Fabricating Fe3O4/Fe/Biocarbon Fibers using Cellulose Nanocrystals for High-Rate Li-ion Battery Anode

Overlooked Promising Green Features of Electrospun Cellulose-Based Fibers in Lithium-Ion Batteries

Lithium-ion batteries (LIBs) are accounted as promising power tools, applicable in a wide range of energy-based equipment, from portable devices to electric vehicles. Meanwhile, approaching a cost-effective, environmentally friendly, and safe LIB array has remained sluggish yet. In this regard, cellulose, as a nontoxic natural renewable polymer, has provided a stable and cohesive electrode structure with excellent mechanical stability and reduced electrode cracking or delamination during cycling. Additionally, the porous configuration of the cellulose allows for efficient and faster ion transport as a separator component. Miniaturizing cellulose and its derivatives have revealed more fabulous characteristics for the anode, cathode, and separator resulting from the increased surface-to-volume ratio and superior porosity, as well as their thin and lightweight architectures. The focal point of this review outlines the challenges relating to the extraction and electrospinning of cellulose-based nanofibers. Additionally, the efforts to employ these membranes as the LIBs' components are elucidated. Correspondingly, despite the great performance of cellulose-based LIB structures, a research gap is sensed in this era, possibly due to the difficulties in processing the electrospun cellulose fibers. Hence, this review can provide a source of recent advancements and innovations in cellulose-based electrospun LIBs for researchers who aim to develop versatile battery structures using green materials, worthwhile, and eco-friendly processing techniques.

Regeneration of porous Fe3O4 nanosheets from deep eutectic solvent for high-performance electrocatalytic nitrogen reduction

The production of ammonia through electrocatalytic nitrogen reduction reaction (NRR) is environmentally friendly and energy-saving, but it still suffers from the low NH₃ yield rate and poor selectivity. Herein, enlightened by the unique solubility of Fe₃O₄ in deep eutectic solvent (DES), we, for the first time, reported a DES-based regeneration strategy to fabricate porous Fe₃O₄ nanosheets utilizing commercial Fe₃O₄ powder as raw materials. The as-regenerated porous Fe₃O₄ nanosheets exhibited satisfactory electrocatalytic performance toward NRR, affording a NH₃ yield rate of 12.09 μg h^-1 mg^-1_cat along with an outstanding Faradaic efficiency (FE) of 34.38% at -0.1 V versus reversible hydrogen electrode (RHE), in the 0.1 M Na₂SO₄ electrolyte. The superior electrocatalytic activity of the as-regenerated Fe₃O₄ nanosheets mainly resulted from their unique sheet-like morphology with large active surface area, high porosity, and abundant oxygen vacancies. Our proposed DES-based regeneration strategy opens a new avenue for the construction of high-performance electrocatalyst from commercial raw materials, holding great promise in NRR.

Recent Advances in Functional Materials through Cellulose Nanofiber Templating

Advanced templating techniques have enabled delicate control of both nano- and microscale structures and have helped thrust functional materials into the forefront of society. Cellulose nanomaterials are derived from natural polymers and show promise as a templating source for advanced materials. Use of cellulose nanomaterials in templating combines nanoscale property control with sustainability, an attribute often lacking in other templating techniques. Use of cellulose nanofibers for templating has shown great promise in recent years, but previous reviews on cellulose nanomaterial templating techniques have not provided extensive analysis of cellulose nanofiber templating. Cellulose nanofibers display several unique properties, including mechanical strength, porosity, high water retention, high surface functionality, and an entangled fibrous network, all of which can dictate distinctive aspects in the final templated materials. Many applications exploit the unique aspects of templating with cellulose nanofibers that help control the final properties of the material, including, but not limited to, applications in catalysis, batteries, supercapacitors, electrodes, building materials, biomaterials, and membranes. A detailed analysis on the use of cellulose nanofibers templating is provided, addressing specifically how careful selection of templating mechanisms and methodologies, combined toward goal applications, can be used to directly benefit chosen applications in advanced functional materials.

