Eco-friendly Electrode Research Articles

Three-dimensional porous carbon-supported Co/Fe bimetallic nanoparticles derived from carboxymethyl cellulose for enhanced supercapacitor electrodes

The exploration of new high-performance, low-cost, and eco-friendly electrode materials is crucial for improving electrochemical performance. In this research, a three-dimensional interconnected porous composite electrode is synthesized, comprising bimetallic oxide of CoFe2O4 and Co3Fe7 alloy with porous carbon derived from carboxymethyl cellulose (CoFe2O4-Co3Fe7@C), through a straightforward high-temperature annealing process. Various characterizations are conducted on the CoFe2O4-Co3Fe7@C composites. The incorporation of CoFe2O4 and Co3Fe7 nanoparticles into the CMC-derived porous carbon enhances electron conduction pathways and reduces internal electrode resistance, resulting in outstanding electrochemical performance. When the CoFe2O4-Co3Fe7@C composite is carbonized at 700 °C with a current density of 0.5 A g−1, its specific capacitance reaches 3405.25 F g−1. At a power density of 321.44 W kg−1, an asymmetric supercapacitor with activated carbon as the positive and negative electrode and CoFe2O4-Co3Fe7@C-700 as the positive electrode has a maximum energy density of 187.59 Wh kg−1. Moreover, after 10,000 cycles, the composite shows 90.05 % cycling stability. This study paves the way for innovation in energy storage technology.

Bibliometric Analysis of Nanostructured Anodes for Electro-Oxidative Wastewater Treatment

Last decade, a growing emphasis on developing sustainable and environmentally friendly technologies for electro-oxidative wastewater treatment has catalyzed innovation and spurred research efforts worldwide. Researchers may explore the use of renewable energy sources to drive electrochemical processes, as well as the development of eco-friendly electrode materials for wastewater treatments. The integration of nanostructured anodes into the electrolytic system for wastewater treatment has led to significant advancements in the removal of pollutants via electro-oxidation. Despite the great number of research articles related to the development and use of nanostructured anodes for electro-oxidative wastewater treatment, to our knowledge, no bibliometric analysis has been published in this domain. Therefore, this work presents a bibliometric study of publications on the designated theme, retrieved from the Web of Science Core Collection database, which were published over the last decade. The visual and network analysis of co-authorship among authors, organizations, countries, co-citation of authors, citation of documents and sources, as well as the co-occurrence of author keywords was performed using two compatible pieces of scientometric software, namely VOSviewer (version 1.6.18) and CiteSpace (version 6.2.R4). From 2013 to 2023, there has been a gradual increase in the number of publications regarding the development and use of nanostructured anodes for electro-oxidative wastewater treatment. It suggests a steady advancement in this field. The People’s Republic of China emerges as the most productive country, and it is a leader in international collaborations. Also, the United States of America, South Korea, and European Union countries have significant impacts on the research in this domain. The development and application of nanostructured materials for urea electro-oxidation is a main and prospective research theme. This bibliometric analysis allowed for the visualization of the present landscape and upcoming trends in this research field, thereby facilitating future collaborative research endeavors and knowledge exchange.

Mixed biomass-derived multi-heteroatom doped carbon-decorated Mn3O4 for a high-performance asymmetric all solid-state supercapacitor

Recently, the development of non-conventional electrochemical energy storage technologies has attracted great attention. Herein, in accordance with green strategies for the producing renewable energy storage systems, eco-friendly electrode was successfully produced from mixed biomass precursors through carbonization and activation processes. Obtained electrode (MB-AC) as a negative and its composite (Mn3O4@MB-AC) as positive electrodes were exhibited excellent electrochemical performance with high specific capacitance of 716.49 Fg−1 at 0.75 Ag−1 and 848.21 Fg−1 at 1.0 Ag−1 respectively, in 3 M KOH electrolyte. Further, for the practical application, flexible asymmetric all-solid-state supercapacitor was made. Which offer high specific capacitance of 266.46 Fg−1 at 2 Ag−1, high energy density of 119.91 Wh kg−1 at a high-power density of 1800.08 W kg−1 within a voltage window of 1.8 V. These prominent electrochemical performances suggest that selected waste biomass materials derived carbon have considerable applications in the field of energy storage technologies.

