Ultra-high Energy Research Articles

Modified Characteristics of Hadronic Interactions in Ultra-High-Energy Cosmic-Ray Showers

Data from multiple experiments suggest that the current interaction models used in Monte Carlo simulations do not correctly reproduce the hadronic interactions in air showers produced by ultra-high-energy cosmic rays (UHECR), in particular – but not limited to – the production of muons during the showers. We have created a large library of UHECR simulations where the interactions at the highest energies are slightly modified in various ways – but always within the constraints of the accelerator data, without any abrupt changes with energy and without assuming any specific mechanism or dramatically new physics at the ultra-high energies. We will find that even when very different properties – cross section, elasticity, and multiplicity – of the interactions are modified, the resulting changes in some air-shower observables are still mutually correlated. Thus, not all possible combinations of changes of observables are easily reproduced by some combination of the modifications. Most prominently, the recent results of the Pierre Auger Observatory, which call for a change in the prediction of both the muon content at ground and the depth of the maximum of longitudinal development of the showers, are rather difficult to reproduce with such modifications, in particular when accounting for other cosmic-ray data. While some of these results are related to the assumptions we place on the modifications, the overall lessons are general and provide valuable insight into how the UHECR data can be interpreted from the point of view of hadronic physics.

The Spin‐Selective Channels in Fully‐Exposed PtFe Clusters Enable Fast Cathodic Kinetics of Li‐O2 Batter y

In Li‐O2 batteries (LOBs), the electron transfer between triplet O2 and singlet Li2O2 possesses a spin‐dependent character but is still neglected, while the spin‐conserved electron transfer without losing phase information should guarantee fast kinetics and reduced energy barriers. Here, we provide a paradigm of spin‐selective catalysis for LOB that the ferromagnetic quantum spin exchange interactions between Pt and Fe atoms in fully‐exposed PtFe clusters filter directional e‐spins for spin‐conserved electron transfer at Fe‐Fe sites. The kinetics of O2/Li2O2 redox reaction is markedly accelerated as predicted by theoretical calculations, showing dramatically decreased relaxation time of the rate determining step for more than one order of magnitude, compared with the Fe clusters without spin‐selective behavior. In consequence, the assembled LOB provides ultrahigh energy conversion efficiency of 89.6% at 100 mA g‐1 under a discharge‐charge overpotential of only 0.32 V. This work provides new insights into the spin‐dependent mechanisms of O2/Li2O2 redox reaction, and the strategy of constructing spin catalysts at atomic level.

The Spin-Selective Channels in Fully-Exposed PtFe Clusters Enable Fast Cathodic Kinetics of Li-O2 Batter y.

In Li-O2 batteries (LOBs), the electron transfer between triplet O2 and singlet Li2O2 possesses a spin-dependent character but is still neglected, while the spin-conserved electron transfer without losing phase information should guarantee fast kinetics and reduced energy barriers. Here, we provide a paradigm of spin-selective catalysis for LOB that the ferromagnetic quantum spin exchange interactions between Pt and Fe atoms in fully-exposed PtFe clusters filter directional e-spins for spin-conserved electron transfer at Fe-Fe sites. The kinetics of O2/Li2O2 redox reaction is markedly accelerated as predicted by theoretical calculations, showing dramatically decreased relaxation time of the rate determining step for more than one order of magnitude, compared with the Fe clusters without spin-selective behavior. In consequence, the assembled LOB provides ultrahigh energy conversion efficiency of 89.6% at 100 mA g-1 under a discharge-charge overpotential of only 0.32 V. This work provides new insights into the spin-dependent mechanisms of O2/Li2O2 redox reaction, and the strategy of constructing spin catalysts at atomic level.