Template-assisted loading of Fe3O4 nanoparticles inside hollow carbon "rooms" to achieve high volumetric lithium storage

The design of electrodes with simultaneously high compaction density, developed porosity, and structural stability has always been a challenge so as to meet the demand of high volumetric performance lithium ion storage devices. In this paper, we demonstrate a new compositing method for hollow carbon "room" loading of Fe₃O₄ nanoparticles (HCR@Fe₃O₄) with the assistance of Na₂CO₃ salt crystal templates. The as-obtained HCR@Fe₃O₄ composites have a massive compaction density (1.79 g cm^-3), abundant multimodal pores (1.26 cm³ g^-1), and a large content of Fe₃O₄ (64.2 wt%), which leads to excellent volumetric capacitive performance. More importantly, the unique compositing model not only provides a fast transmission channel for Li⁺ but also alleviates the mechanical strain efficiently through the cavity between the Fe₃O₄ nanoparticles and the carbon wall. When evaluated as an anode of lithium ion batteries, the resultant HCR@Fe₃O₄ electrode exhibits a remarkable volumetric capacity of 2044 mA h cm^-3 at 0.2 A g^-1 and a stable cycle life of 828 mA h cm^-3 after 1000 cycles at 5 A g^-1. The assembled HCR@Fe₃O₄//AC lithium ion hybrid capacitor device exhibits a high energy density of 173 W h L^-1 at a power density of 190 W L^-1, demonstrating its high-level integrated volumetric density/power density.

A review on Fenton process for organic wastewater treatment based on optimization perspective

Water pollution caused by organic wastewater has become a serious concern worldwide. Fenton oxidation process is one of the most effective and suitable methods for the abatement of organic pollutants. However, the process has three obvious shortcomings: the narrow working pH range, the high costs and risks associated with handling, transportation and storage of reagents (H₂O₂ and catalyst), the significant iron sludge related second pollution. In order to overcome these shortcomings, various optimized Fenton processes have been widely studied. Therefore, a summary of the study status of Fenton optimization processes is necessary to develop a novel and high efficiency organic wastewater treatment method. Based on the optimization perspective, taking shortcomings of Fenton process as a breakthrough, the fundamentals, advantages and disadvantages of single Fenton optimization processes (heterogeneous Fenton, photo-Fenton and electro-Fenton) for organic wastewater treatment were reviewed and the corresponding reaction mechanism diagrams were drawn in this paper. Then, the feasibility and application of the coupled Fenton optimization processes (photoelectro-Fenton, heterogeneous electro-Fenton, heterogeneous photoelectro-Fenton, three-dimensional electro-Fenton) for organic wastewater treatment were discussed in depth. Additionally, the effect of some important operation parameters (pH and catalyst, H₂O₂, organic pollutants concentration) on the degradation efficiency of organic pollutants was studied to provide guidance for the optimization of operation parameters. Finally, the possible future research directions for optimized Fenton processes were given. The review aims to assist researchers and engineers to gain fundamental understandings and critical view of Fenton process and its optimization processes, and hopefully with the knowledge it could bring new opportunities for the optimization and future development of Fenton process.

FeO x -Based Materials for Electrochemical Energy Storage

Iron oxides (FeO x ), such as Fe2O3 and Fe3O4 materials, have attracted much attention because of their rich abundance, low cost, and environmental friendliness. However, FeO x , which is similar to most transition metal oxides, possesses a poor rate capability and cycling life. Thus, FeO x -based materials consisting of FeO x , carbon, and metal-based materials have been widely explored. This article mainly discusses FeO x -based materials (Fe2O3 and Fe3O4) for electrochemical energy storage applications, including supercapacitors and rechargeable batteries (e.g., lithium-ion batteries and sodium-ion batteries). Furthermore, future perspectives and challenges of FeO x -based materials for electrochemical energy storage are briefly discussed.

