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Microbial fuel cell (MFC) has been regarded as a promising green and clean electricity generation device. The anode plays a crucial role in the electricity generation process within the MFC. This study employed a hydrothermal method for the doping of sulfur onto MXene nanosheets to alleviate the stacking, followed by an in situ polymerization process to fabricate sufur-doped MXene/polypyrrole (S–MXene/PPy) composite hydrogel on carbon felt (CF). The MFC constructed with this anode exhibited the highest power density of 8.05 W m−3 and a maximum output voltage of 646 mV, higher than that of MXene/PPy (623 mV, 6.03 W m−3), PPy (594 mV, 4.91 W m−3), and unmodified CF (574 mV, 4.05 W m−3). This improved performance can be attributed to the reduction of charge transfer resistance in the material while improving the bacteria affinity, leading to enhanced extracellular electron transfer (EET) efficiency. High-throughput sequencing indicates that the excellent biocompatibility significantly promotes the attachment and growth of electroactive microorganisms (Geobacter, 45.34%) on the S–MXene/PPy anode. This study demonstrates that S–MXene/PPy hydrogel has good potential as an anode from the perspective of MFC electricity generation and microbial analysis. [ABSTRACT FROM AUTHOR]

Iron oxide (Fe2O3) emerges as a highly attractive anode candidate among rapidly expanding energy storage market. Nonetheless, its considerable volume changes during cycling as an electrode material result in a vast reduced battery cycle life. In this work, an approach is pioneered for preparing high-performance Fe2O3 anode materials, by innovatively synthesizing a triple-layer yolk-shell Fe2O3 uniformly coated with a conductive polypyrrole (Ppy) layer (Fe2O3@Ppy-TLY). The uniform polypyrrole coating introduces more reaction sites and adsorption sites, and maintains structure stability through charge-discharge process. In the uses as lithium-ion battery electrodes, Fe2O3@Ppy-TLY demonstrates high reversible specific capacity (maintaining a discharge capacity of 1375.11 mAh·g−1 after 500 cycles at 1 C), exceptional cycling stability (retaining the steady charge-discharge performance at 544.33 mAh·g−1 after 6000 ultrafast charge-discharge cycles at a 10 C current density), and outstanding high current charge-discharge performance (retaining a reversible capacity of 156.75 mAh·g−1 after 10000 cycles at 15 C), thereby exhibiting superior lithium storage performance. This work introduces innovative advancements for Fe2O3 anode design, aiming to enhance its performance in energy storage fields. [ABSTRACT FROM AUTHOR]

Silicon-carbon materials have broad development prospects as negative electrode materials for lithium-ion batteries. In this paper, polyvinyl butyral (PVB)-based carbon-coated silicon (Si/C) composite materials were prepared using PVB-coated Si particles and then high-temperature carbonization methods. Furthermore, the PVB-based carbon-coated silicon/artificial graphite composite materials (Si/C-Gr) were prepared by using artificial graphite as conductive skeleton. And the electrochemical and battery performances of Si/C and Si/C-Gr composite materials as negative electrode materials of lithium-ion batteries were investigated in detail. The results showed that PVB-based carbon was uniformly coated on the surface of silicon particles, and the electrochemical performance and battery performance of the Si/C composite material was improved with the increasing proportion of PVB in the reaction feed. With the introduction of artificial graphite, the constructed ternary composite of Si/C-Gr as anode exhibited a further improved electrochemical performances, such as cycling stability, rate performance, and coulombic efficiency. Specially, the Si/C-Gr (1:30:0.7) composite anode has a discharge specific capacity of 1239.9 mAh/g in the first cycle and 922.9 mAh/g in the 100th cycles at a current density of 0.1 A/g. And the corresponding coulombic efficiency was 84.5% in the first cycle and maintained at around 98% after 100 cycles. The average discharge specific capacity was 1045.5, 796.08, 688.75, 507.09, and 479.11 mAh/g at the current rate of 0.1, 0.2, 0.4, 0.8, and 1 A/g, respectively. This is attributed to the addition of artificial graphite forming an effective conductive skeleton structure, which enhanced the structural stability of the composite material and improved the electronic conductivity of the electrode material. Also, PVB as functional coating polymer improved the dispersion of Si particles on the surface of graphite. All above reasons enabled the electrode materials to have good electrochemical performances. [ABSTRACT FROM AUTHOR]

Saline water electrolysis is an appealing strategy for hydrogen production, attracting more attention in recent years. NiFe-based electrodes exhibit promise as catalysts for saline water electrolysis. Nevertheless, they suffer from the inferior service life of the oxygen evolution reaction (OER). Herein, we report an oxygen-evolution electrode consisting of a sulfate-modulated nickel-iron hydroxide (NiFeOOH) affording as the catalytic active layer and Fe-Ni3S2 as the corrosion-proof layer. The developed electrode only requires overpotentials of 220 and 292 mV to deliver the current density of 10 and 500 mA·cm−2, respectively. More importantly, it presents long-term stability exceeding 140 and 100 h in 1 M KOH at high current densities of 500 and 1000 mA·cm−2, respectively, as well as 120 h for saline water electrolysis at 100 mA·cm−2. Experimental results reveal that the generated sulfate plays an indispensable role in improving stability and corrosion resistance. We assembled and tested an anion exchange membrane electrolyzer with Pt/C and NiFeS/NIF as the cathode and anode, respectively, under industrial conditions. This overall water-splitting electrolyzer achieves an impressive energy conversion efficiency of 75% ± 0.5%. This report offers fresh insights into the design of stable NiFe-based electrodes, which may further promote its practical applications for saline water electrolysis. [ABSTRACT FROM AUTHOR]

MnO has many advantages as an anode material for lithium-ion electrochemical energy storage system, but the poor cycle performance of MnO anode material is always a pain point. In this work, MnTiO3 is used as a coating layer and thin-layer graphite (TLG) is introduced as a skeleton to achieve a significant improvement in the cycle performance of MnO anode materials. MnO@MnTiO3/TLG materials have been systematically characterized, which fully illustrates the existence of the coating layer and framework structure and also clarifies the positive influence of this special structure on the material properties. At the current density of 100 mA g−1, the initial discharge capacity of the material is about 600 mAh g−1, the initial coulombic efficiency is about 71%, and the capacity is not significantly degraded after 100 cycles. Long-term cycling stability of MnO@MnTiO3/TLG is excellent: the capacity retention rate is around 90% after 300 cycles at 200 mA g−1. The improvement of material performance is mainly due to the synergistic effect of MnTiO3 coating layer and TLG supporter, alleviating the structural change and collapse during the charge/discharge cycles. [ABSTRACT FROM AUTHOR]

