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Rechargeable aqueous ammonium-ion batteries (AAIBs) have attracted more and more attention in energy storage devices because of great safety and cost-effectiveness, as well as excellent rate capability. Recently, it is the main exploration focus for the further improvement of AAIBs to develop suitable electrode materials. Herein, titanic acid and TiO2 were simply synthesized by the facile co-precipitation approach. Titanic acid showed higher capacity of 104.5 mAh g−1 at the 0.1 A g−1 current density, and higher cyclability with the 91.2% capacity retention cycled 1000 cycles at 1 A g−1. Titanic acid is promising as aqueous ammonium-ion batteries with great stability and capacity. [ABSTRACT FROM AUTHOR]

• Copper sulfide (Cu x S) was first selected as electrode materials for AAIBs. • The flower-like CuS exhibited outstanding NH 4 + storage performance. • The NH 4 + energy storage mechanism in CuS host was revealed. • The electrolyte composition was adjusted to effectively improve the electrode stability. The aqueous ammonium-ion batteries (AAIBs) exhibit significant significance because of their high energy, cost-effectiveness, environmental friendliness, and high safety. Nonetheless, electrode materials with good cycle stability as well as great capacity have a crucial role in developing aqueous ammonium ion batteries. Herein, flower-like CuS microspheres were successfully utilized in AAIBs. The experimental results demonstrated that the as-synthetized copper sulfides revealed high conductivity and flower-like microspheres, and its initial discharge capacity was as high as 710 mAh g−1 at the 0.1 A g−1 current density. Moreover, the cycle stability of batteries were greatly improved by optimizing the electrolyte composition. These results represent a novel design strategy for the AAIBs. [Display omitted] [ABSTRACT FROM AUTHOR]

A Nb 2 O 5 compound with a structure similar to an air filter (AF-Nb 2 O 5) was synthesized using a hydrothermal method, and further calcined to form a product that was designated CAF-Nb 2 O 5. The morphology and microstructure of the AF-Nb 2 O 5 and CAF-Nb 2 O 5 were examined using X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The AF-Nb 2 O 5 and CAF-Nb 2 O 5 exhibited similar filter-like structures, which consisted of regular pores and ordered networks. The CAF-Nb 2 O 5 exhibited a high specific capacitance of 258 F g−1 at a current density of 0.5 A g−1, an excellent rate capacity of 172 F g−1 at the high current density of 5 A g−1 and an impressive capacitance retention of 90.5% after 5000 cycles at the current density of 2 A g−1. The CAF-Nb 2 O 5 exhibited excellent electrochemical properties by virtue of its abundance of ion channels and its filter-like structure. • A novel structured Nb 2 O 5 was achieved by hydrothermal method. • The novel structure is similar to air filter. • The air filter-like Nb 2 O 5 is an ideal electrode material for supercapacitors. • The air filter-like Nb 2 O 5 exhibits the excellent electrochemical performance. [ABSTRACT FROM AUTHOR]

This work focused on a fabrication of lotus root-like Li 3 V 2 (PO 4) 3 /C composites via a repeated immersion process using the dandelion as a bio-template. The Li 3 V 2 (PO 4) 3 /C composites were characterized using X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The Li 3 V 2 (PO 4) 3 /C composites exhibited various structures that were dependent on the various processing techniques. By increasing immersion of the product to three repetitions, a bundle of dandelion carbon fibers was found to be covered by Li 3 V 2 (PO 4) 3 and formed a perfect lotus root-like structure (D-3). The Li 3 V 2 (PO 4) 3 /C composite (D-V) prepared using the vacuum method displayed a dense scrub board-like structure. However, sample D-3 that was prepared using the novel method, exhibited a capacity of 126.8 mAh g−1 at the 1 C rate, a prominent capacity retention of 96.8% after 2000 cycles at the 15 C rate. The experimental results showed that this unique lotus root-like structure is beneficial for improving the capability and cycling stability. [ABSTRACT FROM AUTHOR]

Abstract CNTs microspheres were prepared by an ultrasonic spray method, selenium was subsequently loaded by molten diffusion strategy. The prepared Se/CNTs microspheres were characterized by X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM) including elemental mapping analysis, transmission electron microscopy (TEM), and thermogravimetric analysis (TGA). The CNTs are entangled into CNTs microspheres of uniform size and full of micropores, effectively increases the loading of selenium. Se/CNTs microspheres exhibit the initial capacity of 626 mAh g−1 at 0.2 C rate (1 C = 675 mA g−1), the capacity of 390 mAh g−1 at 5 C rate, and capacity retention of 80% after 500 cycles at 1 C rate. These excellent properties indicate that the Se/CNTs microspheres material is a potential material for Li-Se batteries. Highlights • Novel CNTs microspheres were synthesized by an ultrasonic spray method. • The CNTs were intertwined into porous microspheres. • Porous CNTs microspheres become the excellent host for Se particles. • Se/CNTs microspheres exhibit remarkable rate performance and cycle stability. [ABSTRACT FROM AUTHOR]