Dense integration of chlorocatechols crosslinked polyphenylene sulfide solid-state separator for Li Metal-Free Batteries

Dry electrode film fabrication technology, known for its environmental friendliness and low energy consumption, is recognized as an effective industrial approach for producing highly dense solid-state electrolytes and pore-free separators. It holds promise for applying thin lithium metal and Li metal-free anodes in ultra-high energy density Li-ions batteries. However, the films produced by this method suffer from issues such as poor toughness, low strength, uneven thickness, and difficulties in rewinding, which limit its widespread adoption in the large-scale manufacturing of lithium batteries. In this study, we propose a hydrothermal process to introduce a chlorocatechol-based cross-linker onto the surface of highly crystalline polyphenylene sulfide (PPS) powder. By employing the dry electrode process, a PPS-based solid-state separator (PPS-SSS) is fabricated, featuring a thin profile (18±2 μm), a smoother surface, and a denser structure, significantly enhancing its mechanical properties. Moreover, the dense integration structure and chlorocatechol groups contribute to a higher Li+ transference number and more effectively inhibit the growth of Li dendrites. Li metal-free batteries, constructed with this separator, a Sn-plated Cu 10 μm foil anode, and a thick high-nickel cathode dry electrode, exhibit high discharge areal and specific capacities (5 mAh cm−2 and 200 mAh g−1, respectively) and pouch battery device energy density exceeding 440 Wh kg−1. Impressively, even in the presence of Cu or Fe powder contamination on the CuSn foil anode or cathode, this separator can still achieve uniform electric field distribution and lithium deposition, demonstrating good cycle stability.

Ultrahigh Energy and Power Density in Ni–Zn Aqueous Battery via Superoxide-Activated Three-Electron Transfer

HighlightsEfficient activation of Ni electrode employs chronopotentiostatic superoxidation.Novel superoxide activation mechanism realizes the redox reaction with three-electron transfer (Ni ↔ Ni3+).As-prepared CPS-Ni||Zn batteries exhibit simultaneously ultrahigh energy and power densities.

Constructing local structure heterogeneity in AgNbO3-based antiferroelectrics: Achieving excellent anti-fatigue and energy storage properties

AgNbO3 ceramics are important candidates for developing high-property dielectric capacitors because of their unique field-induced antiferroelectric (AFE)-ferroelectric (FE) phase transformation behavior and good environmental friendliness. However, until now, they have not yet exhibited simultaneously ultrahigh recoverable energy density (Wrec) and efficiency (η), and superior electrical fatigue resistance. Herein, we design a heterovalence-doping-enabled local structure heterogeneity strategy to achieve AgNbO3-based ceramics with excellent anti-fatigue and capacitive characteristics. The replacement of A-site Ag+ with higher valence Sm3+, and the substitution of lower electronegativity Ta5+ for B-site Nb5+ decrease the [Nb/TaO6] octahedral tilting, destroy the long-range ordering of AFE domains and produce low-atom-displacement regions, as confirmed by the atomic-scale electron microscopy. These are in favor of improving AFE features, refining P-E curves, and decreasing electric field-induced strain. Consequently, an ultrahigh Wrec of 8.03 J/cm3, and a large η of 74.77 % are obtained in the (Ag0.94Sm0.02)(Nb0.75Ta0.25)O3 ceramic. More interestingly, the Wrec and η both show excellent anti-fatigue characteristics with less than 2.6 % degradation even after 106 cycles, far superior to those obtained in other AgNbO3 systems with only 104 cycle stability.

Lμ−Lτ solution to the IceCube ultrahigh-energy neutrino deficit in light of NA64

In this work we analyze the scenario where a MeV scale Lμ−Lτ gauge boson can explain the deficit in the diffuse ultrahigh-energy (UHE) astrophysical neutrino spectrum observed in IceCube, as well as the discrepancy between experimental and e+e− scattering data-driven Standard Model calculations of the muon anomalous magnetic moment. We map the parameter space of the model where the elastic resonant s-channel scattering of UHE neutrinos with the cosmic neutrino background, mediated by the new Z′, can improve the description of the observed cascade and track spectra over the no-scattering hypothesis. Comparing to recent NA64-μ results, we find that some part of the parameter space remains unexplored, but at a data volume of 1011 muons on target NA64-μ will completely probe this region. Published by the American Physical Society 2024

