The first synthesis of MnO@Mn O nanoparticles embedded in an N-doped porous carbon framework (MnO@Mn O /NPCF) through pyrolysis of mixed-valent Mn clusters is reported. The unique features of MnO@Mn O /NPCF are derived from the distinct interfacial structure of the Mn clusters, implying a new methodological strategy for hybrids. The characteristics of MnO@Mn O are determined by conducting high angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) and electron energy loss spectroscopy (EELS) valence-state analyses. Due to the combined advantages of MnO@Mn O , the uniform distribution, and the NPCF, MnO@Mn O /NPCF displays unprecedented lithium-storage performance (1500 mA h g at 0.2 A g over 270 cycles). Quantitative analysis reveals that capacitance and diffusion mechanisms account for Li storage, wherein the former dominates. First-principles calculations highlight the strong affiliation of MnO@Mn O and the NPCF, which favor structural stability. Meanwhile, defects of the NPCF decrease the diffusion energy barrier, thus enhancing the Li pseudocapacitive process, reversible capacity, and long cycling performance. This work presents a new methodology to construct composites for energy storage and conversion.

Sodium-ion batteries (SIBs) are considered promising next-generation energy storage devices. However, a lack of appropriate high-performance anode materials has prevented further improvements. Here, a hierarchical porous hybrid nanosheet composed of interconnected uniform TiO nanoparticles and nitrogen-doped graphene layer networks (TiO @NFG HPHNSs) that are synthesized using dual-functional C N nanosheets as both the self-sacrificing template and hybrid carbon source is reported. These HPHNSs deliver high reversible capacities of 146 mA h g at 5 C for 8000 cycles, 129 mA h g at 10 C for 20 000 cycles, and 116 mA h g at 20 C for 10 000 cycles, as well as an ultrahigh rate capability up to 60 C with a capacity of 101 mA h g . These results demonstrate the longest cyclabilities and best rate capability ever reported for TiO -based anode materials for SIBs. The unprecedented sodium storage performance of the TiO @NFG HPHNSs is due to their unique composition and hierarchical porous 2D structure.

Vanadium-based compounds with an open framework structure have become the subject of much recent investigation into aqueous zinc-ion batteries (AZIBs) due to high specific capacity. However, there are some issues with vanadium dissolution from a cathode framework as well as the generation of byproducts during discharge that should not be ignored, which could cause severe capacity deterioration and inadequate cycle life. Herein, we report several barium vanadate nanobelt cathodes constructed of two sorts of architectures, i.e., Ba 1., which are controllably synthesized by tuning the amount of barium precursor. Benefiting from the robust architecture, layered Ba x V 3 O 8 -type nanobelts (Ba 1.2 V 6 O 16 •3H 2 O) exhibit superior rate capability and long-term cyclability owing to fast zinc-ion kinetics, enabled by efficiently suppressing cathode dissolution as well as greatly eliminating the generation of byproduct Zn 4 SO 4 (OH) 6 •xH 2 O, which provides a reasonable strategy to engineer cathode materials with robust architectures to improve the electrochemical performance of AZIBs.

Lithium‐sulfur batteries (LSBs) have been regarded as a competitive candidate for next‐generation electrochemical energy‐storage technologies due to their merits in energy density. The sluggish redox kinetics of the electrochemistry and the high solubility of polysulfides during cycling result in insufficient sulfur utilization, severe polarization, and poor cyclic stability. Herein, sulfiphilic few‐layered MoSe2 nanoflakes decorated rGO (MoSe2@rGO) hybrid has been synthesized through a facile hydrothermal method and for the first time, is used as a conceptually new‐style sulfur host for LSBs. Specifically, MoSe2@rGO not only strongly interacts with polysulfides but also dynamically strengthens polysulfide redox reactions. The polarization problem is effectively alleviated by relying on the sulfiphilic MoSe2. Moreover, MoSe2@rGO is demonstrated to be beneficial for the fast nucleation and uniform deposition of Li2S, contributing to the high discharge capacity and good cyclic stability. A high initial capacity of 1608 mAh g−1 at 0.1 C, a slow decay rate of 0.042% per loop at 0.25 C, and a high reversible capacity of 870 mAh g−1 with areal sulfur loading of 4.2 mg cm−2 at 0.3 C are obtained. The concept of introducing sulfiphilic transition‐metal selenides into the LSBs system can stimulate engineering of novel architectures with enhanced properties for various energy‐storage devices.

