The combination of two or more seemingly distinct properties into a unique composite is an exciting direction for the fabrication of novel multifunctional materials. A vacuum-filtration method was used to fabricate strong and multifunctional heparin/layered double hydroxide (HEP/LDH) films mimicking nacre. The experimental results confirm that the prepared films show a layered nano/microscale-hierarchical structure, in which the LDHs are aligned, with a very high loading amount of LDHs closely comparable to that in the natural nacre, up to 87.5 wt %. Both the modulus (Er ≈ 23.4 GPa) and hardness (H ≈ 0.27 GPa) of the HEP/LDH films are remarkably high. Furthermore, the hybrid films show a combination of outstanding properties of UV-blocking and fire-resistance properties. Therefore, this work provides a way of fabricating multifunctional organic–inorganic hybrid films, which have potential applications in the areas of optical applications, transportation, and construction.

•Mesoporous carbon (MC) is prepared by carbonization of zeolitic imidazolate frameworks-8.•MC is used as additive in modifying commercial LiFePO4 (LFP) by simple physical mix.•LFP@MC cathode exhibits high rate performance and high capacity retention ratio.In order to improve high rate and cycle performances of commercial LiFePO4 (LFP), mesoporous carbon (MC) is synthesized by carbonization of zeolitic imidazolate frameworks-8 (ZIF-8). As an additive, MC can improve both electronic conductivity and lithium ion diffusion coefficient of LFP due to its high conductivity and mesoporous structure. LFP mixing with MC delivers a high rate performance of 154.6 mAh g−1 at a current rate of 0.5 C and a capacity retention ratio of approximately 99.9% after 60 cycles at 10.0 C. Moreover, the discharge energy density is also improved due to the enhancement of discharge voltage platform.

•Atomic-scale AlPO4 film is developed as a coating material for LNMO cathode via ALD.•ALD AlPO4 coated LNMO exhibits significantly stabilized cycle performance.•AlPO4 film suppresses dissolution of Mn and maintains the integral structure of LNMO.•AlPO4 coating is transferred to a stable artificial SEI layer with Li-ion interactions.Spinel LiNi0.5Mn1.5O4 (LNMO) is a promising high voltage cathode material for lithium ion batteries (LIBs). However, dissolution of Mn and unwanted side reactions between LNMO and the electrolyte raises several safety issues while also resulting in deteriorated electrochemical performance of LIBs at high working voltages. Here, we report the use of ultrathin atomic layer deposited (ALD) AlPO4 thin film as a coating material for LNMO electrodes to circumvent the stated issues. The as-prepared AlPO4 coated LNMO demonstrates excellent capacity retention with prolonged cycle life compared to the bare one. Synchrotron based X-ray spectroscopy was employed to understand how ultrathin coating layer improve the cycle life, and then develop a detailed mechanism for the effect of coating layer. Our studies revealed that using atomic scale coating layer with improved thermal stability effectively impede the side-reactions occurrence at high voltage, resulting in significantly improved safety and electrochemical performances.Download high-res image (189KB)Download full-size image

High-voltage lithium-ion batteries (HVLIBs) are considered as promising devices of energy storage for electric vehicle, hybrid electric vehicle, and other high-power equipment. HVLIBs require their own platform voltages to be higher than 4.5 V on charge. Lithium nickel manganese spinel LiNi0.5Mn1.5O4 (LNMO) cathode is the most promising candidate among the 5 V cathode materials for HVLIBs due to its flat plateau at 4.7 V. However, the degradation of cyclic performance is very serious when LNMO cathode operates over 4.2 V. In this review, we summarize some methods for enhancing the cycling stability of LNMO cathodes in lithium-ion batteries, including doping, cathode surface coating, electrolyte modifying, and other methods. We also discuss the advantages and disadvantages of different methods.

•We review the recent progresses of the lithium dendrite suppression in LSBs.•Modifications of anode and electrolyte are used in improving safety of LSB anodes.•Electrolyte additive suppresses dendrite by modifying electrolyte/anode interface.•Seeking the novel separator with 3D structure will be a new route.Lithium sulfur batteries (LSBs) are attractive owing to the high theoretical capacities of sulfur cathode active material (1672 mAh g−1) and lithium anode active material (3862 mAh g−1), which leads to a specific energy of approximately 2600 Wh kg−1. However, for any rechargeable batteries employing lithium metal as the anode, a major failure mechanism is uncontrolled dendrite formation, which presents serious safety issues, low Coulombic efficiency and poor cycle performance. Recently, researchers make great effort to overcome these problems. Here we summarize some methods for suppressing lithium dendrite growth based on the failure mechanism of LSBs, mainly including novel separator, anode modification and electrolyte modification. We also discuss the advantages and disadvantages of different methods and point out the challenges that still needed to be addressed for building better LSBs.