Cosmic rays from annihilation of heavy dark matter particles

The origin of the ultra high energy cosmic rays via annihilation of heavy stable, fermions “f”, of the cosmological dark matter (DM) is studied. The particles in question are supposed to be created by the scalaron decays in R2 modified gravity. The novel part of our approach is the assumption that the mass of these carriers of DM is slightly below than a half of the scalaron mass. In such a case the phase space volume becomes tiny. It leads to sufficiently low probability of “f” production, so their average cosmological energy density could be equal to the observed energy density of dark matter. Several regions of the universe, where the annihilation could take place, are studied. They include the whole universe under the assumption of homogeneous energy density, the high density DM clump in the galactic center, the cloud of DM in the Galaxy with realistic density distribution, and high density clumps of DM in the Galaxy. Possible resonance annihilation of ff¯ into energetic light particles is considered. We have shown that the proposed scenario can successfully explain the origin of the ultrahigh energy flux of cosmic rays where canonical astrophysical mechanisms are not operative.

Study on structure and electrical properties of BNBT-La2/3ZrO3 ceramic

BNT-based energy storage dielectric material is a new type of multifunctional material with environmental friendliness, high energy storage density, and excellent temperature stability. It is a research hotspot where different components are introduced into BNT-based ceramics to obtain ceramic materials with high energy storage density. In this study, 0.94Bi0.5Na0.5TiO3-0.06BaTiO3 (BNBT) was selected as the substrate and doped with La2/3ZrO3 (LZ). Through the modification of La3+/Zr4+ at A/B sites, wider optical bandgap and finer grains with exceptionally large electrical breakdown strength and relatively strong relaxation behaviors in the appropriate range were obtained. Ultimately, an ultra-high energy storage density of 6.48 J/cm3 was attained at 480 kV/cm with a La2/3ZrO3 concentration of 0.07 mol%. In addition, the BNBT-LZ ceramics exhibited a good frequency-stabilized dynamic range (Wrec = 3.29 ± 6.7 % J/cm³, 10–200 Hz) and temperature stability (Wrec = 3.63 ± 9.9 % J/cm³, 20–160 °C), together with excellent charge-discharge performance(t0.9 = 3.36 μs). All these characteristics demonstrate that the modification of BNT-based ceramics by La3+/Zr4+ has a significant effect on the energy storage density. The results show that the BNBT-LZ system can be used as a promising dielectric material for high energy storage density capacitors.

Aperture correction for beamforming in the radiometric detection of ultrahigh energy cosmic rays

Aperture correction for beamforming in the radiometric detection of ultrahigh energy cosmic rays

Decoupling enhancements of breakdown strength and dielectric constant in PMIA-based composite films for high-temperature capacitive energy storage

Polymer-based dielectric films are increasingly demanded for capacitive energy storage. However, the negative coupling between dielectric constant (ɛr) and breakdown strength (Eb) presents a significant challenge to further enhancements, especially at high temperatures. Here, we propose dielectric composite films employing poly(m-phenylene isophthalamide) (PMIA) as the matrix, with nanodiamond (ND) particles modified by polydopamine (PDA) serving as reinforcing fillers. At 150 °C, the 1.0 wt% film demonstrates an ultrahigh discharge energy density (Ue) of 5.15 J/cm3 at a charge-discharge efficiency (η) exceeding 90 %. Even the temperature increases to 200 °C, the film maintains a desirable Ue of 2.36 J/cm3 with η > 90 %, achieving a record energy storage performance that outperforms numerous previous works. In addition to the inherent hydrogen bonds among PMIA molecular chains, ND@PDA fillers, enriched with hydroxyl groups, facilitate the formation of additional hydrogen bonds with PMIA, generating a hydrogen bonding network. This network provides additional dipoles for overall polarization, enhances Young's modulus for electromechanical resistance, and suppresses dielectric loss upon temperature increase, thereby reducing conduction loss. Both experimental and simulation results indicate that this hydrogen bonding network is extremely stable at high temperatures, effectively promoting the decoupling enhancements of ɛr and Eb for high-temperature energy storage applications.