Tin dioxide-based high-performance anode materials for lithium-ion batteries have been a hot research topic in recent years. In this study, nitrogen-doped and double-layered SnO2@NC hollow spheres were prepared via simple and convenient method using carbon spheres as template. A series of products were obtained by varying additive amount of dopamine. When tested in the current density of 400 mA g−1, SnO2@NC-3 can provide a robust reversible capacity of 697.7 mAh g−1 after 270 cycles. The discharge capacity can remain 640.8 mAh g−1 after 800 cycles at 1000 mA g−1. Above excellent electrochemical properties were attributed to the synergistic effect between nitrogen-doped carbon and nanosized-SnO2 particles. The hollow structure can not only effectively buffer the structure crushing of the electrode in the process of charge and discharge, but also facilitate the electron diffusion by improving the electronic conductivity. Therefore, the unique nitrogen-doped and double-layered tin dioxide is a promising anode material for lithium-ion battery. [ABSTRACT FROM AUTHOR]

The prevalence of polyfluoroalkyls and perfluoroalkyls (PFAS) represents a significant challenge, and various treatment techniques have been employed with considerable success to eliminate PFAS from water, with the ultimate goal of ensuring safe disposal of wastewater. This paper first describes the most promising electrochemical oxidation (EO) technology and then analyses its basic principles. In addition, this paper reviews and discusses the current state of research and development in the field of electrode materials and electrochemical reactors. Furthermore, the influence of electrode materials and electrolyte types on the deterioration process is also investigated. The importance of electrode materials in ethylene oxide has been widely recognised, and therefore, the focus of current research is mainly on the development of innovative electrode materials, the design of superior electrode structures, and the improvement of efficient electrode preparation methods. In order to improve the degradation efficiency of PFOS in electrochemical systems, it is essential to study the oxidation mechanism of PFOS in the presence of ethylene oxide. Furthermore, the factors influencing the efficacy of PFAS treatment, including current density, energy consumption, initial concentration, and other parameters, are clearly delineated. In conclusion, this study offers a comprehensive overview of the potential for integrating EO technology with other water treatment technologies. The continuous development of electrode materials and the integration of other water treatment processes present a promising future for the widespread application of ethylene oxide technology. [ABSTRACT FROM AUTHOR]

In this work, we aim to study and improve the electrochemical performance of a unique thin film-structured composite nitrogen-doped graphene (NGr) combined with NiO/TiO2 hollow nanospheres coupled by synergistic hydrothermal method. NGr@NiO/TiO2 nanocomposites have been successfully synthesized as indicated by their characteristics through several rational characterization techniques such as the morphological shape of NiO/TiO2 hollow nanospheres that are evenly distributed on the surface of N-graphene with particle distribution in the range of 79.78–362.13 nm with an average diameter of 130 nm. In addition, the crystal structures of carbon from NGr, NiO, and TiO2 (anatase and rutile) have been confirmed and proven by spectra showing the presence of C–N stretching primary amides (1400 cm−1), Ni–O stretching (700 cm−1) and Ti–O–Ti bond (425 cm−1), respectively. To enhance the performance of cyclic voltammetry (CV) in electrochemical testing, adjustments are made to parameters such as cycle effect, scan rate, and composition, ensuring the production of reversible voltammograms under each condition. The results indicate that reversible voltammograms are observed under each condition, with a composite ratio of 80:15:5 (wt%). Slower scan rates are associated with higher specific capacity (Cps), with the Cps values for the NGr@NiO/TiO2 electrode being 741.02 F/g (80:10:10), 408.53 F/g (80:5:10), and 839.83 F/g (80:15:5), respectively. However, the highest Cps is recorded for NGr@NiO at 1959.71 F/g. Based on these findings, it is revealed that further comprehensive electrochemical testing of the NGr@NiO/TiO2 nanocomposite is necessary, to fully explore its potential and applicability in the development of alkaline ion batteries (AIBs) such as Li/Na/K. [ABSTRACT FROM AUTHOR]

The best choice today for a realistic method of increasing the energy density of a metal-ion battery is to find novel, effective electrode materials. In this paper, we present a theoretical investigation of the properties of hitherto unreported two-dimensional B 3 C 5 and N 3 C 5 bilayer systems as potential anode materials for lithium-ion batteries. The simulation results show that N 3 C 5 bilayer is not suitable for anode material due to its thermal instability. On the other hand B 3 C 5 is stable, has good electrical conductivity, and is intrinsically metallic before and after lithium intercalation. The low diffusion barrier (0.27 eV) of Li atoms shows a good charge and discharge rate for B 3 C 5 bilayer. Moreover, the high theoretical specific capacity (579.57 mAh/g) connected with moderate volume expansion effect during charge/discharge processes indicates that B 3 C 5 is a promising anode material for Li-ion batteries. [ABSTRACT FROM AUTHOR]

This study explores the potential applications of graphene oxide frameworks (GOFs) in Na-ion batteries using density functional theory calculations. The GOF's graphene layers are linked by benzenediboronic acid pillars. Ab-initio molecular dynamics simulations demonstrate the thermal stability of the structures. The study calculates adsorption and barrier energy, storage capacity, and open-circuit voltage. The results predict the high mobility of Na in GOF due to the low energy barrier. The layered structure of GOF enables the intercalation of Na-ions. GOF has a Na storage capacity of 947 mAh/g in the form of Na21C36, which is higher than the reported values for graphite and some other two-dimensional carbon-based materials. The transition from semiconductor to metal, which is an essential condition for the diffusion of ions within the anode material, occurs after Na adsorption. Therefore, GOFs are a promising anode material with high efficiency for Na-ion batteries. [ABSTRACT FROM AUTHOR]

Transition metal oxide MnFe2O4 is considered a promising anode material for Li-ion batteries owing to its high theoretical specific capacity. However, this material has two bottleneck problems, i.e., poor conductivity and serious volume expansion during cycling. In this work, MnFe2O4 nanoparticles were successfully encapsulated in the matrix of N-doped porous carbon via a sol–gel method. As a result, the N-doped carbon matrix enhances the electronic conductivity of the composites. The special porous structure increases the contact area between the electrode material and the electrolyte and facilitates the rapid infiltration of the electrolyte. At a calcination temperature of 400 °C, the MnFe2O4/C composite shows a high initial discharge specific capacity of 1207.0 mAh g−1 at 0.2 A g−1 and retains a reversible specific capacity of 1100.1 mAh g−1 after 200 cycles. The simple design of metal oxide nanomaterials encapsulated in N-doped porous carbon provides a new direction for improving the electrochemical performance of electrode materials for Li-ion batteries. A brief abstract: MnFe2O4 nanoparticles were successfully encapsulated in the matrix of N-doped porous carbon via a sol–gel method. At a calcination temperature of 400 °C, the MnFe2O4/C composite shows a high initial discharge specific capacity of 1207.0 mAh g−1 at 0.2 C and retains a reversible specific capacity of 1100.1 mAh g−1 after 200 cycles. [ABSTRACT FROM AUTHOR]