Promoting bioremediation of brewery wastewater, production of bioelectricity and microbial community shift by sludge microbial fuel cells using biochar as anode

Seeking low-cost and eco-friendly electrode catalyst of microbial fuel cell (MFC) reactor has received extensive attention in recent decades. In this study, a sludge MFC was coupled with biochar-modified-anode (BC-300, BC-400, and BC-500) for actual brewery wastewater treatment. The physicochemical properties of biochar largely depended on the pyrolysis temperature, further affecting the removal efficiency of wastewater indicators. BC-400 MFC proved to be efficient for TN and NH4+-N removal, while the maximum removal efficiencies of COD and TP were achieved by BC-500 MFC, reaching respectively 97.14 % and 89.67 %. Biochar could promote the degradation of dissolved organic matter (DOM) in wastewater by increasing the electrochemical performances of MFC. The maximum output voltage of BC-400 MFC reached 410.24 mV, and the maximum electricity generation of 108.05 mW/m2 was also obtained, surpassing the pristine MFC (BCC-MFC) by 4.67 times. High-throughput sequencing results illustrated that the enrichment of electrochemically active bacteria (EAB) and functional bacteria (Longilinea, Denitratisoma, and Pseudomonas) in BC-MFCs, contributed to pollutants degradation and electron transfer. Furthermore, biochar affected directly the electrical conductivity of wastewater, simultaneously changing microbial community composition of MFC anode. Considering both enhanced removal efficiency of pollutants and increased power generation, the results of this study would offer technical reference for the application of biochar as MFC catalyst for brewery wastewater treatment.

Sustainable biomass conversion into activated carbon for supercapacitor devices: a promising approach toward renewable energy storage

ABSTRACT In recent years, exploitation of biomass as an economical and environmentally friendly source for the production of energy to power supercapacitor devices has gained momentum. It is a viable alternative to current methods of energy consumption and chemical production, offering a more cost-effective and sustainable solution. Additionally, biomass has an inherently high energy capacity, making it a promising source of energy for the production of supercapacitor devices. The current investigation utilizes Spathodea campanulata leaves and flowers to synthesize KOH-activated carbon (AC) through microwave approach. In this study, two types of biomass-derived materials, AC-SPL and AC-SPF, were evaluated for their suitability as electrode materials for supercapacitors. FTIR results suggested the presence of O- and N- functionalities in the synthesized carbon materials. XRD results reflected an amorphous structure with an increased crystalline size due to KOH activation. The specific capacitance values of AC-SPF were found to be 9.2F/g while for AC-SPL 6.03 F/g. The investigated samples were found to possess good physicochemical properties and promising electrochemical performance, making them suitable for use in the development of an inexpensive and eco-friendly electrode material for supercapacitor applications.

Towards Sustainable Hydrogen Peroxide Electroproduction: Activated Carbon from Sewage Sludge As an Eco-Friendly Electrode Material