Hansen Solubility Parameter-Guided Solvent Selection for Solution-Phase Discharge in Li-CO2 Batteries.

Surface discharge mechanism-induced cathode passivation is a critical challenge that blocks the full liberation of the ultrahigh theoretical energy density of Li-CO2 batteries. Herein, we propose a novel concept based on Hansen solubility parameters (HSPs) to guide the selection of solvents for inducing the dissolution of discharge products, facilitating the detachment of in situ-formed metastable Li2C2O4 from the electrode surface and enabling a continuous Li2C2O4-dominated discharge process. Combining theoretical calculations with HSP predictions, we identified Pd-OCNTs as an ideal catalyst, with tetraethylene glycol dimethyl ether as the optimal solvent for Li2C2O4 production and stabilization. This combination facilitates the rapid diffusion of Li2C2O4 generated in situ near the catalyst surface out of the inner Helmholtz layer. Consequently, the system exhibits high energy efficiency of 96.7% and remarkable stability over 3200 h. This work provides critical insights into the solution-mediated dissolution process of Li2C2O4, informing strategies for multiphase interfacial reactions in Li-CO2 batteries.

Thienothiophene-Benzopyran Derivative and AQ4N-Assembled Liposomes for Near-Infrared II Fluorescence Imaging-Guided Phototherapy, Chemotherapy, and Immune Activation.

Phototherapy, including photodynamic therapy (PDT) and photothermal therapy (PTT), has attracted wide attention in tumor treatment. However, the hypoxic tumor microenvironment and the heat shock proteins produced by tumor cells significantly reduce their efficacy. Developing effective phototherapy agents that have high reactive oxygen species generation efficiency and photothermal conversion efficiency (PCE) while simultaneously utilizing the hypoxic tumor microenvironment is of great importance. Here, a thienothiophene-benzopyran derivative, BTPIC4F-C10 is designed and synthesized, with near-infrared (NIR) absorption and fluorescence. Then the lipid nanoparticles (LipBFCA NPs) which encapsulated BTPIC4F-C10 in a phospholipid bilayer together with hypoxia-activated prodrug banoxanthrone (AQ4N) are constructed for NIR-II fluorescence imaging-guided synergistic PDT/PTT/chemotherapy and immune activation. Under 808nm laser irradiation, LipBFCA NPs is a high singlet oxygen quantum yield of 20.2% and PCE of 78.8%. With ultra-high photon energy utilization efficiency of 99%, LipBFCA NPs is an excellent phototherapy effect. The hypoxic environment caused by phototherapy can further activate AQ4N to transform into chemically toxic AQ4 radicals to kill tumor cells. Moreover, phototherapy can induce immunogenic cell death, release tumor-associated antigens, and activate immune responses. This work provides a new way for the clinical application of fluorescence imaging in guiding tumor diagnosis and treatment.

Establishing Non-Stoichiometric Ti4O7 Assisted Asymmetrical C-C Coupling for Highly Energy-Efficient Electroreduction of Carbon Monoxide.

Exploring an appropriate support material for Cu-based electrocatalyst is conducive for stably producing multi-carbon chemicals from electroreduction of carbon monoxide. However, the insufficient metal-support adaptability and low conductivity of the support would hinder the C-C coupling capacity and energy efficiency. Herein, non-stoichiometric Ti4O7 was incorporated into Cu electrocatalysts (Cu-Ti4O7), and served as a highly conductive and stable support for highly energy-efficient electrochemical conversion of CO. The abundant oxygen vacancies originated from ordered lattice defects in Ti4O7 facilitate the water dissociation and the CO adsorption to accelerate the hydrogenation to *COH. The highly adaptable metal-support interface of Cu-Ti4O7 enables a direct asymmetrical C-C coupling between *CO on Cu and *COH on Ti4O7, which significantly lowers the reaction energy barrier for C2+ products formation. Additionally, the excellent electroconductivity of Ti4O7 benefits the reaction charge transfer through robust Cu/Ti4O7 interface for minimizing the energy loss. Thus, the optimized 20Cu-Ti4O7 catalyst exhibits an impressive selectivity of 96.4 % and ultrahigh energy efficiency of 45.1 % for multi-carbon products, along with a remarkable partial current density of 432.6 mA cm-2. Our study underscores a novel C-C coupling strategy between Cu and the support material, advancing the development of Cu-supported catalysts for highly efficient electroreduction of carbon monoxide.