Aqueous rechargeable batteries are the promising energy storge technology due to their safety, low cost, and environmental friendliness. Ammonium ion (NH4+) is an ideal charge carrier for such batteries because of its small hydration radius and low molar mass. In this study, VO2·xH2O with rich oxygen defects (d-HVO) is designed and synthesized, and it exhibits unique nanoarray structure and good electrochemical performances for NH4+ storge. Experimental and calculation results indicate that oxygen defects in d-HVO can enhance the conductivity and diffusion rate of NH4+, leading to improved electrochemical performances. The most significant improvement is observed in d-HVO with 2 mmol thiourea (d-HVO-2) (220 mAh·g−1 at 0.1 A·g−1), which has a moderate defect content. A full cell is assembled using d-HVO-2 as the anode and polyaniline (PANI) as the cathode, which shows excellent cycling stability with a capacity retention rate of 80% after 1000 cycles and outstanding power density up to 4540 W·kg−1. Moreover, the flexible d-HVO-2∥PANI battery, based on quasi-solid electrolyte, shows excellent flexibility under different bending conditions. This study provides a new approach for designing and developing high-performance NH4+ storage electrode materials. [ABSTRACT FROM AUTHOR]

In this work, phenolic resin (PR) -based carbon aerogel composites reinforced with aluminum silicate ceramic fibers were obtained using the conventional sol-gel method with the carbonization technique. The experiment results showed that carbon aerogel with stable morphology was obtained by drying the PR wet gel at room temperature. Reactant ratios affected the microstructure and overall performance of carbon aerogels. The overall discharge capacity of the obtained carbon aerogel specimens was maintained at 330 mAh g−1 when the mass ratio of phenolic resin to curing agent was 8:1. The growth of aerogel particles was guided during the curing reaction. A three-dimensional network structure with ceramic fibers as the core was formed in PR/CF. The ceramic fibers suppressed the shrinkage of the samples, and the ceramic fibers improved the mechanical properties of the samples. [ABSTRACT FROM AUTHOR]

Biomass-derived carbon material has the advantages of economy and high reversible capacity, and become the research hotspot of anode material for sodium-ion batteries (SIBs). Herein, a facile process to prepare carbon material derived from pyrolysis of cotton stalks was reported. As an anode material for SIBs, the sample shows reversible capacity of 76 mA h g−1 after 500 cycles at 0.05 A g−1. In addition, it has specific capacity of 70 mA h g−1 after 1000 cycles at a current density of 0.1 A g−1. This paper provides a new idea to produce carbon material from biomass waste for energy storage and makes a certain contribution to the sustainable development of waste resources. [ABSTRACT FROM AUTHOR]

The T–x phase diagram of the quasi-binary system was refined and the isothermal cross section of the ternary system at 298 K was constructed. The equilibrium phase regions of in the solid state are determined with the participation of boundary binary oxides and four intermediate ternary compounds , , and . Using the density functional theory (DFT LSDA) method, the formation energies of the indicated ternary compounds of the system were calculated and the dependence of on the composition was plotted. Ab initio modeling of supercells based on M-doped anode material based on the () compound with a monoclinic structure (m) was carried out. It has been shown that partial substitution of cations and oxygen in the structure increases the efficiency of a lithium-ion battery () both by stabilizing the structure and by increasing the diffusion rate of . Due to the contribution of d-orbitals ( 4d orbitals) to the exchange energy, partial polarization of electronic states occurs and the electronic conductivity of increases. The formation of oxygen vacancies in the crystal lattice, as in binary oxides, can create donor levels and improve the transport of and electrons. M-doping of the structure by replacing cations, in particular lithium, with Zr or Nb atoms noticeably reduces the band gap () of supercells. In this case, in the band structure, the Fermi level shifts to the conduction band and the band gap narrows. Decreasing the value increases the electronic and lithium-ion conductivity of supercells. [ABSTRACT FROM AUTHOR]

SiOC anode materials are widely studied due to their good stability, high theoretical specific capacity, and low cost, which make them attractive as potential anode materials. However, the poor conductivity of SiOC limits its application in lithium-ion batteries. In order to improve the electrochemical properties of SiOC materials, SiOC/carbon nanotube (CNT) nanocomposites with different content were prepared by the wet chemical method. The effects of CNTs on the microstructure and electrochemical performance of the nanocomposites were studied. When the current density was 0.2 C, the reversible capacity of SiOC/CNTs-3 composites reached 517.01 mAh/g after 100 cycles, while that of SiOC was only 413.52 mAh/g. The results show that the introduction of CNTs improved the electrochemical properties of SiOC materials. Therefore, the study provides an effective strategy for improving the electrochemical properties of silicon-based anode materials. [ABSTRACT FROM AUTHOR]

The Bi2WO6/carbon (BWO/C) micron flowers are synthesized by hydrothermal method combined with heat treatment using the sodium tungstate and bismuth nitrate as well as palm bark carbon as raw materials. The palm bark carbon was prepared firstly by hydrothermal method combined with high-temperature treatment. The BWO/C was characterized by XRD, SEM, and TEM techniques. The BWO/C took on morphology of irregular micron flowers with an average diameter of about 0.5 μm which were assembled from nanoparticles. The BWO/C was investigated as anode material by battery test system and electrochemical workstation. The specific capacity of BWO/C could maintain at 436.1 mAh·g−1 after 200 cycles, which is much better than that of pure BWO (Bi2WO6). The passable reasons for BWO/C to behave outstanding electrochemical properties were discussed in our paper. The BWO/C is a promising anode material for future application. [ABSTRACT FROM AUTHOR]

Potassium-ion battery (PIB) is a potential candidate for future large-scale energy storage devices. Constructing electrode materials with fast ions and electron transport channels is an effective solution to achieve high-power-density and long-cycle PIBs. Herein, the composite composed of FeS quantum dots and nitrogen-doped porous carbon (FeS@NPC) is reported as anode material for PIBs. The unique uniform nanostructure is confirmed to be able to reduce the ion diffusion length, increase the migration rate of potassium ions, improve electronic conductivity, and alleviate volume fluctuation. These advantages deliver enhanced potassium storage properties with high capacity and excellent cycling stability. FeS@NPC-based anode obtains a specific capacity of 224 mAh g−1 at 1 A g−1 and 180 mAh g−1 at 5 A g−1 even after 1200 cycles. [ABSTRACT FROM AUTHOR]

A novel set of CuO/PPy nanocomposites (NCs) with varying PPy weight ratios was synthesized via microwave irradiation and oxidative chemical polymerization. The resulting NCs and CuO micro-flowers were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetric analysis, Brunauer–Emmett–Teller analysis, field-emission scanning electron microscopy, energy-dispersive X-ray spectroscopy line, and dot mapping techniques. The formation mechanism of CuO micro-flowers and PPy nanowires were discussed in detail. The electrochemical lithium-ion storage properties of all samples, used as anode materials in Li-ion batteries, were measured. Our results indicate that PPy nanowires with various weight ratios play a critical role in the lithium storage properties of the hybrid CuO/PPy NCs. An increase in the nanowire mass ratio enhances the cyclic durability and charge/discharge capacities of the PPy/CuO NCs. Specifically, NCs containing 3.5-, 5-, 6.2-, and 8.8-wt% PPy nanowires exhibit reversible capacities of 128, 231, 371, and 200 mAh g−1, respectively. The superior performance of the hybrid CuO/PPy NCs is attributed to the PPy nanowires. The CuO/PPy NCs benefit from the nanowire morphology and composite structural features that can accommodate the dramatic volume expansion of CuO during discharge/charge steps and enhance electrical conductivity. Our study demonstrates that tuning the PPy nanowire mass ratio in hybrid Metal Oxide/Polymer NCs is an effective method to enhance the electrode performance of an energy storage device. [ABSTRACT FROM AUTHOR]

