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Organic polymers have been considered reliable candidates for lithium storage due to their high capacity and lack of volume expansion. Compared with other organic polymers, polyimide has become a very promising electrode material for lithium‐ion batteries (LIBs) because of its easy synthesis, customizable structure and structural stability. A large number of studies have confirmed that the benzene ring structure of polyimide has strong lithium storage capacity as an anode material. Hence, we designed and synthesized polyimide organic polymer (PBPAQ) for the first time. The unique spherical flower structure of this material enhances the interaction between the electrode material and the electrolyte by increasing the contact area. The PBPAQ anode has a specific discharge capacity of 738 mAh g−1 after 100 cycles at 0.1 A g−1. The excellent lithium storage performance of this material laid a foundation for the research of the anode of LIBs in the future. [ABSTRACT FROM AUTHOR]

Sodium‐ion hybrid capacitors (SIHCs) are considered a prospective alternative to lithium‐ion batteries (LIBs) since there are rich and available sodium reserves. Here, nitrogen‐doped carbon tubes (N‐MJ) derived from metaplexis japonica fluff are prepared by using a facile method of etching and peeling the fluff with urea to prepare a Na+ storage anode. With prominent traits in terms of structure and a high nitrogen content (11.08 %), N‐MJ exhibits exceptional Na+ storage performance with a high reversible capacity (390.9 mAh g−1 at 50 mA g−1) and excellent long‐term circulation (208.1 mAh g−1 after 2650 cycles at 1 A g−1). Systemic kinetic analysis manifests that the extraordinary performance is responsible for the large‐scale capacitance control. Furthermore, the SIHCs assembled by using N‐MJ and activated carbon (AC) presents a maximum energy density of 111.4 Wh kg−1 (at 445.8 W kg−1) and power density of 2455.2 W kg−1 (at 34.1 Wh kg−1). Notably, the developed SIHCs maintain a 100 % capacity retention rate at 1 A g−1 after 5000 cycles. Overall, our work not only provides a good choice for storage Na+ anode materials, but also supplies a feasible method for the recycling of waste biomass. [ABSTRACT FROM AUTHOR]

Abstract: The electrochemical performances of magnesium, magnesium–lithium–aluminum–cerium and magnesium–lithium–aluminum–cerium–yttrium as the anode of magnesium–hydrogen peroxide semi-fuel cells have been studied by methods of potentiodynamic, potentiostatic and electrochemical impedence measurements. The surface morphologies of magnesium and its alloys have been examined by scanning electron microscopy (SEM). It has been found that magnesium–lithium–aluminum–cerium and magnesium–lithium–aluminum–cerium–yttrium electrodes are less corrosion resistant than that of magnesium electrode in 0.7molL−1 NaCl solution and the corrosion current density decreases with the following order: magnesium

[Display omitted] MoS 2 is regarded as an attractive anode material for lithium-ion batteries due to its layered structure and high theoretical specific capacity. Its unsatisfied conductivity and the considerable volume change during the charge and discharge process, however, limits its rate performance and cycling stability. Herein, 3D tremella-like nitrogen-doped carbon encapsulated few-layer MoS 2 (MoS 2 @NC) hybrid is obtained via a unique strategy with simultaneously poly-dopamine carbonization, and molybdenum oxide specifies sulfurization. The three-dimensional porous nitrogen-doped carbon served both as a mechanical supporting structure for stabilization of few-layers MoS 2 and a good electron conductor. The MoS 2 @NC exhibits enhanced high rate performance with a specific capacity of 208.7 mAh g−1 at a current density of 10 A g−1 and stable cycling performance with a capacity retention rate of 85.7% after 1000 cycles at 2 A g−1. [ABSTRACT FROM AUTHOR]

A three-dimensional free-standing hard carbon (FHC) electrode is synthesized by carbonizing the hemp haulm and employed as anode for sodium-ion batteries directly. A high current charging-discharging process is carried out to reconstruct surface structure of the FHC. Surface reconstructed FHC display a high capacity of 256 mAh/g and enhanced rate ability. With the formation of order surface structure, the plateau capacity increase and more sodium ions can insert into the FHC. This work demonstrates the importance of surface structure for sodium ion diffusion and storage and provide a new strategy to design high-performance anode materials. [ABSTRACT FROM AUTHOR]

