergistically decreases the Gibbs free energy of hydrogen and oxygen-containing intermediates, thus accelerating OER/HER catalytic kinetics. Benefiting from the concerted advantages of porous NF substrates and clustered VMoCoCOx nanosheets, the fabricated catalyst exhibits superior electrocatalytic performance. This work presents a novel approach to developing transition metal catalysts for overall water splitting.

Mechanosynthesis of pseudocapacitive MnCO3 and CoCO3 electroactive materials

Transition metals are known for their enormous potential as electrode materials for supercapacitor applications, however anhydrous carbonate minerals, namely Mn-carbonate, and Co-carbonate, are less explored and exhibit competitive energy storage performance compared to oxide and hydroxide forms. For the first time, MnCO3 (Rhodochrosite), CoCO3 (Spherocobaltite) and MnCo mixture (Mn1-xCoxCO3) were synthesized via mechanochemistry by a one-pot approach and used to prepare pseudocapacitive electrode materials for electrochemical energy storage. In this work, these materials were tested in alkaline electrolyte, and the morphological and structural features of the materials were examined using SEM (Scanning Electron Microscope), Transmission Electron Microscopy (TEM) and X-ray Diffraction (XRD). The surface composition was studied by X-ray photoelectron spectroscopy (XPS). After milling, the microstructures showed an increase in dislocations and microstrains in their crystal lattices which influenced the electrochemical performance. The crystallinity of the carbonate materials was also affected by grinding. In 1 M KOH electrolyte, milled MnCO3 evidenced the highest specific capacitance (354.3 F/g at 1.0 A/g), while milled CoCO3, revealed impressive capacitance retention of 94.8 % after 20000 continuous charge–discharge cycles at 10 A/g. Interestingly, the composite (Mn-Co)CO3 evidenced superior rate capability (58.8 %) and enhanced capacitance retention under cycling compared to the individual cobalt and manganese carbonates. The results evidence the excellent electrochemical behavior of Mn and Co carbonates prepared by a simple, low-cost, and green route and prove their potential as electroactive electrode materials for electrochemical energy storage applications, particularly pseudocapacitors.

Self-supporting NiCo carbonate hydroxyl nanosheet for ultra-high energy density and stable supercapacitors

Carbonates and hydroxides are common hydrophilic oxygen-containing functional groups, which are conducive to complete contact with aqueous solution, thus expanding the active area and improving the electrochemical performance of materials. Here, we propose a new synthesis method using nickel foam as the sole nickel source to prepare dense and ultra-thin self-supporting cobalt carbonate hydroxide nanosheets, which are rich in many hydrophilic functional groups. This method goes beyond the traditional layered double hydroxides by combining CO32− and OH− groups, thus promoting more efficient interaction with the electrolyte and creating a larger contact area between the electrode and the electrolyte. When applied in an asymmetric supercapacitor, this material attains an ultrahigh energy density of 9.69 mWh cm−3 at a power density of 43.29 mW cm−3 (even at elevated power densities, e.g., 4.14 mWh cm−3 at 425.52 mW cm−3), with 90 % capacity retention over 5000 cycles at 100 mA cm−2.

Dodecyl sulfate ions co-intercalated nickel cobalt carbonate hydroxide with multiwall carbon nanotube: An advanced catalyst for the electrochemical detection of nilutamide

Nilutamide (NLD) serves as a crucial anti-androgen drug for prostate cancer treatment; however, its elevated presence poses ecological risks. Monitoring NLD in environmental and biological samples is imperative. Layered double hydroxide (LDH) stands out as an intriguing electrocatalyst material, and this study focuses on enhancing its properties by hydrothermally preparing a hydrophobic LDH through co-intercalation of dodecyl sulfate anion in nickel cobalt carbonate hydroxide (NCCH). The catalytic performance is further improved by incorporating multiwall carbon nanotubes (MWCNT) to achieve precision and sensitivity in the electrochemical detection of NLD. The resulting NCCH/MWCNT-based electrochemical sensor demonstrates excellent structural, functional, and morphological characteristics verified by various spectroscopic techniques. Electrochemical analyses reveal impressive results, including a low detection limit (0.001 μM), quantification limit (0.0036 μM), two linear ranges (0.01–59.19 μM and 59.19–537.19 μM), and high sensitivity (3.957 μA μM−1cm−2). The practical utility is confirmed through successful monitoring of NLD in environmental and biological samples with satisfactory recoveries. In conclusion, NCCH/MWCNT emerges as a superior electrode material for the selective detection of NLD, showcasing its potential in environmental monitoring and clinical applications.