The heterostructured arrangement of metal sulfide/oxide is of paramount importance in dictating the electrochemical characteristics of anode materials for lithium-ion batteries (LIBs). In this investigation, a synthesized composite material, integrating molybdenum disulfide (MoS2) and molybdenum dioxide (MoO2) intercalated within polyaniline (PANI) under hydrothermal conditions, was employed. Within the granulated MoO2-MoS2@PANI composite, PANI acts as an efficacious matrix, effectively mitigating the re-agglomeration and pulverization of MoS2-MoO2 during prolonged cycling processes. Concomitantly, the cooperative effects among the MoS2, MoO2, and PANI constituents manifest in copious active sites and shortened ion transport pathways. As an anode material for LIBs, the MoO2-MoS2@PANI sample exhibits exemplary cycling performance, delivering a remarkable capacity of 860 mAh g−1 even after enduring 500 cycles at a rate of 0.1 A g−1. Furthermore, when scrutinized in a sodium-ion battery (LIB) at a rate of 2 A g−1, it demonstrates exceptional cycling performance, retaining a capacity of 490 mAh g−1 even after 1000 cycles. [ABSTRACT FROM AUTHOR]

Biomass-derived carbon materials for lithium-ion batteries emerge as one of the most promising anodes from sustainable perspective. However, improving the reversible capacity and cycling performance remains a long-standing challenge. By combining the benefits of K2CO3 activation and KMnO4 hydrothermal treatment, this work proposes a two-step activation method to load MnO2 charge transfer onto biomass-derived carbon (KAC@MnO2). Comprehensive analysis reveals that KAC@MnO2 has a micro-mesoporous coexistence structure and uniform surface distribution of MnO2, thus providing an improved electrochemical performance. Specifically, KAC@MnO2 exhibits an initial charge-discharge capacity of 847.3/1813.2 mAh·g−1 at 0.2 A·g−1, which is significantly higher than that of direct pyrolysis carbon and K2CO3 activated carbon, respectively. Furthermore, the KAC@MnO2 maintains a reversible capacity of 652.6 mAh·g−1 after 100 cycles. Even at a high current density of 1.0 A·g−1, KAC@MnO2 still exhibits excellent long-term cycling stability and maintains a stable reversible capacity of 306.7 mAh·g−1 after 500 cycles. Compared with reported biochar anode materials, the KAC@MnO2 prepared in this work shows superior reversible capacity and cycling performance. Additionally, the Li+ insertion and de-insertion mechanisms are verified by ex situ X-ray diffraction analysis during the chargedischarge process, helping us better understand the energy storage mechanism of KAC@MnO2. [ABSTRACT FROM AUTHOR]

Niobium-based oxides (NMO) have attracted widespread research enthusiasm in the field of energy storage systems, including lithium-ion batteries (LIBs). Most recently, MoNb12O33 was reported as a promising material for LIBs due to its long-term cyclability, high theoretical/practical capacities, safe operating potential, and excellent structural stability. Nevertheless, the kinetics of electrochemical reactions in MoNb12O33 is hindered by its intrinsically poor electronic conductivity and electron transfer properties. These tend to be significant flaws restricting its practical use in LIBs. In this study, we employed an electrospinning technique and subsequent hydrogenation treatment for fabricating NMO and NMO@H-Ar (@H-Ar denotes heat treatment under hydrogen and argon mixture) nanowires. The hydrogenation treatment narrows the band gap, expands unit cell volume, and creates oxygen vacancies in NMO@H-Ar. These resulted in outstanding electrochemical kinetics in the NMO@H-Ar anode, including a high reversible specific capacity of 327 mAh g−1 at 0.1 C, high initial coulombic efficiency of 92.4%, excellent long-term cycling stability with capacity retention of 94.4% (capacity loss per cycle of 0.0056%) after 1000 cycles at 10 C, and good rate performance of 179.7 mAh g−1 at 10 C. In addition, the data obtained from the electrochemical impedance and cyclic voltammetry tests confirm that the hydrogenation treatment significantly enhanced the electronic conductivity and lithium-ion diffusion coefficient. This study affirms that the hydrogenation treatment considerably improved the electronic conductivity and electrochemical reactions kinetics of NMO@H-Ar nanowires, which is beneficial for developing new anode materials for LIBs. [ABSTRACT FROM AUTHOR]

MoS2 can be used as an excellent electrode material for lithium-ion batteries. However, the electrochemical performance of MoS2 is not ideal due to its large volume changes during electrochemical processes, leading to its poor cyclic stability. Here, we report a simple and reliable hydrothermal carbonization method to prepare high-performance energy storage materials. Herein, using wheat straw as a carbon source and ammonium iron sulfate hexahydrate (AFSH) as a regulator, porous wheat straw carbon (PWSC) materials were prepared by hydrothermal and high-temperature carbonization treatment. Using the obtained porous carbon as a carbon matrix, a triblock copolymer F127 was selected to control the morphology of MoS2, and a porous wheat straw carbon and flower-like MoS2 composite (PWSC@MoS2) was synthesized by hydrothermal method. The effects of the amount of structural modifier on the overall electrochemical properties of the composites were investigated. It was finally determined that the composite (PWSC@ MoS2-2) at the optimal structural modifier ratio of 1:2 showed high lithium storage capacity (1435 mAh g−1 after 100 cycles at 0.2 C), excellent cycling stability, and superior rate performance. Therefore, this efficient and environmentally friendly method of preparing PWSC@MoS2 composites from wheat straw can realize the secondary utilization of biomass waste and is a new choice of anode materials for lithium-ion batteries. [ABSTRACT FROM AUTHOR]

The scalable synthesis of MoS2/N-doped carbon (MoS2/NC) nanosheets was accomplished using a facile salt template–assisted synthesis method. The MoS2 nanosheets were uniformly encapsulated in nitrogen-doped carbon frameworks. As an anode for sodium-ion batteries (SIBs), the electrochemical performance of the MoS2/NC electrode was significantly improved compared to pure MoS2, which demonstrated a reversible capacity of 334.6 mAh g−1 after 100 cycles at 0.2 A g−1; even after 250 cycles of 1 A g−1, the capacity could still be maintained at 252.9 mAh g−1. This excellent sodium storage performance was mainly due to the coupling of nitrogen-doped carbon with MoS2 and the uniform distribution of the nanosheets, which improved the reaction kinetics. Besides, the electrochemical reconstruction ensured the integrity of the electrode. This work was of great significance for the large-scale synthesis of MoS2 anode material with enhanced stability SIBs. [ABSTRACT FROM AUTHOR]

