ZnSe/SnSe Heterostructure Incorporated with Selenium/Nitrogen Co-Doped Carbon Nanofiber Skeleton for Sodium-Ion Batteries.

Effective strategies toward building exquisite nanostructures with enhanced structural integrity and improved reaction kinetics will carry forward the practical application of alloy-based materials as anodes in batteries. Herein, a free-standing 3D carbon nanofiber (CNF) skeleton incorporated with heterostructured binary metal selenides (ZnSe/SnSe) nanoboxes is developed for Na-ion storage anodes, which can facilitate Na+ ion migration, improve structure integrity, and enhance the electrochemical reaction kinetics. During the carbonization and selenization process, selenium/nitrogen (Se/N) is co-doped into the 3D CNF skeleton, which can improve the conductivity and wettability of the CNF matrices. More importantly, the ZnSe/SnSe heterostructures and the Se/N co-doping CNFs can have a synergistic interfacial coupling effect and built-in electric field in the heterogeneous interfaces of ZnSe/SnSe hetero-boundaries as well as the interfaces between the CNF matrix and the selenide heterostructures, which can enable fast ion/electron transport and accelerate surface/internal reaction kinetics for Na-ion storage. The ZnSe/SnSe@Se,N-CNFs exhibit superior Na-ion storage performance than the comparative ZnSe/SnSe, ZnSe and SnSe powders, which deliver an excellent rate performance (882.0, 773.6, 695.7, 634.2, and 559.0 mAh g-1 at current rates of 0.1, 0.2, 0.5, 1, and 2 A g-1) and long-life cycling stability of 587.5 mAh g-1 for 3500 cycles at 2 A g-1.

Tailoring NiO Nanostructured Arrays by Sulfate Anions for Sodium-Ion Batteries.

In this contribution, a novel sulfate-ion-controlled synthesis is developed to fabricate freestanding nickel hydroxide nanoarrays on Ni substrate. As an inorganic morphology-controlled agent, SO42- ions play a critical role in controlling the crystal growth and the nanoarray morphologies, by modulating the growth rate of adsorbed crystal facets or inserting into the metal hydroxide interlayers. By controlling the SO42- concentration, the nanostructured arrays are tailored from one-dimensional (1D) Ni(SO4 )0.3 (OH)1.4 nanobelt arrays to hierarchical ß-Ni(OH)2 nanosheet arrays. With further graphene oxide modification and postheat treatment, the obtained NiO/graphene hybrid nanoarrays show great potential for high-performance sodium-ion batteries, which exhibit a cyclability of 380 mAh g-1 after undergoing 100 cycles at 0.5 C and reach a rate capability of 335 mA h g-1 at 10 C.

Hydrolysis-Coupled Redox Reaction to 3D Cu/Fe3O4 Nanorod Array Electrodes for High-Performance Lithium-Ion Batteries.

A facile hydrolysis-coupled redox (HCR) reaction followed by postheating reduction has been designed to prepare unique 3D Cu/Fe3O4 core-shell nanorod array anodes. Fe2+ ions from fresh FeSO4 solution have been hydrolyzed and oxidized to form an Fe(OH)3 shell on the surface of Cu(OH)2 nanorods; meanwhile the resulting acidic environment induces the reduction of Cu(OH)2 to Cu2O, which realizes an unusual redox reaction between Fe2+ ions and Cu(OH)2. The reaction procedure and thermodynamics possibility between Fe2+ ions and Cu(OH)2 nanorod arrays are discussed from the aspect of electrode potentials. After postheating reduction in Ar/H2, the obtained 3D architecture of Cu current collector serves as a stout support for the Fe3O4 shell to form nanorod array anodes without using any binders or conducting agents. The resulting highly stable core-shell structure facilitates rapid and high-throughput transport pathways for ions/electrons and allows better accommodation of volume change during the repeated lithiation/delithiation. Its application as anodes in combination with LiNi0.5Mn1.5O4 cathodes for full cells demonstrates superior rate capability, enhanced energy density, and long cycling life.

