Codon usage bias and genetic diversity in chloroplast genomes of Elaeagnus species (Myrtiflorae: Elaeagnaceae).

Codon usage bias (CUB) reveals the characteristics of species and can be utilized to understand their evolutionary relationship, increase the target genes' expression in the heterologous receptor plants, and further provide theoretic assistance for correlative study on molecular biology and genetic breeding. The chief aim of this work was to analyze the CUB in chloroplast (cp.) genes in nine Elaeagnus species to provide references for subsequent studies. The codons of Elaeagnus cp. genes preferred to end with A/T bases rather than with G/C bases. Most of the cp. genes were prone to mutation, while the rps7 genes were identical in sequences. Natural selection was inferred to have a powerful impact on the CUB in Elaeagnus cp. genomes, and their CUB was extremely strong. In addition, the optimal codons were identified in the nine cp. genomes based on the relative synonymous codon usage (RSCU) values, and the optimal codon numbers were between 15 and 19. The clustering analyses based on RSCU were contrasted with the maximum likelihood (ML)-based phylogenetic tree derived from coding sequences, suggesting that the t-distributed Stochastic Neighbor Embedding clustering method was more appropriate for evolutionary relationship analysis than the complete linkage method. Moreover, the ML-based phylogenetic tree based on the conservative matK genes and the whole cp. genomes had visible differences, indicating that the sequences of specific cp. genes were profoundly affected by their surroundings. Following the clustering analysis, Arabidopsis thaliana was considered the optimal heterologous expression receptor plant for the Elaeagnus cp. genes. Supplementary Information: The online version contains supplementary material available at 10.1007/s12298-023-01289-6.

CuSe2 Nanocubes Enabling Efficient Sodium Storage.

As the most promising candidate for lithium-ion batteries (LIBs), the electrochemical performance of sodium-ion batteries (SIBs) is highly dependent on the electrode materials. Copper selenides have established themselves as potential anode materials for SIBs due to their high theoretical capacity and good conductivity. However, the poor rate performance and fast capacity fading are the major challenges to their practical application in SIBs. Herein, single-crystalline CuSe2 nanocubes (CuSe2 NCs) are successfully synthesized via a solvothermal method. As an anode of SIBs, the CuSe2 NCs render an almost 100% initial Coulombic efficiency, an outstanding long cycle life, e.g., 380 mA h g-1 after 1700 cycles at 10 A g-1, and an unprecedented rate performance of 344 mA h g-1 at 50 A g-1. Ex situ X-ray diffraction (XRD) patterns reveal the crystalline transformation of energy-storage materials, and the density functional theory (DFT) conclusion suggests that fast and stable ion diffusion kinetics enhances their electrochemical performance upon sodiation/desodiaton. The investigation into the mechanism provides a theoretical basis for subsequent practical applications.

2D Bismuth@N-Doped Carbon Sheets for Ultrahigh Rate and Stable Potassium Storage.

Metallic Bi, as an alloying-type anode material, has demonstrated tremendous potential for practical application of potassium-ion batteries. However, the giant volume expansion, severe structure pulverization, and sluggish dynamics of Bi-based materials result in unsatisfied rate performance and unstable cycling stability. Here, 2D bismuth@N-doped carbon sheets with BiOC bond and internal void space (2D Bi@NOC) are successfully fabricated via a self-template strategy to address these issues, which own ultrafast electrochemical kinetics and impressive long-term cycling stability for delivering an admirable capacity of 341.7 mAh g-1 after 1000 cycles at 10 A g-1 and impressive rate capability of 220.6 mAh g-1 at 50 A g-1 . Particularly, the in situ transmission electron microscopy observations visualize the real-time alloying/dealloying process and reveal that plastic carbon shell and void space can availably relieve dramatic volume stress and powerfully maintain structural integrity. Density functional theory calculation and ultraviolet photoelectron spectroscopy test certify that the robust BiOC bond is thermodynamically and kinetically beneficial for adsorption/diffusion of K+ . This work will light on designing advanced high-performance energy materials and provide important evidence for understanding the energy storage mechanism of alloy-based materials.

