Graphene-Embedded Co₃O₄ Rose-Spheres for Enhanced Performance in Lithium Ion Batteries

Co₃O₄ has been widely studied as a promising candidate as an anode material for lithium ion batteries. However, the huge volume change and structural strain associated with the Li⁺ insertion and extraction process leads to the pulverization and deterioration of the electrode, resulting in a poor performance in lithium ion batteries. In this paper, Co₃O₄ rose-spheres obtained via hydrothermal technique are successfully embedded in graphene through an electrostatic self-assembly process. Graphene-embedded Co₃O₄ rose-spheres (G-Co₃O₄) show a high reversible capacity, a good cyclic performance, and an excellent rate capability, e.g., a stable capacity of 1110.8 mAh g^–1 at 90 mA g^–1 (0.1 C), and a reversible capacity of 462.3 mAh g^–1 at 1800 mA g^–1 (2 C), benefitted from the novel architecture of graphene-embedded Co₃O₄ rose-spheres. This work has demonstrated a feasible strategy to improve the performance of Co₃O₄ for lithium-ion battery application

Facile Synthesis of ZnS/N,S Co-doped Carbon Composite from Zinc Metal Complex for High-Performance Sodium-Ion Batteries

ZnS coated on N,S co-doped carbon (ZnS/NSC) composite has been prepared utilizing zinc pyrithione (C₁₀H₈N₂O₂S₂Zn) as raw material via calcination. Through activation using Na₂CO₃ salt, ZnS nanoparticles encapsulated in NSC (denoted as A-ZnS/NSC) with mixed-crystal structure has also been obtained, which reveals much larger specific surface area and more bridges between ZnS and NSC. Based on the existence of bridges (C–S–Zn and S–O–Zn bonds) and the modification of carbon from N,S co-doping, the A-ZnS/NSC composite as an anode for sodium-ion batteries (SIBs) displays significantly enhanced electrochemical performances with a high reversible specific capacity of 516.6 mA h g^–1 (at 100 mA g^–1), outstanding cycling stability (96.9% capacity retention after 100 cycles at 100 mA g^–1), and high rate behavior (364.9 mA h g^–1 even at 800 mA g^–1)

Edge-Rich Quasi-Mesoporous Nitrogen-Doped Carbon Framework Derived from Palm Tree Bark Hair for Electrochemical Applications

Biomass with abundant resources and low price is regarded as potential sources of functionalized carbon-based energy storage and conversion electrode materials. Rational construction and development of biomass-derived carbon equipped with proper morphology, structure, and composition prove the key to highly efficient utilization of advanced energy storage systems. Herein, we use palm tree bark hair as a biomass source and prepare edge/defect-rich quasi-mesoporous carbon (QMC) by a direct pyrolysis followed by NaOH etching strategy. Then, the edge-rich quasi-mesoporous nitrogen-doped carbon (QMNC) is successfully fabricated through the hydrothermal method by making use of edge/defect-rich QMC and urea as carbon precursor and nitrogen source, respectively. The microstructure and composition of the resultant carbon materials are all detected by a series of techniques. In the meantime, the influence of the etching process on the preparation and electrochemical performance of edge-rich QMNC is systematically explored. The relevant results manifest that the as-prepared edge/defect-rich QMC not only possesses edge-rich plane, much increased specific surface area (SSA), and special quasi-mesopores but also reverses good conductivity and gains sufficient defects for subsequent N doping. After introducing N atoms, the obtained edge-rich QMNC exhibits outstanding capacitive property and oxygen reduction reaction performance, which are mainly attributed to the co-effect of edge-rich plane, large SSA, suitable pore structures, and effective N doping (including high doping amount and optimized N configurations). Clearly, our work not only offers an excellent biomass-derived carbon-based electrode material but also opens a fresh avenue for the development of advanced biomass-derived carbon-based electrode materials