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Well-distributed graphene sheets doped with nitrogen (NGS) were prepared via a thermal annealing strategy with the existence of cyanamide. The cyanamide can efficiently restrain the conglomeration of the resultant graphene sheets and synchronously make sure the doping of nitrogen. Followed by the next-step of low-temperature solvothermal route, uniform ultrasmall tin sulfide (SnS 2 ) nanocrystals were readily grown on the preformed NGS (denoted as SnS 2 -NGS).Benefiting from the synergistic function between NGS and SnS 2 , the resultant composites exhibit excellent electrochemical performance. In case of estimation as anode materials for lithium-ion batteries (LIBs), SnS 2 -NGS with moderate weight ratio of SnS 2 deliver outstanding electrochemical outcomes giving the high reversible capacity of 1407 mA h g -1 at 200 mA g -1 after 120 cycles. The composites can also maintain a reversible capacity of about 200 mA h g -1 at a high current density of 10 A g -1 . The lithium-ion storage ability of prepared SnS 2 -NGS electrode is at the top rank in comparison with the other works. The obtained composites also achieve good sodium storage ability.

sources. [1][2][3] To satisfy the requirements of upcoming large-scale energy storage applications, it is highly urgent to develop high-energy-density LIBs by elegantly configuring advanced electrode materials. The present commercial graphite anodes have a low theoretical capacity of 372 mA h g −1 , approaching the lithium storage limit. [4][5][6] Transition-metal oxides (TMOs) outperform graphite as anode alternatives, mechanistically operating through conversion reactions. [1] Notably, cobalt oxides (CoO or Co 3 O 4 ) can theoretically deliver as much as two to three times the specific capacity of graphite due to their multielectron conversion reaction upon electrochemical cycling. [5][6][7] However, the undesired volume expansion of cobalt oxides leads to the destruction of electrodes, accompanied by rapid capacity fading during repeated lithium ion insertion/extraction processes; additionally, their poor electrical conductivity causes weak rate capability. [8,9] Therefore, the lithium storage performance of materials that include cobalt oxides requires optimization of their composition and structure through engineering to achieve lithium storage performance suitable for practical applications. [4,[10][11][12] To this end, one of the most effective strategies is confining or embedding TMOs into a carbonaceous matrix to form hybrids, which can accommodate large volume changes, improve electrical conductivity, and maintain the integrity of the electrode. Generally, the sources of TMOs and carbon are separate, and the carbonization proceeds via a gas-solid reaction. However, another strategy wherein a single precursor was pyrolyzed to simultaneously generate the two components was also efficacious to create these hybrids. This method exhibits advantages including nanosized TMO particles and a highsurface-area carbon matrix. Despite recent advances, the search for suitable precursors for advantageous novel hybrid materials with enhanced performance remains challenging.Metal-organic frameworks (MOFs) are highly ordered crystalline polymers with tailorable voids constructed by the coordination of metal ions or polynuclear clusters with polytopic organic ligands. They serve as precursors for facile transformation into hybrid structures including composites of metal oxides/carbon, metal phosphides/carbon, or metal sulfides/carbon after thermal treatment under appropriate atmospheres. [13][14][15][16][17][18] As a Despite great breakthroughs, the search for anode materials with high performance for lithium-ion batteries (LIBs) remains challenging. Hence, engineering advantageous structures via effective routes can bring new possibilities to the development of the LIB field. Herein, the precise synthesis of three-dimensional (3D) hybrids of ultrathin carbon-wrapped CoO (CoO@C) dandelions is reported by the pyrolysis of two-dimensional (2D) Kagóme metal-organic layers (MOLs) at 400 °C under an Ar atmosphere. Due to the special coordination structure of the paternal MOLs, the resulting CoO nanowires show a small diameter ...

Rechargeable aqueous zinc-ion batteries have shown great potential for grid-scale applications owing to their high safety, low cost and sustainability.