Hydrogen peroxide (H2O2) has emerged as a chemical of paramount importance, finding diverse applications as a bleaching agent, medical disinfectant, and environmentally benign oxidant [1]. The industrial production of H2O2 currently relies on the anthraquinone oxidation process, primarily executed within large-scale industrial plants [1]. Herein lies a challenge— H2O2, typically concentrated to an 80% level, introduces inherent hazards concerning storage and transportation, prompting a quest for a safer alternative. One way to overcome such problems is by the in-situ electrogeneration of H2O2, which would allow an adjustable production of the chemical on demand directly for its application, avoiding storing costs and safety issues. The in-situ electrogeneration can be done by using a gaseous-diffusion electrode (GDE), which typically enables the application of elevated current densities or substantial overpotentials, consequently facilitating the generation of high concentrations of H2O2, since there is less limitation due to O2 mass transport to the electrode surface [2]. Commonly, these electrodes are constructed from amorphous carbon materials, due to their highly active surface area with oxygenated functional groups, excellent conductivity, and innate selectivity for H2O2 electroproduction. However, a notable challenge emerges – bare carbon's selectivity for H2O2 presents its highest response at high overpotentials, entailing heightened energy consumption. The studies in this field are currently focused on using these types of carbon as support for other catalytic materials that are more active and selective towards H2O2 electroproduction [3, 4]. Numerous studies in the literature have explored the use of carbon materials, with the most commonly employed carbon supports for such applications being Printex 6L (Orion) and Vulcan XC 72R (Cabot). These materials are obtained from the incomplete combustion of heavy petroleum products at high temperatures, being non-sustainable and environmentally unfriendly. A potential solution lies in the use of environmentally conscious carbon sources. While amorphous carbon can be obtained from various carbon-rich wastes through an activation process, their utility in H2O2 electrogeneration remains underexplored. This study sought to obtain activated carbon from sewage sludge, focusing on its efficacy in H2O2 electrogeneration. Acid (H3PO4) and alkaline (KOH/NaOH mixture) carbon activators were analyzed in concentrations ranging from 0 – 30 %m/v, temperatures of 400 – 900 ºC, and activation time from 0 – 2 h at the selected temperature. The obtained materials were analyzed through linear sweep voltammetry using an RRDE setup in N2-saturated and O2-saturated, in a 0.05 M K2SO4 (pH 3) electrolyte solution. Results have shown that the most successful materials for H2O2 electrogeneration were those produced under 900 ºC for 2h impregnated with 5 % m/v H3PO4 and 597 ºC, zero of plateau time impregnated with 20 % m/V mixture of KOH/NaOH in the ratio of 50.5 KOH: NaOH. These optimized materials exhibited remarkable selectivities of ≈ 90% and ≈ 81% at -0.8 V vs. Ag/AgCl, respectively. This level of electrocatalytic performance is on par with that of the commercial reference material, Printex 6L. These findings highlight the promise of our material as a viable carbon support for in-situ H2O2 electrogeneration, offering a more sustainable alternative compared to commercial black carbons. Acknowledgments The authors are sincerely grateful to the Brazilian research funding agencies, including the Brazilian National Council for Scientific and Technological Development - CNPq (grants no. 465571/2014-0, 302874/2017-8, and 427452/2018-0), São Paulo Research Foundation (FAPESP – grants no. #2023/04230-2, #2023/07750-7, 2022/04058-2, #2021/12053-8, #2019/04421-7, #2017/10118-0, and #2013/02762-5).

EDLC performance of ammonium salt-green polymer electrolyte sandwiched in metal-free electrodes

Microplastic and metal waste from electronic industries are becoming a major threat to the environment and marine ecosystem. Green processing and employing natural derived materials are solutions to this issue. In this work, an electrical double-layer capacitor (EDLC) fabricated from green polymer electrolyte (GPE) sandwiched in between two microbial cellulose-based electrodes is characterized. The eco-friendly electrode films of interconnected cellulose and multiwalled carbon nanotube (MWCNT) are obtained via harmless, inexpensive, and simple procedure. The GPE consists of methylcellulose-potato starch blend as polymer blend and ammonium iodide (NH4I) is chosen as ion provider. Glycerol serves as plasticization agent for alternative pathways enabling ionic migration. The most optimum GPE possesses good ionic conductivity of ∼ 10−3 S/cm. Ions are the dominant charge carrier in the GPE as ion transference number shown to be close to unity. Linear sweep voltammetry (LSV) analysis illustrated that the GPE is electrochemically stable up to 2.4 V. The green EDLC stores energy through non-Faradaic mechanism and the specific capacitance from charge-discharge, Ccd is influenced by the sweep rates. The EDLC can be charged and discharged up to 2 V with a stable 1000 cyclability performance. This work implied the potential of microbial cellulose-based EDLC as ideal green-based energy storage device for low voltage applications such as smart electronic textiles.