For the high content of sp-hybridized carbon atoms, carbyne based materials can express superior conductivity and ultra-high theoretical capacity, which are key factors of high-performance anode. However, the poor stability of synthetic intermediates and unwanted side reactions lead to huge challenge to synthesis carbyne alternating carbon–carbon triple and single bonds. Here, we rationally designed a smart "Greedy Snake" strategy to synthesize the alkyne rich carbon materials named Si capped alkyne rich carbon (Si-Alkyne-C) which comprised of sp-hybridized carbon atoms. The as-prepared Si-Alkyne-C generated on the copper surface through a carbon–carbon coupling, in which Si can effectively protect the intermediates generated by the reaction. The C–Si bond can constantly generate copper-alkyne intermediates to couple with other terminal alkynes to continuously elongate like "Greedy Snake", forming a long alkyne chain structure. The as-prepared Si-Alkyne-C can be applied as anode electrodes, exhibited very high reversible capacity of up to 2776 mAh/g at a current density of 50 mA/g and an average capacity around 1202 mAh/g at a high current density of 5000 mA/g for 5000 cycles, which are the best results among the reported carbon materials and better than many other anode materials. These results not only provide a facile strategy to prepare carbyne based materials, but also open a broad avenue for the preparation of high-capacity anode materials. [ABSTRACT FROM AUTHOR]

The iron(II) phosphate-oxalate compound, namely (C4H12N2)[Fe4(HPO4)2(C2O4)3] (abbreviated as FPC), was synthesized and studied as anode material for lithium-ion batteries (LIBs). The structure of FPC was characterized by single-crystal X-ray diffraction. The FPC anode material gives a reversible capacity of 966.1 mAh g−1 after 400 cycles and good rate capability of 383.1 mAh g−1 at 2 A g−1. The lithium storage mechanism for FPC was analyzed. The results suggest that the electrochemical activity of FPC arises from the conversion reaction accompanied by the formation of Li3PO4 after lithiation. The in situ generation of ion conductive Li3PO4 and the redox process between FePO4 and Fe contribute to the good rate capability and cycling stability of the FPC anode. [ABSTRACT FROM AUTHOR]

FeWO4 and Fe1−xCoxWO4 compounds (x = 0.05, 0.1, 0.2, 0.3) were synthesized through a solvothermal method. As an anode material for lithium-ion batteries (LIBs), the Fe0.9Co0.1WO4 compound demonstrated high discharge specific capacity of 1188.6 mAh g−1 after 100 cycles at 100 mA g−1, which is much higher than that of FeWO4. Moreover, Fe0.9Co0.1WO4 exhibited the best rate performance and the best cyclic performance, as well as the lowest charge-voltage platform, among all Co-doped samples. The superior electrochemical performance of Fe0.9Co0.1WO4 was attributed to the Co doping with the appropriate amount, which led to a regular micron structure that ultimately promoted Li+ embedding and de-embedding. Furthermore, the synergistic effect of Co2+ and Fe2+ also enhanced the conductivity of the electrode material, which reduced electrode polarization during discharge and charge processes. Therefore, Fe0.9Co0.1WO4 is a promising anode material for LIB applications. [ABSTRACT FROM AUTHOR]

Nanomaterials have been used as the electrodes of lithium-ion batteries during the past years. Designing nanomaterials with a simple method is significant for lithium-ion batteries that will be applied in electric vehicles and portable electronic devices. In this study, a simple one-pot strategy was used to grow MOx (M = Co, Ni, Cu) metal oxide nanoparticles on N-doped reduced graphene oxide (rGO) sheets. The MOx/N-doped rGO composites were subsequently studied as the anodes of lithium-ion batteries. Results demonstrated that the one-pot method effectively prevents the aggregation of nanoparticles and the restacking of graphene sheets, which is important to improve the electrochemical performance of composites. Electrochemical measurements of the three composites as anode materials exhibited the high reversible capacitance, rate capability, and cyclic stability. Highlights: A simple one-pot strategy was used to grow MOx (M = Co, Ni, Cu) metal oxide nanoparticles on N-doped reduced graphene oxide (rGO) sheets. Urea was used as crosslinking agent, nitrogen source, and reducing agent of GO during the one-pot synthesis. Electrochemical performance of three composite were investigated as the anode materials of lithium-ion batteries. Anodes exhibited the high reversible capacity, excellent rate performance, and ideal cycling performance. [ABSTRACT FROM AUTHOR]

Highlights: Heterostructure engineering is proposed to construct CoTe2/ZnTe heterostructures with built-in electric field. Conductive and elastic Ti3C2Tx MXene is introduced to improve the conductivity and alleviate the volume change of CoTe2/ZnTe upon cycling. The resulting CoTe2/ZnTe/Ti3C2Tx (CZT) demonstrates outstanding rate capability (137.0 mAh g−1 at 10 A g−1) and cycling stability (175.3 mAh g−1 after 4000 cycles at 3.0 A g−1). Moreover, the CZT-based full cells demonstrate excellent energy density (220.2 Wh kg−1) and power density (837.2 W kg−1). Exploiting high-rate anode materials with fast K+ diffusion is intriguing for the development of advanced potassium-ion batteries (KIBs) but remains unrealized. Here, heterostructure engineering is proposed to construct the dual transition metal tellurides (CoTe2/ZnTe), which are anchored onto two-dimensional (2D) Ti3C2Tx MXene nanosheets. Various theoretical modeling and experimental findings reveal that heterostructure engineering can regulate the electronic structures of CoTe2/ZnTe interfaces, improving K+ diffusion and adsorption. In addition, the different work functions between CoTe2/ZnTe induce a robust built-in electric field at the CoTe2/ZnTe interface, providing a strong driving force to facilitate charge transport. Moreover, the conductive and elastic Ti3C2Tx can effectively promote electrode conductivity and alleviate the volume change of CoTe2/ZnTe heterostructures upon cycling. Owing to these merits, the resulting CoTe2/ZnTe/Ti3C2Tx (CZT) exhibit excellent rate capability (137.0 mAh g−1 at 10 A g−1) and cycling stability (175.3 mAh g−1 after 4000 cycles at 3.0 A g−1, with a high capacity retention of 89.4%). More impressively, the CZT-based full cells demonstrate high energy density (220.2 Wh kg−1) and power density (837.2 W kg−1). This work provides a general and effective strategy by integrating heterostructure engineering and 2D material nanocompositing for designing advanced high-rate anode materials for next-generation KIBs. [ABSTRACT FROM AUTHOR]

The high energy density of Si makes it a preferred anode material for lithium-ion batteries. However, the low conductivity and large volume changes associated with the charging and discharging processes lead to a rapid decay in capacity during cycling, which hinders its commercialization. In this study, micron-scale PSi@PEDOT/GO composites were prepared by coating commercial Al–Si alloys with poly 3,4-ethylenedioxythiophene (PEDOT) and graphene oxide (GO) using in situ polymerization and freeze-drying methods. The core layer of the PSi@PEDOT/GO composite has abundant internal pores to provide sufficient space to adapt to the volume change of silicon, whereas the PEDOT and GO coating layers can accelerate the ion and electron transport and accommodate the volume change of silicon, which can effectively improve the cycling stability and rate performance of the silicon anode. The characterization results show that the PSi@PEDOT/GO-2 (mass ratio = 6:4:5) composite electrode material has a specific capacity of 1102.30 mAh/g after 110 cycles. When the current density is 0.3A/g, the specific capacity is still 1102.30 mAh/g after 110 cycles, and the capacity retention rate is 75.8%. In addition, it exhibits a specific capacity of 406.87 mAh/g at a current density of 4 A/g, indicating excellent cycling and rate performance and good application prospects. [ABSTRACT FROM AUTHOR]