Establishing Non‐Stoichiometric Ti4O7 Assisted Asymmetrical C−C Coupling for Highly Energy‐Efficient Electroreduction of Carbon Monoxide

AbstractExploring an appropriate support material for Cu‐based electrocatalyst is conducive for stably producing multi‐carbon chemicals from electroreduction of carbon monoxide. However, the insufficient metal‐support adaptability and low conductivity of the support would hinder the C−C coupling capacity and energy efficiency. Herein, non‐stoichiometric Ti4O7 was incorporated into Cu electrocatalysts (Cu−Ti4O7), and served as a highly conductive and stable support for highly energy‐efficient electrochemical conversion of CO. The abundant oxygen vacancies originated from ordered lattice defects in Ti4O7 facilitate the water dissociation and the CO adsorption to accelerate the hydrogenation to *COH. The highly adaptable metal‐support interface of Cu−Ti4O7 enables a direct asymmetrical C−C coupling between *CO on Cu and *COH on Ti4O7, which significantly lowers the reaction energy barrier for C2+ products formation. Additionally, the excellent electroconductivity of Ti4O7 benefits the reaction charge transfer through robust Cu/Ti4O7 interface for minimizing the energy loss. Thus, the optimized 20Cu−Ti4O7 catalyst exhibits an impressive selectivity of 96.4 % and ultrahigh energy efficiency of 45.1 % for multi‐carbon products, along with a remarkable partial current density of 432.6 mA cm−2. Our study underscores a novel C−C coupling strategy between Cu and the support material, advancing the development of Cu‐supported catalysts for highly efficient electroreduction of carbon monoxide.

Operando Optical Imaging of Cathode Swelling Process Inside Lithium Primary Batteries: Comparative Studies between Different Structured CFx.

As a crucial cathode material with ultrahigh theoretical capacity (865 mAh/g) and energy density (>2100 Wh/kg), fluorinated carbon (CFx) is promising for lithium primary batteries. However, the operating performance of CFx cathode is hindered by nonuniform volume expansion during discharging. To investigate this, we used operando confocal microscopy to visualize the thickness evolution of two different CFx cathodes and quantified their swelling ratios as a function of the discharge depth. Our findings show that CFx synthesized from hard carbon (FHC), featuring a disordered structure and abundant pores, exhibits a swelling ratio lower than that of conventional layered fluorinated graphite (FG). This is due to different electrochemical mechanisms: lithium enters FG interlayers nonuniformly through "edge propagation" pathways while lithiation occurs homogeneously in FHC, unraveled by single-particle Raman and photoluminescence measurement. This work enhances our understanding on CFx volume expansion, offering important opportunities to address the cathode swelling issue and optimize electrochemical performance in Li/CFx batteries.

Multifunctional Ultrathin Ti3C2Tx MXene@CuCo2O4 /PE Separator for Ultra-High-Energy-Density and Large-Capacity Lithium-Sulfur Pouch Cells.

The shuttling of lithium polysulfides (LiPSs), sluggish reaction kinetics, and uncontrolled lithium deposition/stripping remain the main challenges in lithium-sulfur batteries (LSBs), which are aggravated under practical working conditions, i.e., high sulfur loading and lean electrolyte in large-capacity pouch cells. This study introduces a Ti3C2Tx MXene@CuCo2O4 (MCC) composite on a polyethylene (PE) separator to construct an ultrathin MXene@CuCo2O4/PE (MCCP) film. The MCCP functional separator can deliver superior LiPSs adsorption/catalysis capabilities via the MCC composite and regulate the Li+ deposition through a conductive Ti3C2Tx MXene framework, enhancing redox kinetics and cycling lifetime. When paired with sulfur/carbon (S/C) cathode and lithium metal anode, the resultant 10 Ah-level pouch cell with the ultrathin MCCP separator achieves an energy density of 417Wh kg-1 based on the whole cell and a stable running of 100 cycles under practical operation conditions (cathode loading = 10.0 mg cm-2, negative/positive areal capacity ratio (N/P ratio) = 2, and electrolyte/sulfur weight ratio (E/S ratio) = 2.6 µL mg-1). Furthermore, through a systematic evaluation of the as-prepared Li-S pouch cell, the study unveils the operational and failure mechanisms of LSBs under practical conditions. The achievement of ultrahigh energy density in such a large-capacity lithium-sulfur pouch cell will accelerate the commercialization of LSBs.

