Ultrafine Co1-xS Attached to Porous Interconnected Carbon Skeleton for Sodium-Ion Batteries

Organic polymer coating induced multiple heteroatom-doped carbon framework confined Co1-xS@NPSC core-shell hexapod for advanced sodium/potassium ion batteries

Synthesis of advanced structure and multiple heteroatom-doped carbon based heterostructure materials are the key to the preparation of high-performance energy storage electrode materials. Herein, the hexapod-shaped Co1-xS@NPSC has been triumphantly prepared using hexapod ZIF-67 as the sacrificial template to prepare Co1-xS inner core and N, P, and S tri-doped carbon (NPSC) as the shell through the carbonization of the organic polymer precursor. When applied as anode for Na+ batteries (SIBs) and K+ batteries (PIBs), Co1-xS@NPSC presents the high reversible specific capability of 747.4 mAh/g at 1.0 A/g after 235 cycles and 387.8 mAh/g at 5.0 A/g after 760 cycles for SIBs, as well as 326.7 mAh/g at 1.0 A/g after 180 cycles for PIBs. The excellent storage capacity and rate capability of Co1-xS@NPSC is ascribed to hexapod structure of ZIF-67 unlike the common dodecahedron, which is constructed with interior porous and exterior framework repository, donating supplemental active sites, and doping of multiple heteroatoms forming organic polymer coating inhibiting the volume expansion and restrains the agglomeration of Co1-xS nanoparticles. This approach has paved a bright avenue to exploit promising anode materials with novel structure and hetero-atom doping for high-performance energy storage devices.

Optimized Fabrication of Bimetallic ZnCo Metal-Organic Framework at NiCo-Layered Double Hydroxides for Multiple Storage and Capability Synergy All-Solid-State Supercapacitors

Rational design and structural regulation of hybrid nanomaterials with superior electrochemical performance are crucial for developing sustainable energy storage platforms. Among these materials, NiCo-layered double hydroxides (NiCo-LDHs) demonstrate an exceptional charge storage capabilities owing to their tunable 2D lamellar structure, large interlayer spacing, and rich redox electrochemically active sites. However, NiCo-LDHs still suffer from sever agglomeration of their particles with limited charge transfer rates, resulting in an inadequate rate capability. In this study, bimetallic ZnCo-metal organic framework (MOF) tripods were grown on the surface of NiCo-LDH nanowires, which significantly reduced the self-agglomeration and stacking of the NiCo-LDH nanowire arrays, offering more accessible active sites for charge transfer and shortening the path for ion diffusion. The fabricated hybrid ZnCo-MOF@NiCo-LDH and its individual counterparts were tested as supercapacitor electrodes. The ZnCo-MOF@NiCo-LDH electrode demonstrated a remarkable specific capacitance of 1611 F g^-1 at 2 A g^-1 with an enhanced rate capability of 66% from 2 to 20 A g^-1. Moreover, an asymmetric all solid-state supercapacitor device was constructed using ZnCo-MOF@NiCo-LDH and palm tree-derived activated carbon (P-AC) as positive and negative poles, respectively. The constructed device can store a high specific energy of 44.5 Wh Kg^-1 and deliver a specific power of 876.7 W Kg^-1 with outstanding Columbic efficiency over 10,000 charging/discharging cycles at 15 A g^-1.

Synthesis of Nanostructured Bismuth Sulfide with Controllable Morphology for Advanced Lithium/Sodium-Ion Storage

Rational design of electrode materials with an excellent structure and morphology is crucial for improving electrochemical properties. Herein, various unique nanostructured Bi₂S₃ materials with controllable morphology were obtained through a simple and efficient oil bath reaction strategy. Bi₂S₃ with different morphologies can be obtained by regulating the polarity of solvent, and the lattice spacing can also be adjusted. The Bi₂S₃ nanomaterials obtained with ethanol as solvent (BS-3) show a three-dimensional nanoflower-like structure assembled with porous layers. The unique structure facilitates the transport of ions and accommodates the volume variation of Bi₂S₃ during energy storage. Consequently, BS-3 nanoflowers exhibited superior cycling stability and excellent high-rate capability for lithium storage (maintained a high capacity of 923.8 mA h g^-1 after 950 cycles at 1.0 A g^-1) and excellent sodium storage. We provide guidance for precise synthesis and energy storage application of Bi₂S₃ nanomaterials.