Constructing Ru single-atomic sites through potential-induced self-reconstruction to accelerate electrocatalytic nitrate reduction for ammonia production

Conversion of NO3−-to-NH3 via the electrocatalytic nitrate reduction reaction (NO3-RR) is an emerging strategy for ammonia production and storage of “green hydrogen”, but is limited by the dissatisfactory activity and selectivity. In this study, we discovered that cobalt carbonate hydroxide (Co2(OH)2CO3) underwent a potential-induced self-reconstruction to cobalt hydroxide (Co(OH)2) during NO3-RR. The incorporation of Ru into Co2(OH)2CO3 expedited the aforementioned self-reconstruction process and resulted in the formation of Ru single-atomic sites (Ru SASs) anchored on Co(OH)2 nanosheets. This structure is reported as a highly efficient electrocatalyst for NO3−-to-NH3 conversion and exhibits exceptional electrochemical performance in zinc-NO3− batteries. Theoretical analysis revealed that the conversion of NO3−-to-NH3 occurred on Ru SASs through an N-end pathway with *NO as a characteristic intermediate. Furthermore, Ru SASs facilitated the thermodynamic-determining step of *NH2-to-*NH3, thus promoting the overall NO3−-to-NH3 conversion process.

Two-dimensional flake Co/Co2N0.67 modified by molybdenum oxides achieves enhancement of bifunctional hydrogen electrocatalysis

To address the urgent need for non-precious metal-based catalysts in the industrial preparation and application of hydrogen energy, we present a secondary hydrothermal strategy to prepare a Mo-modified cobalt carbonate precursor, resulting in the Mo–Co/Co2N0.67 catalyst. The cobalt-based materials exhibit a layered flake structure due to molybdenum modification, exposing more active sites, while molybdenum oxide modification enhances hydrogen evolution reaction (HER) and hydrogen oxidation reaction (HOR). In alkaline HER measurements, Mo–Co/Co2N0.67 achieves a remarkable current density of 10 mA cm−2 at only 27 mV. The overall water splitting of Mo–Co/Co2N0.67 + RuO2 can reach 10 mA cm−2 at 1.52 V voltage. In alkaline HOR measurements, it exhibits the current density of 2.92 mA cm−2@0.1 V vs. RHE and an exchange current density (J0) of 2.96 mA cm−2. This work highlights the effective regulation of non-noble metal-based electrocatalysts through Mo modification, providing valuable insights for the development of efficient non-precious metal-based hydrogen electrocatalysis within the context of anion exchange membrane unitized reversible fuel cells (AEM-URFC).

Coupling RGO with magnetic components derived from basic ferric cobalt carbonate (BFCC) for efficient microwave absorption

In this work, reduced graphene oxide (RGO)-based composites loaded with magnetic CoFe2O4 (CFO) and CoFe were successfully synthesized via heat treatment of basic ferric cobalt carbonate (BFCC) under different temperatures. The impact of adding CFO and CoFe on the electromagnetic parameters and absorption properties was investigated. When 40 wt% CFO flakes and CoFe particles are added to the RGO matrix and the filler content is 20 wt% in paraffin, there gives a reflection loss of −48 dB with a 5.5 GHz absorption bandwidth at 2.1 mm thickness, and −50 dB with 4.8 GHz at 2.9 mm, respectively. The coupling of a magnetic medium can change the electromagnetic loss mechanism in the material, which ultimately affects the absorption properties of the material. This study provides a good basis for the design of composite materials of RGO as microwave absorbing materials, enabling large-scale production of high-performance absorption materials.