Confining MoSe2 Nanosheets into N-Doped Hollow Porous Carbon Microspheres for Fast-Charged and Long-Life Potassium-Ion Storage.

The potassium-ion battery (PIB) is the most promising alternative to a lithium-ion battery (LIB). Exploitation of a suitable electrode material is crucial to promote the development of PIBs. The MoSe2 material has attracted much attention due to its high theoretical capacity, unique layered structure, and good conductivity. However, the potassium storage property of MoSe2 has been suffering from structural fragmentation and sluggish reaction kinetic caused by large potassium ions upon insertion/extraction, which needs to be further improved. Herein, the MoSe2 nanosheets are confined into N-doped hollow porous carbon microspheres (MoSe2@N-HCS) by spray drying and high-temperature selenization. It delivers a superior rate performance of 113.7 mAh g-1 at 10 A g-1 and remains at a high capacity of 158.3 mAh g-1 at 2 A g-1 even after 16 700 cycles for PIBs. The excellent electrochemical performance can be attributed to unique structure, N-doping, and robust chemical bonds. The storage mechanism of MoSe2 for potassium ions was explored. The outstanding properties of MoSe2@N-HCS make it a promising anode material for PIBs.

Alloyed BiSb Nanoparticles Confined in Tremella-Like Carbon Microspheres for Ultralong-Life Potassium Ion Batteries.

Bismuth-antimony alloy is considered as a promising potassium ion battery anode because of its combination of the high theoretical capacity of antimony and the excellent rate capacity of bismuth. However, the large volume change and sluggish reaction kinetic upon cycling have triggered severe capacity fading and poor rate performance. Herein, a nanoconfined BiSb in tremella-like carbon microspheres (BiSb@TCS) are delicately designed to address these issues. As-prepared BiSb@TCS renders an outstanding potassium-storage performance with a reversible capacity of 181 mAh g-1 after ultralong 5700 cycles at a current density of 2 A g-1 , and an excellent rate capacity of 119.3 mAh g-1 at 6 A g-1 . Such a superior performance can be ascribed to the delicate microstructure. The self-assembled carbon microspheres can strengthen integral structure and effectively accommodate the volume expansion of BiSb nanoparticles, and 2D carbon nanowalls in carbon microspheres can provide fast ion/electron diffusion dynamic. Theoretical calculation also suggests a thermodynamic feasibility of alloyed BiSb nanoparticles for storing potassium ion. Such a work shows that BiSb@TCS possesses a great potential to be a high-performance anode of potassium ion batteries. The rational designing of multiscaled structure would be instructive to the exploitation of other energy-storage materials.

Self-Formed Channel Boosts Ultrafast Lithium Ion Storage in Fe3O4@Nitrogen-Doped Carbon Nanocapsule.

Investigations into conversion-type materials such as transition-metal oxides have dominated in energy-storage systems, especially for lithium ion batteries in recent years. A common understanding of taking account of high energy density and high power density allows us to design reasonable electrodes. In this study, the unique Fe3O4@nitrogen-doped carbon (denoted as Fe3O4@NC) nanocapsule with self-formed channels was synthesized based on a facile hydrothermal-coating-annealing route. With respect to the effect of this rational architecture on lithium-storage performance, excellent behavior (a high reversible capacity of 480 mAh g-1) could be maintained at 20 A g-1 during 1000 cycles, with an average Coulombic efficiency of 99.97%. It also means that such a Fe3O4@NC electrode can meet a fast-charge challenge (end-of-charge within ∼2 min). By a series of investigations, we certainly considered that uniform carbon coating improved electrical conductivity and acted as a buffer layer to accommodate volume variations of Fe3O4 nanoparticles during cycling. It is more interesting that self-formed channels can effectively shorten the ion diffusion path and provide a necessary space to buffer volume expansion as well. Benefiting from these synergetic advantages, this Fe3O4@NC nanocapsule also delivered outstanding electrochemical performances in full cells.