Acid substitutions for WO3 nanostructures synthesis by the hydrothermal route and its effect on physio-chemical and electrochemical properties for supercapacitors

In this study, we have developed a feasible and eco-friendly electrode material for supercapacitor (SCs) application by effectively synthesizing different morphological structures of tungsten oxide nanostructures (WO3-NSs). The concentrated acids play a crucial role in the synthesis of WO3-NSs and are employed to evaluate the electrochemical activity. The stable phase formation and the crystal structures of WO3-NSs were confirmed by thermogravimetric and X-ray analysis. From the field emission scanning electron microscope (FE-SEM), the hexagonal-shaped nanosheets, one-dimensional nanorods (1D NRs), and heterogeneous non-uniform agglomerated nanosheets were observed for the WO3-NSs. The presence of functional groups and the stretching-bending vibrations of WO bonds were detected by Fourier transform infrared, and Raman spectroscopy respectively. The transmission electron microscope (TEM) and X-ray photoelectron spectroscopy (XPS) offers a more in-depth morphological, structural, and elemental composition and electronic states investigation of the optimized WO3-NRs. Additionally, the electrochemical properties of the WO3-NSs have been examined in 1 M KOH electrolyte using Nickel Foam (NF) as a current collector. Furthermore, the M-WO3-NF electrode reveals higher specific capacity (Csp) and gravimetric capacitance (Cg) of 72 mAh/g and 600 F/g with high energy density (Ed) of 17 Wh/kg, and power density (Pd) of 321 W/kg as well as the superior Columbic efficiency (96.9 %) at 5 mA/cm2. The M-WO3 electrode exhibits 91 % capacitive retention over 5000 cycles. The M-WO3-NF is used as the cathode and activated carbon (AC) as the anode in the design of an aqueous hybrid supercapacitor (AHSC) device. Notably, the M-WO3-NF//AC-NF device offers a Pd of 1060 W/kg at an Ed of 9 Wh/kg and remarkable electrochemical stability of 80 % over 3000 charge-discharge cycles. These results highlight the excellent electrochemical functionality and advantages of the M-WO3-NRs as a promising cathode for practical energy-storage systems.

Synthesis and investigation of CoMnFeO4/reduced graphene oxide as ecofriendly electrode material for supercapacitor and its electrochemical performances

In recent years, due to the superiority of clean and renewable energy and the need for suitable storage systems for this energy, supercapacitors have been studied and investigated as a suitable storage device. For the design and manufacture of supercapacitors, the structure of the used electrode and the configuration of the device are among the most effective parameters. Therefore, in this study, the aim is to design and investigate a suitable and cost-effective nanomaterial for use in supercapacitors. For this purpose, CoMnFeO4 magnetic nanoparticles and rGO/CoMnFeO4 magnetic nanocomposite were synthesized. Then, they were investigated and identified using FT-IR, XRD, VSM, SEM, Mapping and EDX analyses. In order to investigate the supercapacitance property of these materials, various electrochemical analyses such as cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), and electrochemical impedance spectroscopy (EIS) were used. The specific capacity, the energy density, and the power density were calculated at different conditions. The specific capacity and the energy density of rGO/CoMnFeO4 at a current density of 1 A.g−1 are 380 F.g−1 and 58.18 Wh.kg−1, respectively. The results of this study generally show that CoMnFeO4 nanoparticles have the appropriate behavior as active materials for supercapacitors, and their modification with reduced graphene oxide (rGO) improved their electrochemical behavior.

Coupling with in-situ electrochemical reactive chlorine species generation and two-phase partitioning method for enhanced microalgal biodiesel production

Microalgal-based biofuel production is of great significance in alleviating energy crisis and achieving carbon neutrality. However, the excessive costs and high solvent consumption in lipids extraction from microalgal obstruct the widespread application of biodiesel in practice. Reported herein is the construction of facile strategy for lipids extraction via electrocatalytic pretreatment and a subsequent two-phase partitioning method. Electrocatalytic pretreatment method adopts the solar as power source and avoids the drying of microalgal biomass, in favor of carbon neutrality requirement. During this process, eco-friendly electrode with high specific surface area could contribute to the sufficient generation of reactive chlorine species (RCS), facilitating the outflows of intracellular lipid. As a result, assisted with two-phase partitioning method, a satisfied performance of lipid recovery (86.72 %) was obtained. Notably, compared with traditional solvent method, two-phase partitioning method greatly reduced the dosage of organic solvent, which is an economical or environmental technique.

