Recent Progress in Silicon-Based Materials for Performance-Enhanced Lithium-Ion Batteries.

Silicon (Si) has been considered to be one of the most promising anode materials for high energy density lithium-ion batteries (LIBs) due to its high theoretical capacity, low discharge platform, abundant raw materials and environmental friendliness. However, the large volume changes, unstable solid electrolyte interphase (SEI) formation during cycling and intrinsic low conductivity of Si hinder its practical applications. Various modification strategies have been widely developed to enhance the lithium storage properties of Si-based anodes, including cycling stability and rate capabilities. In this review, recent modification methods to suppress structural collapse and electric conductivity are summarized in terms of structural design, oxide complexing and Si alloys, etc. Moreover, other performance enhancement factors, such as pre-lithiation, surface engineering and binders are briefly discussed. The mechanisms behind the performance enhancement of various Si-based composites characterized by in/ex situ techniques are also reviewed. Finally, we briefly highlight the existing challenges and future development prospects of Si-based anode materials.

Innovative Materials for Energy Storage and Conversion.

The metal chalcogenides (MCs) for sodium-ion batteries (SIBs) have gained increasing attention owing to their low cost and high theoretical capacity. However, the poor electrochemical stability and slow kinetic behaviors hinder its practical application as anodes for SIBs. Hence, various strategies have been used to solve the above problems, such as dimensions reduction, composition formation, doping functionalization, morphology control, coating encapsulation, electrolyte modification, etc. In this work, the recent progress of MCs as electrodes for SIBs has been comprehensively reviewed. Moreover, the summarization of metal chalcogenides contains the synthesis methods, modification strategies and corresponding basic reaction mechanisms of MCs with layered and non-layered structures. Finally, the challenges, potential solutions and future prospects of metal chalcogenides as SIBs anode materials are also proposed.

A frogspawn inspired twin Mo2C/Ni composite with a conductive fibrous network as a robust bifunctional catalyst for advanced anion exchange membrane electrolyzers.

Anion exchange membrane water electrolysis (AEMWE) is considered one of the most cost-effective methods for producing green hydrogen. However, the performance of AEMWE is still restrained by the slow reaction kinetics and poor ion/electron transport of catalysts. Herein, inspired by frogspawn, Mo2C nanoparticles coupled with Ni were in situ embedded into a N-doped porous carbon nanofiber network (Mo2C/NCNTs@Ni) by chemical crosslinking electrospinning combined with carbonization. The unique bionic structure can guarantee favorable overall structural flexibility and fast ion/electron transport kinetics. As a result of the robust hydrogen binding energy of Mo2C, as well as the synergistic impact between Ni and Mo2C nanoparticles and the conductive network resembling frogspawn, the catalyst developed demonstrates excellent performance in both the HER and OER. When employed as a bifunctional catalyst in water electrolysis, Mo2C/NCNTs@Ni delivers overpotentials of 155 mV and 320 mV at 10 mA cm-2 for the HER and OER, respectively. In addition, the Mo2C/NCNTs@Ni also displays excellent long-term durability during a continuous operation test under different currents for 50 h. The assembled AEMWE electrolyzers with Mo2C/NCNTs@Ni as both the anode and cathode can achieve a current density of 82.5 mA cm-2 at 1.99 V, indicating great potential for industrial water splitting. These results give an insight for the development of advanced bifunctional electrocatalysts for the next generation of green and efficient H2 production by water electrolysis.

Necklace-like Si@C nanofibers as robust anode materials for high performance lithium ion batteries.

Silicon is believed to be a promising anode material for lithium ion batteries because of its highest theoretical capacity and low discharge potential. However, severe pulverization and capacity fading caused by huge volume change during cycling limits its practical application. In this work, necklace-like N-doped carbon wrapped mesoporous Si nanofibers (NL-Si@C) network has been synthesized via electrospinning method followed by magnesiothermic reduction reaction process to suppress these issues. The mesoporous Si nanospheres are wrapped with N-doped carbon shells network to form yolk-shell structure. Interestingly, the distance of adjacent Si@C nanospheres can be controllably adjusted by different addition amounts of SiO2 nanospheres. When used as an anode material for lithium ion batteries, the NL-Si@C-0.5 exhibits best cycling stability and rate capability. The excellent electrochemical performances can be ascribed to the necklace-like network structure and N-doped carbon layers, which can ensure fast ions and electrons transportation, facilitate the electrolyte penetration and provide finite voids to allow large volume expansion of inner Si nanoparticles. Moreover, the protective carbon layers are also beneficial to the formation of stable solid electrolyte interface film.

Cross-section measurement for the reactions producing short-lived nuclei induced by neutrons around 14 MeV.