Insight into the key factors and mechanism of excellent tetracycline adsorption on amorphous cobalt carbonate nanosheets

The extensive use of tetracyclines (TCs) has led to their widespread distribution in the environment, causing serious harm to ecosystems because of their toxicity and resistance to decomposition. Adsorption is presently the principal approach to dispose of TCs, and the development of excellent adsorbents is crucial to TC removal. Herein, a novel amorphous cobalt carbonate hydroxide (ACCH) was successfully prepared by a one-step solvothermal method, which was identified as Co(CO3)0·63(OH)0.74·0.07H2O. The ultimate adsorption capacity of ACCH for TC reaches 2746 mg g−1, and the excellent adsorption performance can be maintained over a wide pH (3.0–11.0) and temperature (10–70 °C) range. Moreover, ACCH also exhibits a wonderful adsorption performance for other organic contaminants, such as ciprofloxacin and Rhodamine B. The TC adsorption process can be reasonably described by the pseudo-second-order kinetic model, intraparticle model and Langmuir isothermal model. The experimental results in this work suggest that the excellent adsorption performance of ACCH is ascribed to the large specific surface area, alkaline characteristics and numerous functional groups of ACCH. Accordingly, this work provides a promising strategy for the development of highly-efficient adsorbents and demonstrates their application prospects in environmental remediation.

Regulating core-shell interfacial interaction by oxygen bridging for enhancing electrochemical performance

It is crucial to design core-shell materials with interfacial interaction, which enhances their electrical conductivity, structural stability, and facilitates efficient charge transfer at the interface. In this study, two core-shell electrodes NC-O-PBA (NC: nickel cobalt layered double hydroxides, O-bridged core-shell materials) and LCCH@Ni(OH)2@PBA (LCCH: linear cobalt carbonate hydroxides, PBA: prussian blue analogs) were fabricated via interfacial contrast strategy to investigate the optimization function of oxygen at core-shell interface. Results show that as-prepared NC-O-PBA with high oxygen content creates an ideal condition for the formation of oxygen bridging. Moreover, the NC-O-PBA promotes a strong bond cooperation between core (NiCo-LDH) and shell (NiCo PBAs). The unit in PBAs can partly coordinate with the oxygen (from hydroxyl groups and interlayer ions in LDH), thus forming a strong interfacial coordination bonding between LDH and PBAs (Ni/Co(LDH)-O-CN(PBAs) or Ni/Co(LDH)-O-Ni/Co(PBAs)). Subsequently, NC-O-PBA electrode presents a high capacity of 1040.6 F g−1 at 1 A g−1 and a retention rate of 87.5% at 1500 cycles of 3 A g−1, much higher than LCCH@Ni(OH)2@PBA (462.4 F g−1 and 41.26%). Finally, in-situ Raman results demonstrated the enhanced Faraday redox reaction of NC-O-PBA. This interfacial contrast strategy and oxygen-bridged approach provide a novel idea for the development of high-performance core-shell electrode materials and facilitate deeper insights into mechanism.

Bifunctional Substrates: In‐situ Ni, Fe co‐doped Cobalt Carbonate Hydroxides for Overall Water Splitting

AbstractDeveloping highly efficient and stable electrocatalysts with large current densities for hydrogen and oxygen evolution is still challenging. Herein, Ni and Fe co‐doped cobalt carbonate hydroxide catalysts were designed in situ on the three‐dimensional porous NiFe foam through a facile one‐step hydrothermal strategy. Inductively coupled plasma atomic emission spectrum, transmission electron microscopy‐element mapping, X‐ray photoelectron spectroscopy, and DFT calculations demonstrate that the three‐dimensional NiFe foam substrate not only serves as the porous substrate, which enhances the exposed number of active sites, but also enhances the intrinsic activities of single active sites via introducing Ni and Fe dopants in the cobalt carbonate hydroxide catalyst during the hydrothermal process. The obtained hybrid electrocatalyst can be employed as a highly efficient and stable bifunctional electrocatalyst for the oxygen and hydrogen evolution reactions, with overpotentials of 340 mV and 371 mV at 1000 mA cm−2, respectively. In addition, tests in an alkaline electrolyzer revealed that the current density could reach 1000 mA cm−2 at a voltage of 2 V and maintain stable operation for 100 h.

Ni,S co-doped Cu dendrites decorated with core-shell architecture assisted by MOF and Fe0.92Co0.08S nanoflakes on nanocellulose/graphene fibers for fabrication of flexible wire-type micro-supercapacitor.