Self-sustained cycle of hydrolysis and etching at solution/solid interfaces: a general strategy to prepare metal oxide micro-/nanostructured arrays for high-performance electrodes.

Assembling micro-/nanostructured arrays on conducting substrates allows the integration of multiple functionalities into modern electronic devices. Herein, a novel self-sustained cycle of hydrolysis and etching (SCHE) is exploited to selectively synthesize an extensive series of metal oxide micro-/nanostructured arrays on a wide range of metal substrates, establishing the generality and efficacy of the strategy. To demonstrate the potential application of this method, the as-prepared NiO porous nanobelt array was directly used as the anode for lithium-ion batteries, exhibiting excellent capacity and rate capability. Conclusively, the SCHE strategy offers a systematic approach to design metal oxide micro-/nanostructured arrays on metal substrates, which are valuable not only for lithium-ion batteries but also for other energy conversion and storage systems and electronic devices at large.

Stable electrode/electrolyte interfaces regulated by dual-salt and localized high-concentration strategies for high-voltage lithium metal batteries.

High-voltage lithium metal batteries (LMBs) have faced application obstacles derived from the unstable interfacial layers on both the cathode and anode sides. Herein, a dual-salt localized high-concentration electrolyte (LHCE) is optimized to modify the anion-derived inorganic-rich interfacial layers with conductive inorganic and robust organic components.

Cationic Defect-Modulated Li-Ion Migration in High-Voltage Li-Metal Batteries.

Li metal exhibits high potential as an anode material for next-generation high-energy density batteries. However, the nonuniform transport of Li+ ions causes Li-dendrite growth at the metal electrode, leading to severe capacity decay and a short cycling life. In this study, negatively charged lithiophilic sites (such as cationic metal vacancies) were used as hosts to regulate the atomic-scale Li+-ion deposition in Li-metal batteries (LMBs). As a proof of concept, three-dimensional (3D) carbon nanofibers (CNFs) decorated with negatively charged TiNbO4 grains (labeled CNF/nc-TNO) were confirmed to be promising Li hosts. Cationic vacancies caused by the carbothermal reduction of Nb5+ and Ti4+ ions generated a negatively charged fiber surface and strong electrostatic interactions that guided the Li+-ion flux to the shadowed areas underneath the fiber and throughout the fibrous mat. Consequently, circumferential Li-metal plating was observed in the CNF/nc-TNO host, even at a high current density of 10 mA cm-2. Moreover, CNF/nc-TNO asymmetric cells delivered a significantly more robust and stable Coulombic efficiency (CE) (99.2% over 380 cycles) than cells comprising electrically neutral CNFs without cationic defects (which exhibits rapid failure after 20 cycles) or Cu foil (which exhibits rapid CE decay, with a CE of 87.1% after 100 cycles). Additionally, CNF/nc-TNO exhibited high stability and low-voltage hysteresis during repeated Li plating/stripping (for over 4000 h at 2 mA cm-2) with an areal capacity of 2 mAh cm-2. It was further paired with high-voltage LiNi0.8Co0.1Mn0.1 (NCM811) cathodes, and the full cells showed long-term cycling (220 cycles) with a CE of 99.2% and a steady rate capability.

Defective Fe3 O4- x Few-Atom Clusters Anchored on Nitrogen-Doped Carbon as Efficient Oxygen Reduction Electrocatalysts for High-Performance Zinc-Air Batteries.