Architecture of electrode materials plays an important role in achieving favorable electrochemical performance via providing fast electronic transport pathway and shorten lithium ion diffusion distance. Herein, ultrafine CoP nanoparticles were successfully embedded in carbon nanorod, which were grown on the biomass-derived carbon (BC). When applied as anode materials for lithium-ion batteries, these CoP@C/BC displayed capable specific capacity, remarkable rate ability and outstanding long-term cycling performance. The capacity was governed by combination of diffusion-controlled and capacitive processes, according to quantitative kinetic analysis. The good electrochemical performance is attributed to hierarchical construction of nanosized CoP embedded in carbon nanorod and BC with high conductivity composite, which relieve the volume changing of CoP and provide large electrode/electrolyte interface. The present design of hierarchical architecture can be extended to other transition metal-based oxides, sulfide and phosphide electrode materials for high performance alkali metal ion batteries. [ABSTRACT FROM AUTHOR]

Porous Ni 2 P nanoflower supported on nickel foam (Ni 2 P@Ni foam) electrodes are synthesized via a simple hydrothermal growth strategy accompanied with further phosphating treatment. The prepared electrodes are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and transmission electron microscopy (TEM). Electro-catalytic performances towards urea electro-oxidation are tested by cyclic voltammetry (CV), chronoamperometry (CA) coupled with electrochemical impedance spectroscopy (EIS). By phosphating Ni(OH) 2 precursor, the final obtained Ni 2 P@Ni foam electrode presents a porous Ni 2 P nanoflower structure within abundant porosity, and so exposes a large amount of electro-catalytic active sites and electronic transmission channels to accelerate the interfacial reaction. Compared with Ni(OH) 2 @Ni foam precursor, the Ni 2 P@Ni foam catalyst exhibits more excellent electro-catalytic activity as well as lower onset oxidation potential. Remarkably, the Ni 2 P@Ni foam catalyst reaches a peak current density of 750 mA cm −2 with an onset oxidation potential of 0.24 V (vs. Ag/AgCl) accompanied by an excellent stability in 0.60 M urea with 5.00 M KOH solutions. Benefiting from the unique porous nanosheet structure, the as-synthesized Ni 2 P@Ni foam catalyst performs a highly enhanced catalytic behavior for alkaline urea electro-oxidation, indicating that the material can be hopefully applied in direct urea fuel cells. [ABSTRACT FROM AUTHOR]

Novel Au@Ni nanoarrays electrode is facilely obtained by firstly template-assisted electro-deposition of Ni nanowire arrays (NAs), followed by galvanostatic deposition of Au catalysts onto the Ni NAs without any conductive agents and binders. The Au@Ni NAs electrode shows a rough surface and fringe with the diameter of ∼90 nm, which assures a high utilization of Au catalysts and provides a large specific surface area. The elemental distribution of Ni mainly exists in the inner layer of a single Au@Ni nanowire with the diameter ∼56 nm, while the elemental distribution of Au catalysts merely appears in the outer layer to form the unique core-shell nanowire structure. The Au@Ni NAs electrode reveals excellent electrochemical property and desirable stability for catalyzing NaBH 4 electro-oxidation in basic solutions. The Au@Ni NAs electrode in the 2.00 M NaOH and 0.24 M NaBH 4 solution demonstrates an oxidation current density of 2.35 A mg −1 at −0.5 V (vs. Ag/AgCl), which is much higher than that of the noble metal catalysts previously reported, indicating that this material may be hopefully used as anodic catalysts for applying in fuel cells. [ABSTRACT FROM AUTHOR]