One-dimensional micro-supercapacitors (1D micro-SCs) have been regarded as an efficient energy storage system to fulfill the ever-growing need for miniaturized electronics. Designing multi-dimensional nanoarchitectures on fibrous microelectrodes is an effective strategy to build a high-performance 1D micro-SC. In this work, Ni,S-doped Cu was firstly prepared on Cu wire as a micro-sized 1D current collector through Cu electrodeposition using a H2 bubble template and then co-doped with nickel and sulfur. Benefiting from the high electrical/thermal conductivity of Cu, and the highly electroactive sites of Ni and S as well as the 3D porous architecture, the deposited Ni,S-doped Cu provided a platform for growing active substances. Thereafter, cobalt carbonate hydroxide (CoCH) pine-like nanoneedle integrated ZIF-67 polyhedrons were synthesized on a foam-like skeleton and converted into NiMoCo-layered triple hydroxide (LTH)/Ni,S-doped Cu shish-kebab type nanoarrays by applying a hydrothermal method. Finally, Ni2Mo3N-CoN/Ni,S-doped Cu was prepared via nitridation. The potent interactions and synergy between components realized a well-organized hybrid nanoarchitecture consisting of dodecahedrons decorated on needle-like arrays within a 3D framework with rich redox properties, rapid ion/electron transfer dynamics and high electroactivity. In comparison to the LTH obtained from the electrodeposition method (without the ZIF-67 precursor) and that derived from leaf-like ZIF-Co, this modified microfiber exhibited a high charge storage capacity of 1.5 mA h cm-2 (149.9 mA h cm-3 and 0.187 mA h cm-1) at 4 mA cm-2 and possesses an excellent durability of 98.4% after 5000 cycles. Additionally, FeCoS nanoflakes were electrodeposited using carbon fiber coated with an rGO-nanocellulose hydrogel (GNCH) and employed as a negative 1D microelectrode, which delivered a high specific capacitance of 1223 mF cm-2 (83 F cm-3, 232.4 mF cm-1) at 4 mA cm-2 with a superior cyclic lifespan. Ultimately, the assembled 1D flexible micro-device (Ni2Mo3N-CoN/Ni,S-doped Cu@CW//FeCoS/GNCH@CF) yielded an energy density of 7.2 mW h cm-3 at a power density of 294 mW cm-3 and outstanding cycling stability in PVA/KOH electrolyte and preserved the capacitive performance under various bending states. This research highlights that assembled 1D micro-SCs have a high potency for next-generation portable/wearable energy-supply microelectronics.

In‐situ electrochemical reconstruction of CoCO3@FeOOH for boosting high‐current‐density oxygen evolution reaction and freestanding Zn‐air battery

AbstractThe activity of electrocatalysts in the oxygen evolution reaction (OER) is crucial for the widespread applications of water electrolysis and zinc‐air batteries. Iron‐cobalt‐based catalysts attract considerably interests due to their high intrinsic activity and stability. However, it is still challenging in further promoting the OER efficiency at the high current density (500 mA cm−2) and understanding the real active sites during the OER process. In this work, the composite catalyst, cobalt carbonate (CoCO3) and iron oxyhydroxide (FeOOH), were successfully synthesized on the carbon cloth (CoCO3@FeOOH/CC) by a facile hydrothermal method. Through in‐situ electrochemical activation, the CoFe2O4/CoFeOOH catalyst (R−CoCO3@FeOOH/CC) exhibits significantly improved OER overpotential, 190 and 238 mV at the current density of 50 and 500 mA cm−2. By the in‐situ Raman spectroscopy analysis and microscopy observations, the reconstructed structure CoFe2O4/CoFeOOH was identified. Based on the highly active OER performance of R−CoCO3@FeOOH/CC, it enables the continuous operation of freestanding ZABs at the ultralow charge voltage of 1.74 V in 5 mA cm−2. These findings offer valuable insights for the design and application of high‐performance iron‐cobalt‐based OER catalysts.