It remains a challenge to develop cost-effective, high-performance oxygen electrocatalysts for rechargeable metal-air batteries. Herein, zinc-mediated zeolitic imidazolate frameworks are exploited as the template and nitrogen and carbon sources, onto which is deposited a Fe3 O4 layer by plasma-enhanced atomic layer deposition. Controlled pyrolysis at 1000 °C leads to the formation of high density of Fe3 O4- x few-atom clusters with abundant oxygen vacancies deposited on an N-doped graphitic carbon framework. The resulting nanocomposite (Fe3 O4- x /NC-1000) exhibits a markedly enhanced electrocatalytic performance toward oxygen reduction reaction in alkaline media, with a remarkable half-wave potential of +0.930 V versus reversible hydrogen electrode, long-term stability, and strong tolerance against methanol poisoning, in comparison to samples prepared at other temperatures and even commercial Pt/C. Notably, with Fe3 O4- x /NC-1000 as the cathode catalyst, a zinc-air battery delivers a high power density of 158 mW cm-2 and excellent durability at 5 mA cm-2 with stable 2000 charge-discharge cycles over 600 h. This is ascribed to the ready accessibility of the Fe3 O4- x catalytic active sites, and enhanced electrical conductivity, oxygen adsorption, and electron-transfer kinetics by surface oxygen vacancies. Further contributions may arise from the highly conductive and stable N-doped graphitic carbon frameworks.

Double-Enhanced Core-Shell-Shell Sb2S3/Sb@TiO2@C Nanorod Composites for Lithium- and Sodium-Ion Batteries.

For most alloying- and conversion-type anode materials, a huge volume expansion and structure degradation of the electrodes always hinder their applications. In this work, a novel core-shell-shell Sb2S3/Sb@TiO2@C nanorod composite has been designed layer by layer, which includes an inner Sb2S3/Sb heterostructure core protected by an oxygen-deficient TiO2 shell and a conductive carbon shell. It is interesting to observe that, during the carbothermic reduction process, the previous Sb2S3 nanorod cores are partially reduced into a metallic Sb phase and the reduced TiO2 also creates many oxygen vacancies, which can greatly enhance the conductivity of the semiconductor Sb2S3. Thanks to the double effects of the TiO2 middle shell and carbon outer shell, the unique double-shelled structure design creates an enhanced dual protection, which can better accommodate the volume-expansive deformation and preserve the structural integrity of the active Sb2S3/Sb core. Especially, the TiO2 middle layer is self-assembled by numerous nanoparticles acting as a nanopillar backbone, which supports between the nanorod core and outer carbon shell to better buffer the volume changes. As a result, the core-shell-shell Sb2S3/Sb@TiO2@C anode shows lithium and sodium storage performances superior to those of the pristine Sb2S3 and core-shell Sb2S3@TiO2 electrodes. For lithium-ion batteries, the Sb2S3/Sb@TiO2@C nanorod composite achieves an initial discharge/recharge capacity of 1244.9/1005.1 mAh g-1 with an initial Coulombic efficiency of about 80.7%, an enhanced rate capability with a capacity of 593.2 mA h g-1 at 5.0 A g-1, and prolonged cycling life for 500 cycles with a reversible capacity of 495.8 mAh g-1 at 0.5 A g-1. For sodium-ion batteries, the nanorodalso exhibits an improved performance with an initial discharge/recharge capacity of 781.4/574.0 mAh g-1 (initial Coulombic efficiency of about 73.46%) and cycling for 400 cycles with a reversible capacity of 422.6 mAh g-1 at 0.8 A g-1. This research sheds light upon double-shell structure designs with an effective middle shell to enhance the energy storage performance of electrode materials.

MoS2 nanosheets vertically grown on CoSe2 hollow nanotube arrays as an efficient catalyst for the hydrogen evolution reaction.