Investigation of the Sn4+-distribution and photocatalytic performance of Sn4+/TiO2 hollow fiber nanomaterials

Tin ion-doped TiO2 fibers were smartly prepared, and the distribution depth of Sn4+ influences the photocatalytic performance of TiO2.

Co-Salen Complex-Derived CoP Nanoparticles Confined in N-Doped Carbon Microspheres for Stable Sodium Storage

The poor rate and cycle performance rooting from the inferior electrical conductivity and large volume change are bottlenecks for further application of the potential anode material in sodium-ion batteries. To address this problem, homogeneous CoP nanoparticles enwrapped in the N-doped carbon (CoP/NC) microspheres are synthesized by the simultaneous carbonization and phosphorization of Co-salen complex microspheres for the first time. The N-doped carbon enhances its conductivity and diminishes the volume stress, and the dispersed CoP nanoparticles in carbon provide more reaction sites, resulting in a superior sodium storage performance. CoP/NC microspheres exhibit the capacity of 373 mA h g^-1 at 0.1 A g^-1 after 100 cycles. Even at 2 A g^-1 for 2000 cycles, the capacity of 195 mA h g^-1 is also achieved. This work provides an excellent reference for the design and synthesis of sulfide, selenide, and other transition-metal composites. It is also beneficial to expand the application of salen complexes in the design and synthesis of catalysts and energy storage materials.

NiCo2S4 Nanocrystals on Nitrogen-Doped Carbon Nanotubes as High-Performance Anode for Lithium-Ion Batteries

In recent years, the development of lithium-ion batteries (LIBs) with high energy density has become one of the important research directions to fulfill the needs of electric vehicles and smart grid technologies. Nowadays, traditional LIBs have reached their limits in terms of capacity, cycle life, and stability, necessitating their further improvement and development of alternative materials with remarkably enhanced properties. A nitrogen-containing carbon nanotube (N-CNT) host for bimetallic sulfide (NiCo₂S₄) is proposed in this study as an anode with attractive electrochemical performance for LIBs. The prepared NiCo₂S₄/N-CNT nanocomposite exhibited improved cycling stability, rate performance, and an excellent reversible capacity of 623.0 mAh g^-1 after 100 cycles at 0.1 A g^-1 and maintained a high capacity and cycling stability at 0.5 A g^-1. The excellent electrochemical performance of the composite can be attributed to the unique porous structure, which can effectively enhance the diffusivity of Li ions while mitigating the volume expansion during the charge-discharge processes.

Co-Vacancy, Co1−xS@C flower-like nanosheets derived from MOFs for high current density cycle performance and stable sodium-ion storage

A non-stoichiometric cobalt–sulfur compound anode material with excellent electrochemical properties was prepared, and the first principles simulation described the effect of Co-vacancy on electrode reaction.

MoS2 encapsulated in three-dimensional hollow carbon frameworks for stable anode of sodium ion batteries

MoS₂ wrapped in nitrogen-doped three-dimensional hollow carbon frameworks is designed for improved sodium ion battery anode performance.

Spongy p-Toluenesulfonic Acid-doped Polypyrrole with Extraordinary Rate Performance as Durable Anodes of Sodium-Ion Batteries at Different Temperatures

Sodium-ion batteries (SIBs) have potential as an energy storage system because they have similar electrochemical properties as lithium-ion batteries, abundant resource reserves, and extremely high safety performance. Compared with traditional graphite materials, conductive polymers are more suitable as an anode electrode material for SIBs. In this study, a simple and scalable approach has been used to synthesize p-toluenesulfonic acid-doped polypyrrole (p-TSA-PPy). The as-obtained material showed remarkable rate capacities and cyclability. At room temperature (25 °C), its discharge capacities could reach 185, 162, and 135 mAh g^-1 under 10, 30, and 50 C rates after 250 cycles, respectively. More importantly, the capacity of the p-TSA-PPy could still be maintained at 120.5 mAh g^-1 even at the 2000th cycle at 10 C. In addition, it achieves attractive electrochemical performance at different temperatures (0 and 50 °C).