The world's energy supply depends heavily on lithium-ion batteries due to the progressive depletion of non-renewable resources. The issue of raising the energy density of lithium-ion batteries must be addressed. We are all aware that the anode material is one area where lithium-ion batteries still have room for development. A new anode material, tin disulfide, not only has a high theoretical specific capacity (645 mAh g−1), but also allows the formation of different microstructures through variable growth rates. In this study, we created three-dimensional nano-spheres of SnS2 using solid-phase synthesis and then wrapped SnS2 and B4C in OUCNTs (SnS2/B4C@OUCNT) using hydrothermal synthesis. Ascribed to the synergy between the highly chemical active B4C and the conductive carbon network of the OUCNTs, SnS2/B4C@OUCNT (149 Ω) effectively overcomes the drawback of high impedance of pure SnS2 (307 Ω) while exhibiting high capacity and cyclic stability. After 100 cycles at a current density of 100 mA g−1, this material displayed good electrochemical properties as the anode for lithium-ion batteries, obtaining a reversible capacity of 1024.7 mAh g−1 and a coulombic efficiency of 98.01%. The discharge capacity is 854.7 mAh g−1 with a coulombic efficiency of 98.57% after 200 cycles at 1000 mA g−1. [ABSTRACT FROM AUTHOR]

Various transition metal dichalcogenides materials have been investigated from bulk to monolayer phases for different advanced technological applications. Tin disulfide monolayer offers advantages as an anode material for Li/Na-ion batteries, although it cannot be considered ideal for direct exploitation. We systematically performed a comparative study of the adsorption and diffusion behaviour of Li/Na on a pristine SnS 2 monolayer and on a SnS 2 monolayer with S-vacancy for enhancement of electrochemical performance, using density functional theory approach. Although all the adsorption sites are exothermic, it was established that Li/Na adatoms mostly prefer to bind strongly on SnS 2 monolayer with S-vacancy but avoiding the S-vacancy site. It was established that avoiding the S-vacancy site along the path, excellent diffusion barriers of 0.19 eV for Li and 0.13 eV for Na were achieved, suggesting possible ultrafast charge/discharge rate. Due to reduced molar mass, the SnS 2 monolayer with S-vacancy has a slightly higher storage capacity than its pristine counterparts for both Li and Na adatoms. The obtained open circuit voltage values are within the range of 0.25–3.00 V assuring that the formation of dendrites can surely be averted for the envisaged battery operation. Understanding the effects of an S-vacancy on the electrochemical properties of Li/Na on the SnS 2 monolayer allows us to consider possible improvements to energy storage devices that can be applied as a result of improved anode material. [ABSTRACT FROM AUTHOR]

Zn3V3O8 was successfully synthesized by mix solvothermal method. The NH4F was used as an additive (agent) to control morphology of Zn3V3O8. It was found that suitable percentage concentration of NH4F could control morphology of Zn3V3O8 as two-dimensional (2D) sheets. The X-ray diffraction (XRD) and field emission scanning electron microscopy (SEM) were used to characterize the structure and morphology of the samples, and the battery comprehensive testing system was used to study its electrochemical properties. The results showed that the Zn3V3O8 was successfully obtained by mix solvothermal method (water: ethylene glycol = 1:1), and 2D Zn3V3O8 sheets was synthesized by adding NH4F as soft template. The initial discharge capacity for 2D Zn3V3O8 micro sheets is 1709.6 mAh·g−1 at 100 mA/g in the voltage range of 0.01–3 V. After 100 cycles, it could maintain at 1372 mAh·g−1. The Zn3V3O8 two-dimensional micro sheets behaved good rate performances also. So Zn3V3O8 two-dimensional micro sheets synthesized by this way is a novel and promising anode material for lithium ion battery application. [ABSTRACT FROM AUTHOR]

Hard carbon (HC), composed of disorder graphite domain construction, provides defects, gaps, and nanopores that are beneficial for storing K-ion. In this work, hard carbon derived from spent black tea (THC) is synthesized through a two-step carbonization process. THC is an easy preparation, green, and high-abundance carbon material for highly stable potassium-ion storage. As an anode for potassium-ion batteries, it delivers a high capacity of 203 mA h g−1 at 30 mA g−1 and long-term cycling life with 90% capacity retention over 3.6 months. This superior cycle life is attributed to the highly reversible structure, rapid ion diffusion rate, and charge transfer rate of THC. Not only that, a full cell was assembled with THC as the anode and perylene 3,4,9,10-tetracarboxylic dianhydride (PTCDA) as the cathode. The PTCDA//THC delivers a high capacity of 48.6 mA h g−1 and an energy density of 107 W h kg−1 at 100 mA g−1. These findings suggest that THC has considerable promise as a low-cost, high-stability anode material for potassium-ion batteries. [ABSTRACT FROM AUTHOR]

In order to solve the problem of poor conductivity and expansion of ferric oxide (Fe3O4), firstly, the composite powder of carbon nanotubes (CNTs) and nanoFe3O4 was prepared, then CNT/Fe3O4 encapsulated by pitch (Fe3O4/CNT@pitch) powder were obtained by solution coating, and further carbonization to obtain CNT/Fe3O4@C nanocomposites. Our results indicate that CNT content in the CNT/Fe3O4@C has significant effect on the electrochemical performance. CNT/Fe3O4@C with high (5.88wt%) content of CNT (CNT-M/Fe3O4@C) has more excellent rate characteristics, which is due to its low charge transfer resistance and high conductivity, while CNT/Fe3O4@C with low (0.31wt%) content of CNT (CNT-S/Fe3O4@C) exhibits the highest reversible specific capacity of 588.8 mAh g−1 when compared with 425.6 mAh g−1 for CNT-M/Fe3O4@C after 300 cycles at 100 mA g−1, which is due to its low specific surface area. The simple preparation process of CNT/Fe3O4@C is worth industrialization. [ABSTRACT FROM AUTHOR]

Silicon nanowires (NWs) have been attracting attention as an anode material for the high-performance lithium-ion batteries (LIBs) despite its large volume expansion over 400% when charging that causes early material failure or degradation due to high contact stresses between particles. In order to solve such problems, a numerical method is proposed to find the optimum arrangements and dimensions of NWs at an anode. As a result of multi-physical analyses on the cylindrical and spherical silicon particles, it is found that the cylinder type is more suitable. The two dimensional (2D) topology optimization method based on the level-set algorithm, Li-ion transportation, changing Si NW properties with the state of charge, and finite element method is formulated and coded numerically for the first time. After the level-set topology optimization, the optimum radius and arrangement of cylindrical Si NWs at the anode that do not cause excessive contact stresses among NWs without compromising the performance and durability of LIBs. Finally, the detailed finite element analyses are done on the optimum dimensions of NWs to confirm that the stress and strain are within the specified limits. [ABSTRACT FROM AUTHOR]