Although the design and synthesis of efficient electrocatalysts for the hydrogen evolution reaction (HER) are highly desirable, severe challenges still need to be addressed. Herein, ultrathin MoS2 nanosheets were vertically grown on CoSe2 hollow nanotube arrays via a simple three-step hydrothermal reaction by using carbon cloth (CC) as a substrate and were subsequently used as a highly efficient HER electrocatalyst (MoS2@CoSe2-CC hybrid). The MoS2 nanosheets uniformly self-assembled on conductive CoSe2 nanotube arrays exhibited a hierarchical and well-ordered structure. Such a unique structure may not only comprise more exposed active sites, but also enable fast electrolyte penetration and facilitate H+/electron transportation to accelerate the reduction and evolution of H2 during the electrocatalytic process. As an HER electrocatalyst with a novel three-dimensional hierarchical structure, the MoS2@CoSe2-CC hybrid exhibited an outstanding catalytic HER performance with a small Tafel slope of 67 mV dec-1 in alkaline media, while only requiring a low HER overpotential of 101 mV at 10 mA cm-2. Notably, the MoS2@CoSe2-CC hybrid also demonstrated exceptional electrochemical durability and structural stability even after 1000 cycles or 48 h of continuous electrolysis. Overall, this work presents a new approach for the design and synthesis of robust, highly active, and cost-effective electrocatalysts for hydrogen generation.

Rechargeable Aqueous Zinc-Ion Batteries in MgSO4/ZnSO4 Hybrid Electrolytes.

MgSO4 is chosen as an additive to address the capacity fading issue in the rechargeable zinc-ion battery system of MgxV2O5·nH2O//ZnSO4//zinc. Electrolytes with different concentration ratios of ZnSO4 and MgSO4 are investigated. The batteries measured in the 1 M ZnSO4-1 M MgSO4 electrolyte outplay other competitors, which deliver a high specific capacity of 374 mAh g-1 at a current density of 100 mA g-1 and exhibit a competitive rate performance with the reversible capacity of 175 mAh g-1 at 5 A g-1. This study provides a promising route to improve the performance of vanadium-based cathodes for aqueous zinc-ion batteries with electrolyte optimization in cost-effective electrolytes.

Efficient Sodium Storage in Rolled-Up Amorphous Si Nanomembranes.

Alloying-type materials are promising anodes for high-performance sodium-ion batteries (SIBs) because of their high capacities and low Na-ion insertion potentials. However, the typical candidates, such as P, Sn, Sb, and Pb, suffer from severe volume changes (≈293-487%) during the electrochemical reactions, leading to inferior cycling performances. Here, a high-rate and ultrastable alloying-type anode based on the rolled-up amorphous Si nanomembranes is demonstrated. The rolled-up amorphous Si nanomembranes show a very small volume change during the sodiation/desodiation processes and deliver an excellent rate capability and ultralong cycle life up to 2000 cycles with 85% capacity retention. The structural evolution and pseudocapacitance contribution are investigated by using the ex situ characterization techniques combined with kinetics analysis. Furthermore, the mechanism of efficient sodium-ion storage in amorphous Si is kinetically analyzed through an illustrative atomic structure with dangling bonds, offering a new perspective on understanding the sodium storage behavior. These results suggest that nanostructured amorphous Si is a promising anode material for high-performance SIBs.

[Association of MnSOD single nucleotide polymorphism with the occurrence and clinical outcome of nasopharyngeal carcinoma in Cantonese].

OBJECTIVE: To evaluate the association of MnSOD single nucleotide polymorphisms (SNPs) with the susceptibility to nasopharyngeal carcinoma (NPC) in Cantonese. METHODS: A total of 105 Cantonese NPC patients and 136 age-matched healthy controls were enrolled in this study. Genotyping of the SNP Ala-9Val of MnSOD gene was performed by PCR and direct sequencing of the PCR products. RESULTS: The allele frequency of Ala in Cantonese was 19.1%. The frequencies of Val/Val, Val/Ala, and Ala/Ala genotypes were 83.8%, 14.3%, and 1.9% in NPC patients and 80.9%, 16.9%, and 2.2% in healthy individuals, respectively. No significant differences were found in the allele or genotype frequencies between NPC patients and controls. Ala/Val genotype was shown to be significantly less frequent in patients with a positive lymph node status, but the allele Ala was not correlated to lymph node involvement. No significant differences were found in the allele and genotype frequencies in patients with different tumor sizes, metastatic statuses, clinical statuses and histological types. CONCLUSION: MnSOD Ala-9Val polymorphism can be region- and race-related, and it is not correlated to the genetic susceptibility of NPC in Cantonese.