The cross-sections of 180W(n,2n)179mW, 186W(n,2n)185mW, 165Ho(n,2n)164mHo, 64Ni(n,alpha)61Fe, 165Ho(n,alpha)162Tb and 51V(n,p)51Ti reactions induced by neutrons around 14 MeV were measured using activation technique and calculated by a previously developed formula in this work. The neutron flux was determined using the monitor reactions 93Nb(n,2n)92mNb and 27Al(n,alpha)24Na, the neutron energies were measured with the method of cross-section ratios for 90Zr(n,2n)89Zr to 93Nb(n,2n)92mNb reactions. The results of this work are compared with data published previously.

Cross sections for (n, 2n), (n, p) and (n, ) reactions on osmium isotopes in the neutron energy range of 13.5-14.8 MeV.

Cross sections for (n, 2n), (n, p) and (n, alpha) reactions on the osmium isotopes were measured in the neutron energies 13.5-14.8 MeV by the activation technique with the monitor reaction (93)Nb(n, 2n)(92 m)Nb. Our measurements were carried out by gamma-detection using a coaxial high-purity germanium (HPGe) detector. Natural high-purity osmium powder (99.9%) was fabricated as the samples. The neutron energies were determined by the cross-section ratios for (93)Nb(n, 2n)(92 m)Nb and (90)Zr(n, 2n)(89 m+g)Zr reactions. The fast neutrons were produced by the T(d, n)(4)He reaction. The results obtained were compared with previous data.

Uniform MnCo2O4 Porous Dumbbells for Lithium-Ion Batteries and Oxygen Evolution Reactions.

Three-dimensional (3D) binary oxides with hierarchical porous nanostructures are attracting increasing attentions as electrode materials in energy storage and conversion systems because of their structural superiority which not only create desired electronic and ion transport channels but also possess better structural mechanical stability. Herein, unusual 3D hierarchical MnCo2O4 porous dumbbells have been synthesized by a facile solvothermal method combined with a following heat treatment in air. The as-obtained MnCo2O4 dumbbells are composed of tightly stacked nanorods and show a large specific surface area of 41.30 m2 g-1 with a pore size distribution of 2-10 nm. As an anode material for lithium-ion batteries (LIBs), the MnCo2O4 dumbbell electrode exhibits high reversible capacity and good rate capability, where a stable reversible capacity of 955 mA h g-1 can be maintained after 180 cycles at 200 mA g-1. Even at a high current density of 2000 mA g-1, the electrode can still deliver a specific capacity of 423.3 mA h g-1, demonstrating superior electrochemical properties for LIBs. In addition, the obtained 3D hierarchical MnCo2O4 porous dumbbells also display good oxygen evolution reaction activity with an overpotential of 426 mV at a current density of 10 mA cm-2 and a Tafel slope of 93 mV dec-1.

Three-Dimensional Carbon-Coated Treelike Ni3S2 Superstructures on a Nickel Foam as Binder-Free Bifunctional Electrodes.

Three-dimensional (3D) nanostructures are commonly endowed with numerous active sites, large specific surface area, and good mechanical strength, which make them as an efficient candidate for energy storage and conversion. Herein, by considering the advantages of 3D nanostructures, we successfully fabricated carbon-coated nickel sulfide on a nickel foam (C@NS@NF) with a unique 3D treelike superstructure via a two-step hydrothermal process. By virtue of its hierarchical superstructures, 3D treelike architecture, and carbon shell encapsulation, the as-fabricated carbon-coated Ni3S2 can be directly served as binder-free bifunctional electrodes for supercapacitor and hydrogen evolution reaction, where high specific areal capacitance (6.086 F cm-2 at 10 mA cm-2) for supercapacitors and low overpotential (92 mV at 10 mA cm-2) for the electrocatalyst have been demonstrated. These inspiring results of this material make it as a potential candidate for energy storage and conversion.

Half-life of 176Lu.

The half-life of 176Lu, measured using gamma-ray spectrometry, has been found to be (3.56+/-0.07)x10(10)yr. Comparison has been made between present results and literature data.

Cross-section measurements for the reactions of 14 MeV neutrons on indium isotopes.

The cross sections for the reactions (115)In(n, p)(115g)Cd, (115)In(n, alpha)(112)Ag, (115)In(n, 2n)(114m)In, (113)In(n, 2n)(112m)In, (115)In(n, n')(115m)In, and (113)In(n, n')(113m)In induced by 14 MeV neutrons have been measured by activation relative to the (27)Al(n, alpha)(24)Na. Measurements were carried out by gamma-detection using a coaxial HPGe detector. As samples, natural indium has been used. The fast neutrons were produced by the T(d, n)(4)He reaction. The results obtained are compared with existing data.

Cross-section measurements for the 128Te(n,2n) 127mTe reaction induced by neutrons around 14 MeV.