Thorn-like Ni@TiC NAs and flake-like Co@TiC NAs electrodes without any conductive agent and binder are simply fabricated by the potentiostatic electrodeposition of Ni and Co catalysts on the TiC nanowire arrays (NAs). The electrocatalytic activity of H 2 O 2 oxidation on the Ni@TiC NAs electrodes is better than that on the Co@TiC NAs electrodes. The Ni@TiC NAs electrodes demonstrate a rough surface and have many nano-needles on the rod edges, which assures the high utilized efficiency of Ni catalysts. These particular three-dimensional structures may be very suitable for H 2 O 2 electrooxidation. The anodic current of Ni@TiC NAs anode reaches 0.32 A cm −2 at 0.3 V in 1.0 M H 2 O 2 + 4 M KOH solution. The DPFCs employing Ni@TiC NAs anodes display the peak power density of 30.2 mW cm −2 and open circuit voltage of 0.90 V at 85.1 mA cm −2 with desirable cell stability at 10 mL min −1 flow rate and 20 °C, which is much higher than those previously reported. [ABSTRACT FROM AUTHOR]

Organic polymer materials attract lots of attention as promising anode materials for lithium ion batteries (LIBs) due to the superior lithium ion storage capability and low cost. However, the inherent insulativity of the polymer anodes results in the unsatisfactory electrochemical performance. Herein, we design and construct a hierarchical flowers-like polyaniline-coated (PANI) pyromellitic dianhydride-based polyimide (PPI) composite (PANI-PPI-9). Benefiting from the core-shell structure, the PPI presents an improved electrochemical performance, especially the remarkable cycling life (503 mAh g−1 at 1.5 A g−1 after 2400 cycles). Ex-situ characterizations and kinetics analyses also verify that the PANI shell serves as the electronic transport highway without obstructing the Li storage of PPI. This work highlights the potential application of the multifarious polymer-based composite electrodes for the lithium ion batteries. • The structure construct strategy to design and prepare the PANI-coated PPI micron flowers. • Aromatic rings in the polyimide provide a large number of lithium storage sites. • The PANI-PPI-9 exhibits improved long-cycling and rate performance. [ABSTRACT FROM AUTHOR]

Abstract: A facile and green method is developed to fabricate Fe3O4–Fe nanowires with a large amount of nanoholes directly grown on highly conductive nanofiber arrays. By electrodeposition of Fe clusters on C/TiC nanofiber array, followed by in-situ chemical conversion of Fe to FeC2O4–Fe nanowires and the thermal decomposition of FeC2O4–Fe to Fe3O4–Fe, a Fe3O4–Fe nanocomposite electrode with unique architecture is successfully prepared. The electrode is characterized by means of X-ray diffractometer, scanning electron microscope and transmission electron microscope. Electrochemical properties of the nanowire arrays electrode as the anode of lithium-ion batteries are examined by cyclic voltammetry and galvanostatic charge/discharge test. The electrode displayed remarkably high capacity, excellent high rate performance and superior cycling stability. The reversible capacity of the electrode reached 1012 mAh g−1 at 1C and retained to be 500 and 255 mAh g−1 at 10 and 20C, respectively. It can still deliver a specific capacity of 100 mAh g−1 even at 50C (72 s charge–discharge). The electrode also has a satisfactory cycling performance with capacity retention of 93.9% after 100 cycles at 1C. The magnificent performance can be attributed to the distinct configuration resulting from the novel fabrication process. [Copyright &y& Elsevier]

Highlights: [•] MgFe2O4 nanoparticles are prepared by a sol–gel method. [•] The initial discharge specific capacity under the current density of 180mAg−1 reaches 1404mAhg−1. [•] The high specific capacities and good stability were due to its small particle size and the good electrochemical activity. [ABSTRACT FROM AUTHOR]

[Display omitted] • Carbon coated MoS 2 hierarchical microspheres are synthesized with PVP assistance. • MoS 2 @C display the capacity of 124 mAh/g over 700 cycles at 1000 mA g−1 for K ion batteries. • The capacitive contribution promises the rate ability and cycling performance of MoS 2 @C. • The K ions storage mechanism in MoS 2 @C is investigated via ex-situ XRD and TEM. Potassium ion batteries (PIBs) is becoming a capable battery technology that can be used for coming generation low-cost energy storage. Although conversion-type transition metal dichalcogenides have shown major application prospects as high-capacity anode in PIBs, the dramatic structural degradation of materials during the potassium ions (de)intercalation process leads to unsatisfied cycling performance and poor rate ability. Herein, we carry out an interfacial engineering strategy to design and synthesize carbon-coated MoS 2 hierarchical microspheres (MoS 2 @C) for PIBs. The uniform carbon coating layer maintains the structural integrity and the heterointerfaces in MoS 2 @C provide an electron transport highway. As a consequence, at 100 mA g-1, for the MoS 2 @C hierarchical microspheres, a remarkable capacity of 332 mAh g-1 can be obtained, with a remarkable cycling ability. Moreover, at 1000 mA g-1, MoS 2 @C can still provide the capacity of 124 mAh g-1 over 700 cycles. The kinetics analysis and ex-situ characterization demonstrated the fast and reversible K ions storage behavior of MoS 2 @C. This work is helpful to design other conversion-type electrode materials for metal ion storage systems. [ABSTRACT FROM AUTHOR]