Abstract This work focused on the design and fabrication of porous, nitrogen-doped Li 3 V 2 (PO 4) 3 /C cathode materials using a repeated impregnation synthesis process employing oroxylum as a template. The resulting Li 3 V 2 (PO 4) 3 /C cathode materials were comprehensively analyzed using Fourier transform infrared spectroscopy, X-ray diffraction analysis, selected area electron diffraction, scanning electron microscopy and galvanostatic experiments. The Li 3 V 2 (PO 4) 3 /C cathode materials of varying structure were prepared by various processing techniques using select precursors. The resulting porous, nitrogen-doped Li 3 V 2 (PO 4) 3 /C cathode materials (IM-15) obtained using repeated impregnation exhibited a novel, overlapping hollow slab structure, which was covered by thin layers of porous, foamed Li 3 V 2 (PO 4) 3 on the surface of IM-15. It was found that the porous, foamed Li 3 V 2 (PO 4) 3 material was sandwiched between thin layers of adjacent Li 3 V 2 (PO 4) 3 /C layers. IM-15 product exhibited an outstanding rate capability of 87.4 mAh g−1 at the 10 C rate, and an excellent capacity retention of 96.9% after 1000 cycles at 5 C in the range of 3–4.3 V. These results were attributed to the porous, nitrogen-doped structure of the material, which provided a high diffusion coefficient and superior structural stability. The unique porous, nitrogen-doped structure was responsible for improving the rate capability and cycling stability of LIBs containing the subject experimental material. [ABSTRACT FROM AUTHOR]

LiFePO 4 /C ultra-thin nanoflakes have been synthesized via evaporative self-assembly induced by squaric acid and successfully applied for cathode materials in full cell. The morphologies and structures were characterized by X-ray diffractometer, scanning electron microscopy and transmission electron microscopy. Some LiFePO 4 /C nanoparticles about 40–80 nm in diameter are connected by LiFePO 4 /C ultra-thin nano-flakes which are constructed by squaric acids, other LiFePO 4 nanoparticles are embedded in the ultra-thin carbon nanoflakes. LiFePO 4 /C ultra-thin nano-flakes deliver a initial discharge capacity of 164 mAh g −1 at 0.2C rate and 92 mAh g −1 at 50 C rate. Its capacity retention is still 96% at 10 C rate after 1000 cycles. The unique LiFePO 4 /C ultra-thin nano-flakes can effectively increase the contact between electrode and electrolyte, improve the electronic and ionic conductivity and promote the transportations for lithium ions. [ABSTRACT FROM AUTHOR]

Porous carbons derived from tea seed shells were fabricated through hydrothermal activation and high-temperature activation. The microstructure was investigated via X-ray diffraction, Raman spectrometer, scanning and electron microscopy techniques. The activated carbons show high specific surface areas and developed porosity, and reveal excellent electrochemical performance, especially for the TSSCB samples. When the carbon material TSSCB was applied for lithium-ion batteries, it delivered superior specific charge capacity of 598 mAh g-1 at 0·1C, and showed an impressive rate capability of 440 mAh g-1 at 1C, and maintained high capacity retention of 82·9% even after 500 cycles. Moreover, when the carbon material TSSCB was utilized in supercapacitor, it also exhibited high specific capacitance of 305·7 F g-1 at the current density of 1 A g-1 and the capacitance retention ratio of 98·6% after 10,000 cycles, indicating remarkable cycling stability. Porous carbons derived from tea seed shells are a potential energy storage material. [ABSTRACT FROM AUTHOR]

Hierarchical porous LiFePO4/C composite has been successfully synthesised via evaporative self-assembly induced by vegetable proteins. The morphologies and structures are investigated by X-ray diffractometer, scanning electron microscope and transmission electron microscope. Hierarchical porous LiFePO4/C composite presents the connected hierarchical porous structure and nano-carbon network embedded in connected hierarchical pores. LiFePO4/C composite with 5 wt% vegetable proteins (LFP-5C) delivers a higher capacity of 166.8 mA h g−1than LiFePO4/C composite with 8 wt% vegetable protein (LFP-8C) (161.4 mA h g−1) at 0.1 C rate. However, at a high rate of 30 C, LFP-8C exhibits a little higher discharge capacity of 148.6 mA h g−1and capacity retention of 97.3% after 100 cycles than LFP-5C (145.6 mA h g−1, 96.8%). The hierarchical porous LiFePO4/C composite is a promising material for practical application in lithium-ion battery. [ABSTRACT FROM PUBLISHER]