The cross sections of 128Te(n,2n) 127mTe reaction induced by neutrons around 14 MeV were measured using activation technique and calculated by a previously developed formula. 737+/-69 and 853+/-82 mb at the neutron energies of 14.1+/-0.2 and 14.6+/-0.3 MeV, respectively; these are in good agreement with those published by other workers.

Cross-section measurements for (n, 2n), (n, p) and (n, n'alpha) reactions on gallium isotopes in the neutron energy range of 13.5-14.6 MeV.

Cross-sections for (n, 2n), (n, p) and (n, n'alpha) reactions have been measured on gallium isotopes at the neutron energies of 13.5-14.6MeV using the activation technique. Data are reported for the following reactions: 69Ga(n, 2n) 68Ga, 69Ga(n, p) 69mZn, 71Ga(n, p) (71m)Zn, and 71Ga(n, n'alpha) 67Cu. The neutron fluences were determined using the monitor reaction 93Nb(n, 2n) 92mNb.

Cross section measurements for (n, 3n) reactions induced by 14.8 MeV neutrons.

The cross sections for 209Bi(n, 3n)207Bi, 191Ir(n, 3n)189Ir, 151Eu(n, 3n)149Eu and 185Re(n, 3n)183Re reactions were measured by the activation method. The experimental results were 12.1+/-1.1, 64.6+/-6.5, 2.7+/-0.4 and 66.0+/-5.6 mb at the neutron energy of 14.8+/-0.2 MeV, respectively. The neutron flux was determined by the cross section of the 27Al(n, alpha)24Na reaction. The neutron energy in these measurements was determined by the method of cross section ratios for 90Zr(n, 2n)(89m + g)Zr and 93Nb(n, 2n)92mNb reactions.

Measurement of fission cross section for 232Th(n,x)89Rb reaction induced by neutrons around 14 MeV.

In order to investigate the fission process in more detail, and to compare with the measurement of cumulative fission yields, the fission cross section of the (232)Th(n,x)(89)Rb reaction induced by 14 MeV neutron was measured using the activation technique. In our measurement the neutron flux was determined using the monitor (27)Al(n,α)(24)Na reaction, and the neutron energies were measured by the method of cross-section ratios of (90)Zr(n,2n)(89)Zr to (93)Nb(n,2n)(92m)Nb reactions. The cross sections were deduced as 14.0±0.9 mb at E(n)=14.7±0.3 MeV and 13.2±1.0 mb at E(n)=14.1±0.3 MeV.

Activation cross-sections for (158)Dy(n,p)(158)Tb, (156)Dy(n,alpha)(153)Gd and (160)Dy(n,p)(160)Tb reactions induced by neutrons at 14.7MeV.

The cross-sections for the (158)Dy(n,p)(158)Tb, (156)Dy(n,alpha)(153)Gd and (160)Dy(n,p)(160)Tb reactions induced by 14.7MeV neutrons were measured in this work and calculated by a previously developed formula. Measurements were corrected for gamma-ray attenuations, random coincidence (pile-up), dead time and fluctuation of neutron flux. Nuclear model calculations using the code HFTT, which employs the Hauser-Feshbach (statistical model) and exciton model (precompound effects) formalisms, were undertaken to describe the formation of the products.

Measurements of activation cross-sections for the 96Ru(n,d*)95gTc reaction for neutrons with energies between 13.3 and 15.0MeV.

In this study, activation cross-sections were measured for the (9)(6)Ru(n,d*)(95g)Tc reaction at three different neutron energies from 13.5 to 14.8MeV. The fast neutrons were produced via the (3)H(d,n)(4)He reaction on a K-400 neutron generator. Induced gamma activities were measured by a high-resolution gamma-ray spectrometer with a high-purity germanium (HPGe) detector. Measurements were corrected for gamma-ray attenuations, random coincidence (pile-up), dead time and fluctuation of neutron flux. The data for (9)(6)Ru(n,d*)(95g)Tc reaction cross-sections are reported to be 196+/-18, 253+/-22 and 298+/-22mb at 13.5+/-0.2, 14.1+/-0.1 and 14.8+/-0.2MeV incident neutron energies, respectively. Results were compared with the previous works.

Cross-section measurements for (n, 2n) and (n, alpha) reactions on yttrium at neutron energies from 13.5 to 14.6 MeV.

The cross sections for the reactions (89)Y(n, 2n) (88m+g)Y and (89)Y(n, alpha) (86m+g)RB induced by 14MeV neutrons have been measured using the activation technique and a coaxial HPGe gamma-ray detector. Spectroscopically pure Y(2)O(3) powder was used. Fast neutrons were produced by the T(d, n) (4)He reaction. The neutron fluencies were determined using the monitor reaction (93)Nb(n, 2n) (92m)Nb.