• Sulfur-doped hemp-derived carbon is used in PIBs high-performance anodes. • It exhibits a higher capacity and better rate capability at 60 °C than at 25 °C. • Bonded sulfur is awakened at high temperature to enhance the adsorption of K +. • High temp promotes the decomposition of electrolyte is the main cause of danger. • The full cell composed of PTCDA exhibits excellent capacity at 60 °C. Potassium-ion batteries (PIBs) have huge advantages in terms of price and resource abundance, and are ideal substitutes for lithium-ion batteries (LIBs), but there is currently little research on their high-temperature fields. In this work, the sulfur-doped biomass carbon (CHP/S) is synthesized from biomass hemp stalks as the carbon source and sulfur powder as the sulfur source, with a high sulfur content of 18.6%. Sulfur mainly exist in the form of bonded sulfur (S-C, S-O) and have quite favorable stability. As a PIBs anode, it exhibits a specific capacity of 589 mAh g−1 (30 mA g−1) at 60 °C, which is 1.5 times the capacity at 25 °C. Electrochemical analysis and kinetic analysis indicate that the increased capacity mainly comes from the "arousal effect" of sulfur under high temperature conditions, and an increased temperature has a positive effect on the absorption and desorption performance of the material. In addition, the full cell assembled with Perylene-3, 4, 9, 10-tetracarboxylic dianhydride (PTCDA) cathode shows greater capacity (~80 mAh g−1) at 60 °C than at 25 °C. Unfortunately, the electrolyte decomposition problem caused by high temperature is easily dangerous. The result is of great significance to the research of high-temperature PIBs. Image, graphical abstract [ABSTRACT FROM AUTHOR]

High-quality F-doped graphene as rate capability anode for Li-ion battery is prepared by a one-step arc-discharge method. The in-situ formation of LiF nano-particles in the first lithium insertion process enhance the interlayer spacing of graphene, thus provid enough void for rapid ion diffusion, which is capable to deliver much high reversible capacity, outstanding rate performance, and excellent cycling stability. • A high-quality F-modified graphene as rate capability anode for Li-ion battery is reported. • The structural evolution of F-modified graphene electrode during the Li+ insertion/extraction is investigated. • The F-modified graphene delivers a high reversible capacity, outstanding rate performance, and excellent cycling stability. The application of lithium ion battery (LIB) in portable electronics and electric vehicle has received tremendous attention, however, challenges remain in seeking suitable high-capacity anode materials with excellent rate performance and thus potentially to boost the energy/power density. Here we report an arc-discharge production of high-quality F-modified graphene as anode for LIB with high-rate capability. As a result of F-modified, the acquired graphene exhibits high atomic ratio of C/O, excellent electric conductivity and more crumpled and wrinkled surface. Interestingly, the in-situ formation of LiF nanoparticles during the first Li+ insertion process not only act as barriers to effectively prevent the agglomeration and re-stacking of graphene sheets but also enhance the interlayer spacing, thus providing enough void for rapid Li+ ion insertion/extraction. These optimized features enable the resultant F-modified graphene delivers a high reversible capacity (783.2 mAh g−1 at 100 mA g−1), outstanding rate performance (298.5 mAh g−1 at 10 A g−1), and excellent cycling stability (>91% capacity retention after 1000 cycles), providing great application prospect in high-enegy-power LIB. [ABSTRACT FROM AUTHOR]