6 research outputs found

    Evolution of Useless Iron Rust into Uniform α‑Fe<sub>2</sub>O<sub>3</sub> Nanospheres: A Smart Way to Make Sustainable Anodes for Hybrid Ni–Fe Cell Devices

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    The large amount of iron rust yielded in steel industries is undoubtedly a useless and undesired product since its substantial formation and recycle/smelting would give rise to enormous financial costs and environmental pollution issues. To best reuse such rusty wastes, we herein propose a smart and applicable method to convert them into uniform α-Fe<sub>2</sub>O<sub>3</sub> nanospheres. Only after a simple and conventional hydrothermal treatment in HNO<sub>3</sub> solution, nearly all of the iron rust can evolve into sphere-like α-Fe<sub>2</sub>O<sub>3</sub> products with a typical size of ∼30 nm. When serving as actives for electrochemical energy storage, the <i>in situ</i> generated α-Fe<sub>2</sub>O<sub>3</sub> nanospheres exhibit prominent anodic performance, with a maximum specific capacity of ∼269 mAh/g at ∼0.3 A/g, good rate capabilities (∼67.3 mAh/g still retains even at a high rate up to 12.3 A/g), and negligible capacity degradation among 500 cycles. Furthermore, by paring with activated carbons/Ni cathodes, a unique full hybrid Ni–Fe cell is constructed. The assembled full devices can be operated reversibly at a voltage as high as ∼1.8 V in aqueous electrolytes, capable of delivering both high specific energy and power densities with maximum values of ∼131.25 Wh/kg and ∼14 kW/kg, respectively. Our study offers a scalable and effective route to transform rusty wastes into useful α-Fe<sub>2</sub>O<sub>3</sub> nanospheres, providing an economic way to make sustainable anodes for energy-storage applications and also a platform to develop advanced Fe-based nanomaterials for other wide potential applications

    FeF<sub>3</sub>@Thin Nickel Ammine Nitrate Matrix: Smart Configurations and Applications as Superior Cathodes for Li-Ion Batteries

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    Iron fluorides (FeF<sub><i>x</i></sub>) for Li-ion battery cathodes are still in the stage of intensive research due to their low delivery capacity and limited lifetime. One critical reason for cathode degradation is the severe aggregation of FeF<sub><i>x</i></sub> nanocrystals upon long-term cycling. To maximize the capacity and cyclability of these cathodes, we propose herein a novel and applicable method using a thin-layered nickel ammine nitrate (NAN) matrix as a feasible encapsulation material to disperse the FeF<sub>3</sub> nanoparticles. Such core–shell hybrids with smart configurations are constructed via a green, scalable, in situ encapsulation approach. The outer thin-film NAN matrix with prominent electrochemical stability can keep the FeF<sub>3</sub> nanoactives encapsulated throughout the cyclic testing, protecting them from adverse aggregation into bulk crystals and thus leading to drastic improvements of electrode behaviors (e.g., high electrode capacity up to ∼423 mA h g<sup>–1</sup>, greatly prolonged cyclic period, and promoted rate capabilities). This present work may set up a new and general platform to develop intriguing core–shell hybrid cathodes for Li-ion batteries, not only for FeF<sub><i>x</i></sub> but also for a wide spectrum of other cathode materials

    Smart Magnetic Interaction Promotes Efficient and Green Production of High-Quality Fe<sub>3</sub>O<sub>4</sub>@Carbon Nanoactives for Sustainable Aqueous Batteries

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    Efficient and green production of monodispersed Fe<sub>3</sub>O<sub>4</sub>@carbon (C) nanoactives for commercial aqueous battery usage still remains a great challenge due to issues related to tedious hybrid fabrication and purification procedures. Herein, we put forward an interesting applicable synthetic strategy via a general polymeric process and simple magnetic purification treatments, enabling low-cost and massive production of high-quality Fe<sub>3</sub>O<sub>4</sub>@C hybrids. In such core–shell configurations, all Fe<sub>3</sub>O<sub>4</sub> nanoparticles are tightly encapsulated in permeable <i>N</i>-doped C nanoreactors, showing notable nanostructured superiorities as feasible anodes for aqueous batteries. When tested, the Fe<sub>3</sub>O<sub>4</sub>@C nanoactives exhibit outstanding anodic performance comprising pretty high electrochemical activity/capacity, greatly prolonged cyclic lifespan in contrast to bare Fe<sub>3</sub>O<sub>4</sub> counterparts, and prominent rate capabilities. The as-assembled Ni/Fe full cells can even deliver a high energy/power density up to ∼135 Wh kg<sup>–1</sup>/11.5 kW kg<sup>–1</sup>, further demonstrating their good potential in practical applications. Our smart magnetic purification strategy may hold great promise in addressing critical issues of producing high-quality and affordable Fe<sub>3</sub>O<sub>4</sub>@C hybrids, not only for energy-storage fields but also in other broad ranges covering catalysts and biosensors