Beyond Kolbe and Hofer-Moest: Electrochemical Synthesis of Carboxylic Anhydrides from Carboxylic Acids.

Herein we report a conceptually new non‐decarboxylative electrolysis of carboxylic acids to obtain their corresponding anhydrides as highly valuable reagents in organic synthesis. All carbon atoms of the starting material are preserved in the product in an overall redox‐neutral reaction. In a broad substrate scope of carboxylic acids the anhydrides are generated with high selectivity, which demonstrates the versatility of the developed method. Beneficially, no dehydrating reagents are required in comparison to conventional methods and the synthesis is based on uncritical starting materials using graphite and stainless steel as very inexpensive and eco‐friendly electrode materials.

Superior high-rate and cycle performances of a single-phase ferrous orthophosphate Na1.2Fe4(PO4)3 anode material for lithium-ion batteries

The development of low-cost and eco-friendly electrode materials is crucial for the next-generation rechargeable lithium-ion batteries (LIBs). Herein, the single-phase Na1.2Fe4(PO4)3 (NFP) with a monoclinic NaCo4(PO4)3-type structure is demonstrated to be a suitable anode material for LIBs. The NFP anode exhibits superior high-rate performance, releasing an initial charge capacity of 128.6 mAh g−1 at 10C and a high-capacity retention rate of 86.7% over 1500 cycles. The prominent rate performance and cycling stability of the NFP anode are attributed to the stable single-phase crystal structure and fast Li-ion diffusion verified by galvanostatic intermittent titration technique (GITT). Furthermore, the structure evolution and Li-ion diffusion pathway of the NFP anode are clarified by ex-situ X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and first-principles calculations.

Fabrication and Characterization of Environmentally Friendly Biochar Anode

Electrical power generation by means of electrochemical systems utilizing wastewaters is a global energy challenge tackling technique for which a creation of novel eco-friendly electrode materials is in high relevance. For this purpose a Rhodophyta algae derived activated biochar anode bound with a flaxseeds mucilage binder (5, 10, 20, 30 wt.%) was formed and characterized by thermogravimetric, Brunauer-Emmett-Teller (BET) analysis as well as conductivity and mechanical resistance determination. Activation technique with KOH prior to carbonization at 800 °C of algae was employed to obtain biocarbon with a large surface area. The highest specific surface area of 1298.49 m2/g was obtained with the binder-free sample and had a tendency to decrease with the increase of the binder content. It was estimated that biochar anodes are thermally stable at the temperature of up to 200 °C regardless of binder concentration. The concentration of the binder on the other hand had a significant influence in anodes mechanical resistance and electrical conductance: anode with 30 wt.% of the binder had the highest compressive strength equal to 104 bar; however, the highest conductivity was estimated in anode with 5 wt.% of the binder equal to 58 S/m. It is concluded that anode with 10 wt.% mucilage binder has the optimal properties necessary in MFC utilization.

In situ fabrication of gold nanoparticles into biocathodes enhance chloramphenicol removal

The development of highly conductive biofilms is a key strategy to enhance antibiotic removal in bioelectrochemical systems (BESs) with biocathodes. In this study, Au nanoparticles (Au-NPs) were in situ fabricated in a biocathode (Au biocathode) to enhance the removal of chloramphenicol (CAP) in BESs. The concentration of Au(III) was determined to be 5 mg/L. CAP was effectively removed in the BES containing a Au biocathode with a removal percentage of 94.0% within 48 h; this result was 1.8-fold greater than that obtained using a biocathode without Au-NPs (51.7%). The Au-NPs significantly reduced the charge transfer resistance and promoted the electrochemical activity of the biocathode. In addition, the Au biocathode showed a specifical enrichment of Dokdonella, Bosea, Achromobacter, Bacteroides and Petrimonas, all of which are associated with electron transfer and contaminant degradation. This study provides a new strategy for enhancing CAP removal in BESs through a simple and eco-friendly electrode design.

