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Abstract Searching for advanced anode materials with exceptional electrochemical performance is essential for next-generation rechargeable batteries. The selection and structural design of anode materials are pivotal in the development of high-performance batteries. Herein, we demonstrate the preparation of uniform NiCo 2 O 4 nanotubes via a simple and cost-effective electrospinning technique followed by calcination in the air. Impressively, the advantages and importance of NiCo 2 O 4 nanotubes as an anode in lithium-ion batteries (LIBs) is demonstrated, which surpass their respective monometallic oxides in terms of electrochemical performance. Encouragingly, the as-obtained NiCo 2 O 4 nanotubes as an anode for sodium-ion batteries (SIBs) exhibit appealing electrochemical performance, such as high initial discharge capacity (879 mAh g−1 at 100 mA g−1), good rate capability, and excellent cycling stability. Moreover, a reversible capacity of 420 mAh g−1 at a current density of 100 mA g−1 can be maintained even after 100 cycles, corresponding to around 72% of the second cycle discharge capacity (584 mAh g−1). It is worth noting that this facile technique may provide a feasible way for the preparation of other functional materials with tube-like architectures for application in energy-storage device. Graphical abstract An advanced NiCo 2 O 4 nanotubes anode has been successfully prepared through a simple and cost-effective electrospinning technique followed by calcination in air. The as-obtained NiCo 2 O 4 nanotubes exhibits appealing electrochemical performance, such as high initial discharge capacity, good rate capability, and excellent cycling stability. Image 1 Highlights • NiCo 2 O 4 nanotubes are prepared through an electrospinning technique. • The NiCo 2 O 4 nanotubes surpass their respective monometallic oxides in terms of electrochemical performance in LIBs. • The NiCo 2 O 4 nanotubes as anode for SIBs present excellent electrochemical properties. • The electrospinning technique can be extended to prepare other functional materials in energy-storage devices. [ABSTRACT FROM AUTHOR]

A facile two-step method is developed to synthesize three dimensional (3D) hierarchical CaCo 2 O 4 architectures as high-performance electrode materials for lithium ion batteries (LIBs) and oxygen evolution reaction (OER). Our strategy involves a simple poly(vinylpyrolidone) (PVP)-assisted hydrothermal route and subsequent thermal treatment to produce flowerlike CaCo 2 O 4 nanostructures with a size of ∼500 nm, which is constructed by some neighboring vertical nanoplates. Whereas, the absence of PVP results in the formation of CaCo 2 O 4 microspheres, further indicating the vital role of PVP in favor of the oriented crystal growth of Co-based oxides. Benefited from the unique structural features, the resultant CaCo 2 O 4 nanoflower presents excellent cycling stability (∼560 mAh g−1 after 100 cycles at 50 mA g−1) and remarkable rate capability. Apart from superior lithium storage properties, more strikingly, CaCo 2 O 4 nanoflower demonstrates a promising candidate as a noble metal-free electrocatalyst for oxygen evolution reaction, which will spur us to find more novel functional nanomaterials for wide applications. • 3D hierarchical CaCo 2 O 4 architectures have been synthesized. • CaCo 2 O 4 nanoflower presents high lithium-storage performance. • CaCo 2 O 4 nanoflower presents high oxygen evolution reaction performance. [ABSTRACT FROM AUTHOR]

• Silicon is obtained from photovoltaic industrial waste through simple purification. • N-doped carbon ensures fast charge transfer and structural stabilization. • Si/NC electrode has a high specific capacity both in half-cell and full-cell. Silicon (Si) is considered to be one of the most promising anode materials for the next generation of lithium-ion batteries (LIBs). However, the practical application of Si anode is still high cost and hindered by huge volume change. It is significant to produce high-performance Si anode of LIBs inexpensively. Herein, we report the Si/N-doped carbon (Si/NC) composite anode materials constructed by recycling Si waste from the photovoltaic industry as raw materials after simple purification and polydopamine (PDA)-derived carbon coating. The Si micro/nano-plates coated with the NC can facilitate electron transfer and inhibit the volume expansion of Si to stabilize the structure of composites. The resulting Si/NC electrode exhibits a high discharge capacity of 1139 mAh g−1 at 1 A g−1 over 200 cycles. Moreover, the full-cell (LiFePO 4 //Si/NC) presents excellent cycling performance (108 mAh g−1 at 0.5 A g−1 over 200 cycles). This work not only offers a reasonable solution for the acquirement of Si anode from the photovoltaic industry but also provides a new strategy for the preparation of anodes for the next generation of LIBs, which may bring great economic benefits. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) layered materials were widely investigated due to their unique sodium storage properties and rapid ion transport rates. Herein, we synthesized a 2D layered transition metal phosphorus sulfide MnPS 3 by one step high-temperature solid-phase synthesis. After combining with graphene by high-energy ball milling followed by high-temperature argon calcination, the novel 2D/2D heterojunction of extra-thin MnPS 3 /rGO was successfully prepared. The resultant MnPS 3 /rGO hybrid can strengthen the conductivity of the material and ameliorate the volume change during the insertion/extraction process of the sodium-ion storage, compared to the pristine MnPS 3. As a result, the 2D/2D heterojunction of ultra-thin MnPS 3 /rGO composite exhibits high cycling performance (290 mAh g−1 after 150 cycles at 0.2 A g−1), capacity retention rates up to 92%. The superior performance is ascribed to the combination of extra-thin MnPS 3 nanosheets with graphene, which effectively enhances the interface contact area and the electronic transmission rate, greatly improving the adaptability of volume change and interfacial charge transfer abilities. This work provides a novel and promising MnPS 3 /rGO anode for sodium-ion batteries. Image 1 • Two-dimensional (2D) layered structure possesses rapid ion transport rates. • A novel 2D/2D heterojunction of MnPS 3 /rGO composites was synthesized by high-energy ball milling. • The introduction of various carbon species into 2D materials can effectively ameliorate the structure stability of materials. [ABSTRACT FROM AUTHOR]