Cobalt carbonate hydroxide-embedded in multi-layered holey nanoflower cross-linked with carbon nanotube for highly efficient supercapacitors with ultrahigh rate performance

In this work, bimetallic nickel-cobalt based metal organic framework (MOF) is in-situ grown on 2D laminar Co2(OH)2CO3 with multi-walled carbon nanotubes (MWCNTs) aid to form nanoflower-like hierarchical porous heterogeneous structure for advanced supercapacitor application. Benefitting from the low crystal surface energy of Co2(OH)2CO3, its intersection and connection with MOF generate convenient electron path and open channel for ionic transmission, and large contact area. The high aromaticity of MWCNTs slows down destruction for MOF structure from water molecule through providing hydrophobic environment, guaranteeing stable presence of the resulting composite in aqueous electrolyte. The synergistic effect of Ni/Co with high redox activity in bimetallic NiCo-MOF provides rapid and multiple redox reactions for enhanced capacitance. Taking full advantage of promising merits of individual components, the optimized NiCo MOF-Co2(OH)2CO3 nanosheet-MWCNT30 (NCM-NS-CNT30) composite under MWCNT dosage of 30 mg delivers greatly enhanced specific capacitance (1773 F g−1 at 1 A g−1) and obviously improved rate performance (96.5 % retention at 10 A g−1). Based on it, the fabricated hybrid supercapacitor (HSC) NCM-NS-CNT30//AC presents comparatively good energy density (30.625 Wh Kg−1), superior to most recently reported Ni, Co-based supercapacitors.

Process monitoring of cobalt carbonate precipitation by reactions between cobalt sulfate and sodium carbonate solutions to control product morphology and purity

Recovering critical elements from EV batteries is challenging as the separation is a complex process which involves different processing parameters. Cobalt (Co) is one of the metals which ensures the life of EV batteries and here we have successfully precipitated cobalt carbonate (CoCO3) by semi-batch precipitation using cobalt sulfate and sodium carbonate as reactant solutions. The precipitation of cobalt carbonate was investigated by offline Raman spectroscopy, Powder X-ray diffraction analysis, inline Focused Beam Reflectance Measurement (FBRM), and pH measurements. In addition, the effects of various factors including pH, aging time, reactant addition time, mixing speed, and temperature on cobalt carbonate precipitation and the properties of the precipitated solids were investigated. In the process of precipitation, the carbonate ions in the initial electrolyte solution were converted to bicarbonate ions during the addition of acidic cobalt sulfate solution, which consequently decreased the pH in the suspension. When the pH was lower than 8, the carbon mainly existed as bicarbonate and the cobalt carbonate started to precipitate at a high efficiency. Cobalt initially precipitated as cobalt carbonate hydroxide (Co2CO3(OH)2) at a higher pH (9–11) and converted to cobalt carbonate at a lower pH (6.5–8). The crystallite size of cobalt carbonate calculated for the different reaction conditions shows that the growth response is high at longer reactant addition time and high temperature. The morphology of the final cobalt carbonate precipitate was small single spherical crystals and their aggregates. The purity of precipitates could be increased by reducing the aggregation tendency during the precipitation.

PSVI-30 Effects of Different Cobalt Sources on Ruminal Fermentation of Lactating Dairy Cow Diets in a Dual-Flow Continuous Culture System

Abstract The objective of this study was to evaluate the effects of different sources of cobalt in a lactating dairy cow diet on in vitro ruminal fermentation. All diets provided the same amount of supplemental Co (1 mg per kg of diet DM) included in a premix with a targeted inclusion level of 2.5% of diet DM. Treatments were cobalt carbonate (CON), and three alternative Co sources; alternative source 1 (AS1), alternative source 2 (AS2), and alternative source 3 (AS3). Eight dual-flow continuous culture fermenters were used in a replicated 4 × 4 Latin square. Experimental periods were 10 d (7 d adaptation and 3 d sample collection). Composite samples of daily effluents were collected and analyzed for NH3-N, lactate, and VFA concentration as well as for nutrient digestibility. Samples of ruminal content were collected from each fermenter at 0, 1, 2, 4, 6, and 8 h after feeding to determine lactate, NH3-N, and pH kinetics. All data were analyzed using PROC MIXED of SAS and the repeated variable of time was included for pH, lactate, and NH3-N. There were neither treatment effects nor interactions between treatment and time for pH, NH3-N, and lactate concentrations, indicating a similar Co kinetics across treatments. With regards to lactate pool, we did not observe treatment effects for L-lactate; however, we observed treatment effects for D-lactate and total-lactate as seen in Table 1. Analyses of total and individual VFA, N utilization, and nutrient degradation are still undergoing, hence, it is possible that Co sources have effects on ruminal fermentation.