Hexagonal basalt-like ceramics LaxMg1-xTiO3 (x = 0 and 0.5) contrived via deep eutectic solvent for selective electrochemical detection of dopamine

Attributed to the increased interest in search of cost effective alternatives for electrochemical sensing materials, alkali and alkaline-earth metal oxides have seized the attention of material researchers. Herein we report the novel approach of deep eutectic solvent (DES) mediated facile solid state synthesis of pure and lanthanum doped magnesium titanate ceramics at 800 °C. The unique hexagonal basalt-like structure achieved for the La-doped ceramic material showed tremendous electrocatalytic activity towards dopamine biomolecules over a wide linear detection range of 5–50 μM. A remarkable limit of detection, 1.32 μM was attained for La-doped magnesium titanate modified glassy carbon electrode. %RSD value of 2.04 and recovery rate of 97.95 in spiked human serum ensures its promising future as a potential, cost effective and ecofriendly electrode modifier in portable dopamine sensors for point of care human serum analysis.

An eco-friendly hot-water therapy towards ternary layered double hydroxides laminated flexible fabrics for wearable supercapatteries

Abstract In recent years, a substantial advancement in flexible and wearable consumer electronics has expedited the research community to develop flexible, lightweight, and sophisticated energy storage systems via cost-effective and safe preparation methods. In this context, we propose a state-of-the-art hot-water therapy (HWT) method to trigger nickel-copper-cobalt layered double hydroxide nanosheets on flexible conductive fabric (Ni–Cu–Co LDH NSs/CF). In the proposed HWT method, de-ionized water plays a significant role in generating NSs from CF in a manner similar to germination of plants in a farmland. Exploiting the morphological and inherent traits of the active material, the Ni–Cu–Co LDH NSs/CF electrode delivered maximum areal capacity of 104.2 μAh cm−2 with an outstanding cycling stability of 124.5%. Furthermore, a supercapattery that fabricated with Ni–Cu–Co LDH NSs/CF and activated carbon delivered high areal capacitance of 232 mF cm−2 at 2 mA cm−2. Additionally, the device exhibited maximum areal energy and power densities of 0.0734 mWh cm−2 and 15 mW cm−2, respectively. A prototype flexible charge-storage station has been also designed using the fabricated supercapatteries in conjunction with a flexible solar cell panel to demonstrate the real-time feasibility of our flexible device. The prolific and state-of-the-art HWT approach can initiate substantial advancements in the rational design of eco-friendly electrode materials for wearable applications.

Hierarchical porous carbon derived from activated biochar as an eco-friendly electrode for the electrosorption of inorganic ions

Hierarchical porous carbon (HPC) as an eco-friendly electrode material was fabricated from rice husk biochar using the hard template method for electrosorption of ions. The porous structure in HPC materials can be controlled by different activation times to optimize the material physicochemical and electrochemical properties. The HPC sample achieved a high specific surface area (1839 m2 g−1), large pore volume (1.21 cm3 g−1) and 58% mesopore to total pore volume ratio. The HPC electrode exhibited excellent electrochemical properties with a high specific capacitance of 120.5 F g−1 at 5 mV s−1 in a 1 M NaCl solution as well as good reversibility for capacitive charge storage. The large ion-accessible specific surface area, interconnected pore structure among micropores and mesopores, and large mesoporosity of the HPC electrode played crucial roles in the enhancement of the electrosorption performance. The HPC electrode exhibited a high electrosorption capacity of 8.11 mg g−1 and mean deionization rate of 0.92 mg g−1 min−1 for 20 mM NaCl in single-pass capacitive deionization. The associated charge efficiency and energy consumption were 48.1% and 0.064 kWh mol−1, respectively, indicating a low energy requirement of water desalination. Furthermore, the HPC electrode showed good regeneration ability in consecutive cycles for the removal of inorganic pollutants, i.e., NH4+, Mg2+ and Cu2+, with electrosorption capacities of 1.54, 1.53 and 0.52 mg g−1, respectively. Consequently, HPC from tailored activated rice husk biochar can provide a new opportunity to achieve high-performance electrosorption in various water and wastewater treatment processes.