Ultra-high energy storage efficiency achieved through the construction of interlocking microstructure and excitation of depressor effects

Glass-ceramic capacitors struggle to balance high energy storage efficiency (η>90 %) and sufficient breakdown field strength (Eb), hindering their use in energy storage. Interface polarization, caused by the accumulation of free charge, reduces breakdown strength. We prepared glass-ceramic materials with varying contents of the glass phase using traditional melting techniques, adjusting the glass content to enhance an interlocking structure between the glass and crystal phases, reducing Interface polarization. Divalent metal oxide BaO in the glass stimulated a depressor effect, filling gaps and increasing resistivity. The optimal composition (x = 0.2) achieved a 95 % energy storage efficiency and an energy storage density of 4.4 J/cm3 at 680 kV/cm, while x = 0.25 reached an ultra-high energy storage efficiency of 99 %. Increasing glass content reduced activation energy for Interface polarization (Ei) from 1.27 eV to 1.08 eV. Samples with x = 0.2 exhibited low dielectric loss (∼0.005), high dielectric constant (∼142), ultra-high power density (∼52.8 MW/cm3), and ultra-fast discharge speed (∼26 ns), suggesting future potential for high-performance glass-ceramic materials.

Interfacial Electric Field Enhanced Free-Standing VO2/rGO Aerogel Anode with Ultra High Mass Energy Density for Aqueous Ammonium Ion Battery.

Aqueous batteries have become a promising means of energy storage due to its environmental friendliness. Nevertheless, it often exhibits limited energy density that hinder their application. Considering that ammonium ion (NH4 +) has a low mass and a small hydration radius, aqueous ammonium ion batteries (AAIBs) are expected to solve the problem of low energy density. Herein, we obtain Vanadium dioxide/reduced graphene oxide aerogel (VOGA) by in-situ growth of VO2 on the graphene surface for interfacial electric field enhanced AAIBs to achieve high mass energy density. The VOGA free-standing electrode achieves a specific capacity of up to 655 mAg-1 at a current density of 0.5 Ag-1. And the mass energy density of the VOGA.

Vapor-phase conversion of waste silicon powders to silicon nanowires for ultrahigh and ultra-stable energy storage performance

Silicon nanowires (SiNWs) have been used in a wide variety of applications over the past few decades due to their excellent material properties. The only drawback is the high production cost of SiNWs. The preparation of SiNWs from photovoltaic waste silicon (WSi) powders, which are high-volume industrial wastes, not only avoids the secondary energy consumption and environmental pollution caused by complicated recycling methods, but also realizes its high-value utilization. Herein, we present a method to rapidly convert photovoltaic WSi powders into SiNWs products. The flash heating and quenching provided by carbothermal shock induce the production of free silicon atoms from the WSi powders, which are rapidly reorganized and assembled into SiNWs during the vapor-phase process. This method allows for the one-step composite of SiNWs and carbon cloth (CC) and the formation of SiC at the interface of the silicon (Si) and carbon (C) contact to create a stable chemical connection. The obtained SiNWs-CC (SiNWs@CC) composites can be directly used as lithium anodes, exhibiting high initial coulombic efficiency (86.4%) and stable cycling specific capacity (2437.4 mA h g−1 at 0.5 A g−1 after 165 cycles). In addition, various SiNWs@C composite electrodes are easily prepared using this method.