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Mn3O4 nano-octahedrons embedded in N-doped graphene oxide (MNGO) nanosheets were synthesized using a simple, energy-efficient, and rapid microwave-digested hydrothermal route in a single step. The structural and morphological aspects of synthesized materials were evaluated by XRD, IR, Raman, FE-SEM, and HR-TEM techniques. Then, the composite MNGO was tested for its Li-ion storage properties and compared with reduced graphene oxide (rGO) and Mn3O4 materials. The MNGO composite exhibited superior reversible specific capacity, excellent cyclic stability, and outstanding structural integrity throughout the electrochemical studies. The MNGO composite showed a reversible capacity of 898 mA h g−1 after 100 cycles at 100 mA g−1 and Coulombic efficiency of 97.8%. Even at a higher current density of 500 mA g−1, it exhibits a higher specific capacity of 532 mA h g−1 (~1.5 times higher than commercial graphite anode). These results demonstrate that Mn3O4 nano-octahedrons embedded on N-doped GO are a highly durable and potent anode material for LIBs. [ABSTRACT FROM AUTHOR]

The copper hydroxyphosphate Cu2(OH)PO4 was synthesized under mild hydrothermal conditions and structurally characterized by single-crystal X-ray diffraction. The electrochemical performance of Cu2(OH)PO4 as anode material for lithium-ion batteries (LIBs) was investigated. The Cu2(OH)PO4 anode delivers a capacity of 741.1 mAh g−1 at 0.1 A g−1 over 300 cycles. The electrochemical and structural analyses suggest that the Cu2(OH)PO4 anode undergoes the conversion reaction with Li+ ions during lithium storage process. The in situ generated ion conductive Li3PO4 is much beneficial to enhance Li+ diffusion that leads to good rate capability and cycling stability. Besides the diffusion-controlled process, the surface capacitive effect also considerably contributes to the achieved capacity of the electrode. The results indicate that the polyanionic metal phosphate compounds are potential candidates for conversion-type anode materials for LIBs. [ABSTRACT FROM AUTHOR]

Tin-based materials are very attractive anodes because of their high theoretical capacity, but their rapid capacity fading from volume expansions limits their practical applications during alloying and dealloying processes. Herein, the improved binder-free tin-copper intermetallic/carbon nanotubes (Cu6Sn5/CNTs) alloy thin-film electrodes are directly fabricated through efficient in situ electrodeposition from the leaching solution of treated waste-printed circuit boards (WPCBs). The characterization results show that the easily agglomerated Cu6Sn5 alloy nanoparticles are uniformly dispersed across the three-dimensional network when the CNTs concentration in the electrodeposition solution is maintained at 0.2 g·L−1. Moreover, the optimal Cu6Sn5/CNTs-0.2 alloy thin-film electrode can not only provide a decent discharge specific capacity of 458.35 mAh·g−1 after 50 cycles at 100 mA·g−1 within capacity retention of 82.58% but also deliver a relatively high reversible specific capacity of 518.24, 445.52, 418.18, 345.33, and 278.05 mAh·g−1 at step-increased current density of 0.1, 0.2, 0.5, 1.0, and 2.0 A·g−1, respectively. Therefore, the preparation process of the Cu6Sn5/CNTs-0.2 alloy thin-film electrode with improved electrochemical performance may provide a cost-effective strategy for the resource utilization of WPCBs to fabricate anode materials for lithium-ion batteries. [ABSTRACT FROM AUTHOR]

The carbon-coated ZnO nanospheres materials have been synthesized via a simple hydrothermal method. The effect of carbon content on the microstructure, morphology and electrochemical performance of the materials was investigated by XRD, Raman spectroscopy, transmission electron microscopy, scanning electron microscopy and electrochemical techniques. Research results show that the spherical ZnO/C material with a carbon cladding content of 10% is very homogeneous and approximately 200 nm in size. The electrochemical performances of the ZnO/C nanospheres as an anode materials are examines. The ZnO/C exhibits better stability than pure ZnO, excellent lithium storage properties as well as improved circulation performance. The Coulomb efficiency of the ZnO/C with 10% carbon coated content reaches 98%. The improvement of electrochemical performance can be attributed to the carbon layer on the ZnO surface. The large volume change of ZnO during the charge-discharge process can be effectively relieved. [ABSTRACT FROM AUTHOR]

The Si-based flexible electrodes attracted increasing research interests owing to the growing demand for high-performance flexible energy storage devices. Herein, a facile and smart self-assembly strategy is adopted to address huge volume expansion and particle aggregation issues of Si-based anodes, and a high-performance freestanding film anode (NC@Si/CNTs/N-rGO) is synthesized. The 3D-crosslinked porous graphene-CNTs networks offer abundant electric conductive pathways, high active sites, large internal space to accommodate the expansion of Si NPs, and facilitate Li+ diffusion and insertion/extraction kinetics. The synergistic effect between the well-dispersed Si/NC nanoparticles and 3D porous networks significantly enhances electrochemical performance of Si NPs. The as-prepared NC@Si/CNTs/N-rGO electrode exhibits a high reversible specific capacity of 1089 mAh·g−1 at a charge–discharge current density of 1 A·g−1 after 500 cycles. Even at 2 A·g−1, the electrode still exhibits an excellent reversible specific capacity of 606 mAh·g−1 after 300 cycles. These indicate that the NC@Si/CNTs/N-rGO is a promising candidate for high-performance flexible anode material in lithium-ion batteries. [ABSTRACT FROM AUTHOR]

Nickel cobalt layered double hydroxide (NiCo-LDH) nanosheets have attracted much interests in lithium-ion batteries (LIBs) because of its high capacity and low cost. However, the low cycling stability limits their practical applications. Herein, we introduce a simple one-pot hydrothermal method to fabricate a novel flower-shaped Zif-67@NiCo-LDH heterostructure as the anode materials. The structures, morphology, and compositions of the materials were studied by XRD, SEM, TEM, XPS, EDX, and Raman spectra. Electrochemical tests were also conducted. The Zif-67@NiCo-LDH simultaneously inherited the cycling stability of Zif-67 and the high capacity of NiCo-LDH, which effectively improves the conductivity and structural integrity under the synergistic effect of the flower-shaped heterostructures and compositions and showed a good electrochemical performance. This work might enable the future design of heterostructures materials with layered double hydroxide for many other energy-storage technologies. [ABSTRACT FROM AUTHOR]

Despite the high theoretical capacity of iron-based anode materials, they still perform poorly in electrical conductivity and volume expansion during the charge/discharge process, which can reduce battery life and cause deterioration in cycle performance. In the present study, iron-based metal–organic frameworks are synthesized through a simple co-precipitation method, and then heat-treated as a self-sacrificing template to obtain carbon-coated Fe3O4 of a porous ortho-octahedral structure. As revealed by electrochemical performance studies, this material maintains a high specific capacity, showing a reversible capacity of 1063 mAh/g and 896 mAh/g after 300 cycles at a current density of 0.5 A/g and 1 A/g. By analyzing the functional mechanism of surface carbon coating, it is demonstrated that the fast ion migration and high electrical conductivity required for fast charging and discharging are ensured by the octahedral and hierarchical void structure of the carbon framework. This study thus provides a reference for the design of high-performance electrode materials. [ABSTRACT FROM AUTHOR]