Ultrahigh Rate Performance of Hollow Antimony Nanoparticles Impregnated in Open Carbon Boxes for Sodium-Ion Battery under Elevated Temperature.

Antimony is a competitive and promising anode material for sodium-ion batteries (SIBs) due to its high theoretical capacity. However, the poor rate capability and fast capacity fading greatly restrict its practical application. To address the above issues, a facile and eco-friendly sacrificial template method is developed to synthesize hollow Sb nanoparticles impregnated in open carbon boxes (Sb HPs@OCB). The as-obtained Sb HPs@OCB composite exhibits excellent sodium storage properties even when operated at an elevated temperature of 50 °C, delivering a robust rate capability of 345 mAh g-1 at 16 A g-1 and rendering an outstanding reversible capacity of 187 mAh g-1 at a high rate of 10 A g-1 after 300 cycles. Such superior electrochemical performance of the Sb HPs@OCB can be attributed to the comprehensive characteristics of improved kinetics derived from hollow Sb nanoparticles impregnated into 2D carbon nanowalls, the existence of robust SbOC bond, and enhanced pseudocapacitive behavior. All those factors enable Sb HPs@OCB great potential and distinct merit for large-scale energy storage of SIBs.

Resilient Energy Storage under High-Temperature with In-Situ-Synthesized MnOx@Graphene as Anode.

An novel exfoliation strategy to few-layered graphene (FLG) combined with in situ synthesized amorphous MnOx has been established via a facile and robust ball milling route in the presence of KMnO4. The facile synthesis approach has the features of low cost, environmentally friendly nature and scalable capability. As an anode for lithium-ion batteries, amorphous MnOx@FLG delivered a wonderful electrochemical performance under extremely operational conditions, that is, an excellent reversible capacity of 856 mAh g-1 at a high current density of 1 A g-1 after 75 cycles under a high temperature of 85 °C. Those excellent electrochemical performances could be ascribed to elaborately designed three-dimensional nanostructure, the well-chosen electrolyte, significant incorporation of in situ Mn(IV) nanocrystal and few-layered graphene, and the contribution of pseudocapacitance. Remarkable electrochemical performance under a widely operational temperature window makes the amorphous MnOx@FLG composites promising anode of Li-ion batteries for heavy-duty application.

Germanium-Based Nanomaterials for Rechargeable Batteries.

Germanium-based nanomaterials have emerged as important candidates for next-generation energy-storage devices owing to their unique chemical and physical properties. In this Review, we provide a review of the current state-of-the-art in germanium-based materials design, synthesis, processing, and application in battery technology. The most recent advances in the area of Ge-based nanocomposite electrode materials and electrolytes for solid-state batteries are summarized. The limitations of Ge-based materials for energy-storage applications are discussed, and potential research directions are also presented with an emphasis on commercial products and theoretical investigations.

Correction: Core-shell Zn2GeO4 nanorods and their size-dependent photoluminescence properties.

Correction for 'Core-shell Zn2GeO4 nanorods and their size-dependent photoluminescence properties' by Songping Wu et al., Nanoscale, 2013, 5, 12335-12341.

CuGeO3 nanowires covered with graphene as anode materials of lithium ion batteries with enhanced reversible capacity and cyclic performance.