LiFePO 4 /carbon nanowires with three-dimensional (3D) nano-network structure were successfully synthesized via evaporative self-assembly method induced by amylose. The morphologies and structures are investigated by X-ray diffractometer, scanning electron microscope and transmission electron microscope. The co-axis one-dimensional LiFePO 4 /C nanowires, which are 50 nm in diameter and between 400 nm and 1 μm in length, are tightly connected into 3D nano-network structure by the amorphous carbon from the short branched chains of amylase. They deliver high capacities of 167 and 138 mA h g −1 at 0.1 C and 50 C respectively. After 100 cycles at 50C rate, the capacity retention of the composite can still maintain 92.8% (128 mA h g −1 ).The unique 3D nano-network structure can effectively increase the contact between active materials and electrolyte, and improve the poor electronic and ionic conductivity. [ABSTRACT FROM AUTHOR]

The practical application of Si-based materials has been impeded by poor cycling stability. The cage-like silicon/carbon microspheres were fabricated via a series of procedures: the allometric nucleation, magnesiothermic reduction and selective etching. The microstructure, morphology and electrochemical performance for cage-like silicon/carbon microspheres were investigated by X-ray photoelectron spectra, scanning electron microscopy, transmission electron microscopy and galvanostatic charge-discharge tests. The cage-like carbon shell can effectively absorb the volume expansion and restrain the pulverization for silicon electrodes due to its excellent flexibility and toughness, and particular structure. The cage-like silicon/carbon microspheres reveal an outstanding charge capacity of 1926 mA h g−1 at 0.1 C, and still remain 1790 mA h g−1 after 200 cycles. They exhibit an excellent rate capacity of 916 mA h g−1 and capacity retention of 96% after 1000 cycles at 5 C. The design strategy of the cage-like carbon shell structure offers a novel path for improving the electrochemical performance of silicon-based materials. • The CSCMs can effectively prevent the volume effect and the powdering of Si. • The CSCMs can provide high porosity to facilitate the diffusion of Li+, thereby improving the electronic conductivity. • The remarkable rate performance of CSCMs is obtained because of the unique cage-like core-shell structure. [ABSTRACT FROM AUTHOR]

LiFePO 4 and LiFePO 4 /C microspheres are successfully synthesized via facile co-precipitation in an elevated temperature oil bath. Their morphologies and structures are investigated by X-ray diffractometer, scanning electron microscope and transmission electron microscope. LiFePO 4 /C microspheres are uniform between 2 and 4 μm in diameter and composed of nanoparticles from 30 to 80 nm in size. Nanoparticles are coated by a thin nano-carbon layer and imbedded into three-dimensional nano-carbon networks. LiFePO 4 /C microspheres exhibit a high tap density (1.82 g cm −3 ), deliver large reversible discharge capacity of 165 mA h g −1 at 0.1C rate, excellent rate capability of 106 mA h g −1 at 50C rate, and capacity retention over 98% after 20 cycles even applied 50C rate. Therefore, the material is a potential candidate for high-power lithium ion batteries. [ABSTRACT FROM AUTHOR]

Abstract: LiFePO4/C composite with network connections of nano-carbon wires was successfully prepared by using polyvinyl alcohol as carbon source. The composite was characterized by X-ray diffraction and transmission electron microscopic, and its electrochemical performance was investigated by galvanostatic charge and discharge tests. The experimental results show that LiFePO4 grains are tightly connected by the network of nano-carbon wires. Moreover LiFePO4/C composite exhibits high capacity of 168mAhg−1 applied 15mAg−1 current density (C/10), excellent cyclic ability and rate capability. When 1500mAg−1 current density (10C) was applied, the high discharge capacity of 129mAhg−1 has been obtained at room temperature. [ABSTRACT FROM AUTHOR]

It is worthy of attention that the honeycombed Li 3 V 2 (PO 4) 3 /C composites have been prepared and used as the cathode materials for lithium-ion batteries. The honeycombed Li 3 V 2 (PO 4) 3 /C composites were synthesized via vacuum-assisted immersion method using the dandelion fibers as the biomass-carbon templates. The composites were characterized using X-ray diffraction, transmission electron microscopy and scanning electron microscopy. The honeycombed Li 3 V 2 (PO 4) 3 /C composites exhibit a capacity of 123.40 mA h g−1 and a prominent capacity retention of 98.78% at the 0.2 C rate, while the rate capacity retention is as high as 88.84% at 15 C rates. It is demonstrated that the unique honeycombed structure is beneficial for improving structural stability and Li+ diffusion coefficient of the lithium ion batteries, and then enhance the high-rates and cycle performance. • The honeycombed Li 3 V 2 (PO 4) 3 /C composites are constructed by using biomass-carbon as template. • The honeycombed Li 3 V 2 (PO 4) 3 /C composites depend on the vacuum-assisted immersion process. • The honeycombed Li 3 V 2 (PO 4) 3 /C composites exhibit remarkable rate capability. [ABSTRACT FROM AUTHOR]