The preparation of CuCo2O4 material with a suitable phase structure and grain size can improve its lithium storage performance. In this paper, CuCo2O4 hexagonal nanocrystal were successfully obtained by molten salt modified urea combustion method. Compared with the traditional high temperature solid state methods such as combustion method, rheological phase method and precipitation method, this method maintains the advantage of simple operation, and the particle size of the sample is smaller. The effect of heat treatment temperature on the lithium storage performance of CuCo2O4 was also studied systematically in this paper. The result shows that 800 ℃ is the best heat treatment temperature for CuCo2O4, and the sample synthesized by the molten salt urea combustion method exhibited the best electrochemical properties with a specific capacity of 705 mA h g-1 after 100 cycles under a constant current of 200 mA g-1 in the voltage range of 0.01-3 V. Therefore, a new strategy of high temperature solid state preparation has been developed in this paper, and the CuCo2O4 synthesized by this method is a promising anode material for lithium ion battery application. [ABSTRACT FROM AUTHOR]

Oily sewage discharged from ships has brought many harms to the marine environment, even endangered marine life and human life. As a new type of water treatment technology, microbial fuel cell (MFC) can efficiently treat pollutants and recover energy, which can be converted into electric energy. However, its large internal resistance restricts its development. In order to solve the problems of low power generation performance and poor biocompatibility of microbial fuel cell, a gold nanoparticle-carbon quantum dot/polydopamine/graphene oxide/bacterial cellulose (AuNP-CQD/PDA/GO/BC) electrode was prepared, and it was applied to the treatment of oily sewage from ships. Fourier transforms infrared spectroscopy, X-ray diffraction, scanning electron microscopy, gas chromatography-mass spectrometry, and contact angle measuring instrument were used to characterize the electrode. The results show that PDA bridges GO and AuNP-CQD particles through the electrostatic interaction/π-π bond/hydrogen bonding, respectively. This attracts a large number of microorganisms to attach to the surface of the porous anode material, which greatly improves the activity and quantity of microorganisms. Moreover, the maximum power density of AuNP-CQD/PDA/GO/BC electrode is 2624.91 mW/m2, which obviously improves the electrochemical performance of MFC. The oil content of the treated water is ≤ 15 mg/L, reaching the discharge of MARPOL 73/78 convention. Therefore, the proposed approach has paved new dimensions in not only the preparation of a new composite electrode materials but also its applications as effective degradation of ship oily sewage in MFC. [ABSTRACT FROM AUTHOR]

Among all rechargeable secondary batteries, lithium-ion batteries (LIBs) are the most important breakthrough in the field of energy storage. In this paper, we successfully construct octahedral Fe2P/C composite nanoparticles anchored on reduced graphene oxide (Fe2P/C@rGO) nanocomposites as LIB anodes, used the synthesized octahedron Fe-metal–organic frameworks and graphene oxide composite (Fe-MOF@GO) as the precursor and NaH2PO2 as phosphorus source via high-temperature calcination. Under a current density of 0.1 A g−1, the reversible capacity of octahedral Fe2P/C@rGO is 983.1 mAh g−1 after 180 cycles. Its long-cycle performance is very good, its reversible capacity can still be kept at 733.3 mAh g−1 at 1.0 A g−1 after 500 cycles. Such excellent capacity is attributed to this unique three-dimensional octahedral structure. At the same time, the doping of P element and the addition of rGO also play an important role. [ABSTRACT FROM AUTHOR]

In this work, the SiO2@Fe2O3 nanocomposite using SiO2-derived from the laboratory glass waste and commercial Fe2O3 was generated by means of ball milling technique. The phase formation, chemical composition and morphology of the prepared SiO2@Fe2O3 nanocomposite were confirmed using various material characterization techniques such as X-ray diffraction, Raman spectroscopy, Fourier-transformed infrared spectroscopy and field-emission scanning electron microscopy. The lithium-ion battery half-cell and full-cell performances of the SiO2@Fe2O3 nanocomposite anode were examined in CR-2032 coin cell. The half-cell had nanostructured SiO2@Fe2O3 as anode and lithium metal as counter electrode, whilst the full-cell was fabricated using LiCoO2 as cathode. The fabricated coin cell was subjected to electrochemical studies viz, cyclic voltammetry, galvanostatic charge–discharge and electrochemical impedance spectroscopy. The SiO2@Fe2O3 anode exhibited half-cell capacity of 530 mAh g−1 at 0.2C-rate, with almost stable rate performance as well as cycling stability. The high discharge capacity was attributed to the simultaneous occurrence of conversion/re-conversion by the Fe2O3 and alloying/dealloying by the SiO2. The Fe2O3 acted as buffer to accommodate the volume change associated with the lithiated phase Li4.4Si. The lithium-ion full-cell battery exhibited a high discharge capacity of 780 mAh g−1 at 0.1C-rate with excellent coulombic efficiency and stability over 500 charge–discharge cycles at 0.8C-rate. [ABSTRACT FROM AUTHOR]

Silicon/carbon composites have been considered as the anode material of choice for improving the energy density of lithium-ion batteries (LIBs). The carbon-based matrices not only can provide a conductive network for Si, but can also mitigate the bulk expansion of Si. However, the Si/C anode also has obvious disadvantages, such as a complicated preparation process and unstable solid–electrolyte interface (SEI) film, which leads to low initial coulombic efficiency and poor cycle life. In this study, ferrocene was successfully used as the sole source of Fe3O4 and carbon to prepare a core–shell structured Si@Fe3O4@C composite by wrapping a Fe3O4@C layer on the Si surface under hydrothermal action. The synthesized Si@Fe3O4@C composite exhibits excellent cycling stability (1026 mA h g−1 after 500 cycles at 1 A g−1) and rate performance (744 mA h g−1 at 4 A g−1). The good electrochemical performance can be ascribed to Fe3O4 nanoparticles embedded into the carbon layer, which effectively improves the electronic conductivity and interfacial stability of Si@C anode materials. [ABSTRACT FROM AUTHOR]

Herein, a method for the preparation of hard carbon via carbonization of chemically modified (molybdenum-doped) commercially available viscose fiber was developed. The effects of a molybdenum dopant on carbonization conditions were studied. The carbonization products retained the fibrous structure and flexibility. The structural features of the synthesized hard carbon materials were investigated, and their relationships to the carbonization temperature and the amount of the molybdenum dopant were analyzed. The texture of materials was studied, and correlations between the specific surface area and porosity, on the one hand, and the synthesis conditions, on the other, were discovered. The usefulness of the products as anode materials for sodium-ion batteries was evaluated. The electrochemical tests, together the extant relevant data, indicate that molybdenum induces the structural rearrangement of the carbon framework upon annealing, accompanied by the growth and ordering of graphite-like nanoclusters. The material prepared at 1050°C exhibited the best electrochemical performances among the synthesized products and the stable cyclability with a capacity of 290 (mA h)/g at a current density of 25 mA/g. [ABSTRACT FROM AUTHOR]