A facile one-step route was developed to synthesize crystalline CuGeO3 nanowire/graphene composites (CGCs). Crystalline CuGeO3 nanowires were tightly covered and anchored by graphene sheets, forming a layered structure. Subsequently, CGCs were exploited as electrode materials for lithium ion batteries (LIBs). The reversible formation of Li2O buffer layer and elastic graphene sheets accommodated the volume change during the charge and discharge processes. CGC containing 37 wt% graphene exhibited a superior electrochemical performance, that is, a remarkable reversible capacity (1265 mA h g(-1) for the first cycle), an outstanding cyclic performance (853 mA h g(-1) after 50 cycles under a current density of 200 mA g(-1)), a high coulombic efficiency, and an excellent rate capability. Clearly, CGCs may stand out as a promising anode material for LIBs.

Partially crystalline Zn2GeO4 nanorod/graphene composites as anode materials for high performance lithium ion batteries.

Zn2GeO4 nanorod/graphene composites (ZGCs) were yielded by a two-step hydrothermal processing. Crystalline and amorphous regions were found to coexist in a single Zn2GeO4 nanorod. The surface of the Zn2GeO4 nanorod was compactly covered and anchored by graphene sheets. The ZGCs were then utilized as anodes for lithium ion batteries (LIBs). Intriguingly, partially crystalline ZGC containing 10.2 wt % graphene possessed excellent electrochemical performance, namely, high reversible capacity (1020 mA h g(-1) in the first cycle), favorable cyclic performance (768 mA h g(-1) after 50 cycles), and commendable rate capability (780 mA h g(-1) at the current density of 0.8A g(-1)). The amorphous region in partially crystalline Zn2GeO4 nanorods and the elastic graphene sheets provided the accommodation of volume change during the charge and discharge processes. These advantageous attributes make ZGCs the potential anode materials for LIBs.

Core-shell Zn2GeO4 nanorods and their size-dependent photoluminescence properties.

Size-tunable crystalline core-crystalline shell Zn2GeO4 nanorods were synthesized via a facile hydrothermal reaction. High purity Zn2GeO4 nanorods were obtained at pH = 7. The length of Zn2GeO4 nanorods (L = 50-100 nm) can be controlled through a one-step process, while micro-sized nanorods with an aspect ratio of the length to the diameter of 10 were yielded in a two-step process. The single crystalline nature of Zn2GeO4 nanorods with a core-shell structure was verified by high resolution transmission electron microscopy (HRTEM) and selected area electron diffraction (SAED) measurements. The Raman study revealed that there is no oxygen defect in Zn2GeO4 nanocrystals, suggesting that photoluminescence emission of Zn2GeO4 can be attributed to the presence of the interstitial Zn defect in Zn2GeO4 nanocrystals. As the diameter of nanorods decreased, the excitation and emission peaks appeared to be redshifted due to the quantum size effect.

Heterobimetallic peroxo-titanium(IV) nitrilotriacetate complexes as single source precursors for preparation of MTiO3 (M = Co, Ni and Zn).

Three isostructural heterobimetallic nitrilotriacetatoperoxotitanate complexes of general formula [M(H(2)O)(5)](2)[Ti(2)(O(2))(2)O(nta)(2)].7H(2)O [M = Co (1), Ni (2) and Zn (3)] have been isolated in pure crystals directly from the quaternary system of M(2+)-Ti(OC(4)H(9))(4)-H(2)O(2)-H(3)nta (H(3)nta = nitrilotriacetic acid) at pH = 4.0 and have been characterized by elemental analyses, IR, thermal analysis (TGA), and single-crystal X-ray diffraction. Single crystal X-ray analysis reveals that the titanium atom in these complexes features seven-fold-coordination, each surrounded by six oxygen atoms and one nitrogen atom. The divalent transition metal ions in these compounds are hexa coordinated, surrounded by five water molecules and one bridged carboxylato oxygen atom. The TGA and XRD results prove that complexes 1-3 undergo facile thermal decomposition to form pure CoTiO(3), NiTiO(3) and ZnTiO(3) at 700 degrees C respectively. The morphologies, microstructures, and crystallinity of the residues obtained after pyrolysis were characterized by transmission electron microscopy and powder X-ray diffraction.