Oxygen Vacancy Promoted Heterogeneous Fenton-like Degradation of Ofloxacin at pH 3.2-9.0 by Cu Substituted Magnetic Fe3O4@FeOOH Nanocomposite

To develop an ultraefficient and reusable heterogeneous Fenton-like catalyst at a wide working pH range is a great challenge for its application in practical water treatment. We report an oxygen vacancy promoted heterogeneous Fenton-like reaction mechanism and an unprecedented ofloxacin (OFX) degradation efficiency of Cu doped Fe₃O₄@FeOOH magnetic nanocomposite. Without the aid of external energy, OFX was always completely removed within 30 min at pH 3.2-9.0. Compared with Fe₃O₄@FeOOH, the pseudo-first-order reaction constant was enhanced by 10 times due to Cu substitution (9.04/h vs 0.94/h). Based on the X-ray photoelectron spectroscopy (XPS), Raman analysis, and the investigation of H₂O₂ decomposition, ^•OH generation, pH effect on OFX removal and H₂O₂ utilization efficiency, the new formed oxygen vacancy from in situ Fe substitution by Cu rather than promoted Fe³⁺/Fe²⁺ cycle was responsible for the ultraefficiency of Cu doped Fe₃O₄@FeOOH at neutral and even alkaline pHs. Moreover, the catalyst had an excellent long-term stability and could be easily recovered by magnetic separation, which would not cause secondary pollution to treated water.

Visible-light-sensitive titanium dioxide nanoplatform for tumor-responsive Fe2+ liberating and artemisinin delivery

Artemisinin is a kind of Fe²⁺-dependent drugs. Artemisinin and Fe²⁺ co-transport systems can improve its anti-tumor effect. In this study, a visible light-sensitive nanoplatform (HA-TiO₂-IONPs/ART) was developed. Detailed investigation demonstrated that HA-TiO₂-IONPs/ART could realize Fe²⁺ and artemisinin synchronous co-delivery and tumor-responsive release. This feature enhanced the anti-tumor efficiency of artemisinin significantly. In vitro results proved that hyaluronic acid modification could improve the biocompatibility, dispersion stability and cytophagy ability of nanocarriers. Furthermore, this drug delivery system could generate reactive oxygen species under visual light irradiation. In vitro and in vivo experiments demonstrated that HA-TiO₂-IONPs/ART combining with laser irradiation displayed the best anti-tumor efficacy. This study affords a promising idea to improve the curative efficiency of artemisinin analogs for cancer therapy.

Graphene-Embedded Co3O4 Rose-Spheres for Enhanced Performance in Lithium Ion Batteries

Co₃O₄ has been widely studied as a promising candidate as an anode material for lithium ion batteries. However, the huge volume change and structural strain associated with the Li⁺ insertion and extraction process leads to the pulverization and deterioration of the electrode, resulting in a poor performance in lithium ion batteries. In this paper, Co₃O₄ rose-spheres obtained via hydrothermal technique are successfully embedded in graphene through an electrostatic self-assembly process. Graphene-embedded Co₃O₄ rose-spheres (G-Co₃O₄) show a high reversible capacity, a good cyclic performance, and an excellent rate capability, e.g., a stable capacity of 1110.8 mAh g^-1 at 90 mA g^-1 (0.1 C), and a reversible capacity of 462.3 mAh g^-1 at 1800 mA g^-1 (2 C), benefitted from the novel architecture of graphene-embedded Co₃O₄ rose-spheres. This work has demonstrated a feasible strategy to improve the performance of Co₃O₄ for lithium-ion battery application.

Biomass-derived nanostructured carbons and their composites as anode materials for lithium ion batteries

This review focuses on the derivation of nanostructured carbons and their composite materials from biomass materials for lithium ion battery anodes.

Fabricating three-dimensional mesoporous carbon network-coated LiFePO4/Fe nanospheres using thermal conversion of alginate-biomass

Three-dimensional mesoporous carbon network-coated LiFePO₄/Fe nanospheres with high-rate capability.

Three dimensional hierarchically porous crystalline MnO2 structure design for a high rate performance lithium-ion battery anode

A hierarchically porous crystalline MnO₂ anode was applied to a lithium ion battery and exhibited long cycling life and high rate performance.

Design and synthesis of one-dimensional Co3O4/Co3V2O8 hybrid nanowires with improved Li-storage properties

A new nanostructure of one-dimensional Co₃O₄/Co₃V₂O₈ hybrid nanowires directly grown on Ti substrates with improved electrochemical Li-storage properties are successfully prepared by a simple hydrothermal strategy.

Facile synthesis of a nickel vanadate/Ni composite and its electrochemical performance as an anode for lithium ion batteries

Ni₃V₂O₈/Ni composites are synthesized by a simple hydrothermal route, and show high-rate capability and outstanding long-life cycling stability as a new anode material for Li-ion batteries.