Ultrafast kinetics net electrode assembled via MoSe2/MXene heterojunction for high-performance sodium-ion batteries

Establishing advanced sodium-ion batteries (SIBs) with high energy density and eco-friendly electrode materials are still far from satisfactory due to the large-size of sodium-ions and sluggish redox kinetics during electrochemical processes. Herein, a novel ultrafast kinetics net electrode assembled via MoSe2/MXene heterojunction is synthesized by a simple hydrothermal method followed by thermal annealing. Featuring the Van der Waals force interaction between MoSe2 and MXene, the volumetric change during the sodium ions insertion/extraction courses is effectively restrained, and the reaction kinetics is greatly enhanced further. Meanwhile, both the high electrical and ion conductivity (lower diffusion barrier between Na+/MXene ~0.066 eV) provided by the unique MXene based net heterostructure of our hybrid materials, as evidenced by DFT calculations, are beneficial to the transportation of sodium ions, thus enabling an outstanding rate and long-cycling capability. As a result, the fabricated cells exhibit high reversible capacities of 490 mAh g−1 at 1 A g−1, as well as 250 mAh g−1 at a high current of 10 A g−1 with a coulombic efficiency of 99.8%, indicating the excellent electrochemical performance of our hybrid materials, especially at high current. This novel net MoSe2/MXene heterostructure, combined with our simple synthesis strategy together, are expected to have great potential in sodium-ions storage application.

Alginic acid-derived mesoporous carbonaceous materials (Starbon®) as negative electrodes for lithium ion batteries: Importance of porosity and electronic conductivity

Alginic acid-derived mesoporous carbonaceous materials (Starbon® A800 series) were investigated as negative electrodes for lithium ion batteries. To this extent, a set of mesoporous carbons with different pore volume and electronic conductivity was tested. The best electrochemical performance was obtained for A800 with High Pore Volume (A800HPV), which displays both the highest pore volume (0.9 cm3 g−1) and the highest electronic conductivity (84 S m−1) of the tested materials. When compared to a commercial mesoporous carbon, A800HPV was found to exhibit both better long-term stability, and a markedly improved rate capability. The presence of a hierarchical interconnected pore network in A800HPV, accounting for a high electrolyte accessibility, could lay at the origin of the good electrochemical performance. Overall, the electronic conductivity and the mesopore size appear to be the most important parameters, much more than the specific surface area. Finally, A800HPV electrodes display similar electrochemical performance when formulated with or without added conductive additive, which could make for a simpler and more eco-friendly electrode processing.

A Polyanion Host as a Prospective High Voltage Cathode Material for Sodium Ion Batteries

It is essential to develop efficient electrode materials for sodium in batteries, which are currently being considered as a promising alternative to lithium-ion batteries. In this work, we are presenting NaMnBO3 nanoparticles with conductive carbon matrix (C-NMB) synthesized by urea-assisted hydrothermal method used as a potential cathode material in sodium ion batteries. The C-NMB electrode delivered discharge capacities of 116 mAh g−1, 97 mAh g−1, and 52 mAh g−1 at 0.2 C, 0.5 C, and 2 C rates, respectively and exhibited excellent cyclic behavior at all current densities. Further, the C-NMB electrode demonstrated the best electrochemical stability among other polyanion cathodes, with a capacity fade of 0.06% per cycle at 2 C after 250 cycles with more than 99% coulombic efficiency. X-ray photoelectron spectroscopy revealed that the reduction in oxygen containing surface functionalities (carboxyl groups) further increased the electrical conductivity of the NMB materials. The ex-situ XRD studies after first initial charge and discharge steps reveals that the hexagonal C-NMB electrode displays a topotactic sodium storage mechanism. These outcomes will contribute to the progress of developing low cost, eco-friendly electrode materials for sodium-ion batteries.