    Engineering 3D Interpenetrated ZIF‑8 Network in Poly(ethylene oxide) Composite Electrolyte for Fast Lithium-Ion Conduction and Effective Lithium-Dendrite Inhibition

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    A novel 3D ZIF-8 network-reinforced polyethylene oxide (PEO) composite polymer electrolyte (Z-C-PAN-PEO) is successfully built, in which the network with an interpenetrated structure is tactfully developed by in situ assembling ZIF-8 nanoparticles on electrospinning carboxylated polyacrylonitrile (C-PAN) nanofiber surfaces. ZIF-8 with high porosity and unsaturated open metal sites will act as the bridge between C-PAN nanofibers and the PEO matrix. It is proven that the selected ZIF-8 can play a significant role in facilitating Li+ conduction and transference by effectively interacting with the oxygen atoms of C–O–C to promote the segmental movement of PEO and immobilizing TFSI– anions to release more free Li+. The 3D interpenetrating structure of Z-C-PAN further enables the conduction channels more consecutive and long-ranged, endowing the Z-C-PAN-PEO electrolyte with an optimum ionic conductivity of 4.39 × 10–4 S cm–1 and a boosted Li+ transference number of 0.42 at 60 °C. Other improvements occurring in the reinforced electrolytes are the broaden electrochemical stability window of ∼4.9 V and sufficient mechanical strength. Consequently, the stable Li-plating/stripping for 1000 cycles at 0.1 mA cm–1 witnesses the splendid compatibility against Li dendrite. The cycling performance of LiFePO4/Z-C-PAN-PEO/Li cells with a reversible capacity of 116.2 mAh g–1 after 600 cycles at 0.2 C guarantees the long-term running potential in lithium metal batteries. This study puts forward new insights in designing and exploiting the active role of MOFs for high-performance solid polymer electrolytes

    Efficient Production of Coaxial Core–Shell MnO@Carbon Nanopipes for Sustainable Electrochemical Energy Storage Applications

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    Adverse structural changes and poor intrinsic electrical conductivity as well as the lack of an environmentally benign synthesis for MnO species are major factors to limit their further progress on electrochemical energy storage applications. To overcome the above constraints, the development of reliable and scalable techniques to confine MnO within a conductive matrix is highly desired. We herein propose an efficient and reliable way to fabricate coaxial core–shell hybrids of MnO@carbon nanopipes merely via simple ultrasonication and calcination treatments. The evolved MnO nanowires disconnected/confined in pipe-like carbon nanoreactors show great promise in sustainable supercapacitors (SCs) and Li-ion battery (LIB) applications. When used in SCs, such core–shell MnO@carbon configurations exhibit outstanding positive and negative capacitive behaviors in distinct aqueous electrolyte systems. This hybrid can also function as a prominent LIB electrode, demonstrating a high reversible capacity, excellent rate capability, long lifespan, and stable battery operation. The present work may shed light on effective and scalable production of Mn-based hybrids for practical applications, not merely for energy storage but also in other broad fields such as catalysts and biosensors

    One-Dimensional Integrated MnS@Carbon Nanoreactors Hybrid: An Alternative Anode for Full-Cell Li-Ion and Na-Ion Batteries

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    Manganese sulfide (MnS) has triggered great interest as an anode material for rechargeable Li-ion/Na-ion batteries (LIBs/SIBs) because of its low cost, high electrochemical activity, and theoretical capacity. Nevertheless, the practical application is greatly hindered by its rapid capacity decay lead by inevitable active dissolutions and volume expansions in charge/discharge cycles. To resolve the above issues in LIBs/SIBs, we herein put forward the smart construction of MnS nanowires embedded in carbon nanoreactors (MnS@C NWs) via a facile solution method followed by a scalable in situ sulfuration treatment. This engineering protocol toward electrode architectures/configurations endows integrated MnS@C NWs anodes with large specific capacity (with a maximum value of 847 mA h g<sup>–1</sup> in LIBs and 720 mA h g<sup>–1</sup> in SIBs), good operation stability, excellent rate capabilities, and prolonged cyclic life span. To prove their potential real applications, we have established the full cells (for LIBs, MnS@C//LiFePO<sub>4</sub>; for SIBs, MnS@C//Na<sub>3</sub>V<sub>2</sub>(PO<sub>4</sub>)<sub>3</sub>), both of which are capable of showing remarkable specific capacities, outstanding rate performance, and superb cyclic endurance. This work offers a scalable, simple, and efficient evolution method to produce the integrated hybrid of MnS@C NWs, providing useful inspiration/guidelines for anodic applications of metal sulfides in next-generation power sources
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