Double-shell LiNi0.5Mn1.5O4 (LNMO-DS) hollow microspheres have been synthesized via a facile molten salt and annealing method. This method is a heating and cooling process with programmed control, which can promote the formation of a double-shell hollow microspherical structure and suppress rock-salt impurity phase. The LNMO-DS material with an average size of about 1 μm has outer and inner shells with thicknesses of all about 100 nm, which is confirmed by transmission electron microscopy (TEM). The double shell structures allow easy penetration of the electrolyte into the whole microspheres and buffer the large volume change of the electrode materials during Li ion intercalation/deintercalation processes. When applied as cathode materials for Li ion batteries, LNMO-DS exhibit high reversible capacity, excellent cycling and rate performances. The capacities remain at about 98.3% after 100 cycles (116.7 mA h g−1 at 0.5C). Furthermore, the favorable electrochemical performances of LNMO-DS are suitable for them to be used as the positive electrode in full cells.

Composite of Co3O4 nanorods with reduced graphene oxide (RG-Co3O4) for rechargeable zinc-air battery was prepared by a facile method. The Co3O4 nanorods with a length of 1–2 μm were homogeneously distributed on the surface of plicated graphene nanosheets. The samples were characterized by X-ray diffraction, scanning electron microscopy, and Raman spectroscopy. The RG-Co3O4 composite showed better electrode potential and higher electrical conductivity compared with pure Co3O4. The zinc-air battery can be reversibly charged and discharged for hundred cycles with a good cycle performance. The improved battery performance of RG-Co3O4 can be attributed to the synergistic coupling effect between the graphene sheets and Co3O4.

We describe in this paper the synthesis and the characterization of Li4Ti5O12-reduced graphene oxide (LTO-RGO) composite and demonstrate their use as hybrid supercapacitor, which is consist of an LTO negative electrode and activate carbon (AC) positive electrode. The LTO-RGO composites were synthesized using a simple, one-step process, in which lithium sources and titanium sources were dissolved in a graphene oxide (GO) suspension and then thermal treated in N2. The lithium-ion battery with LTO-RGO composite anode electrode revealed higher discharge capacity (167 mAh g−1 at 0.2 C) and better capacity retention (67%) than the one with pure LTO. Meanwhile, compared with the AC//LTO supercapacitor, the AC//LTO-RGO hybrid supercapacitor exhibits higher energy density and power density. Results show that the LTO-RGO composite is a very promising anode material for hybrid supercapacitor.

The porous WO3/reduced graphene oxide (rGO) composite films are prepared on indium–tin oxide (ITO) glass by sol-gel method. The mixture sol combines peroxotungstic acid solution with rGO dispersion reduced by ethylene glycol (EG). The excessive EG and other organic additives are subsequently removed by annealing, which leads to the formation of porous structure. Compared with pure WO3 film, WO3/rGO composite film shows improved electrochromic performance because of enhanced double insertion/extraction of ions and electrons. It realizes a large optical modulation (64.2 % at 633 nm), fast switching speed (9.5 s for coloration and 4.5 s for bleaching), good cycling stability as well as reversibility.

Gold nanoparticles–layered double hydroxide–poly(vinyl alcohol) (Au NPs–LDH–PVA) hybrid films have been successfully prepared for the first time by bottom-up assembly of pretreated Au NPs–LDH nanosheets and subsequent spin-coating of PVA. The cross sections of the as-prepared hybrid films resemble the brick-and-mortar structure of nacre. The tensile strength of the Au NPs–LDH–PVA hybrid film reaches a high value of 122 MPa, which is higher than that of a pure PVA film and surpasses the strength of natural nacre. Furthermore, we demonstrate that Au NPs–LDH–PVA hybrid films possess surface-enhanced Raman scattering and catalytic properties. Therefore, our report on the fabrication of multifunctional Au NPs–LDH–PVA hybrid films not only shows a feasible route to functionalizing artificial nacre-inspired materials but also potentially broadens applications of these nacre-like materials.

Tungsten oxide (WO3) films were prepared on indium–tin oxide (ITO) glass by sol–gel method. The influence of annealing temperature on the structural, morphological, optical, electrochemical, and electrochromic properties has been investigated. The film annealed at 250 °C with an amorphous structure exhibits a noticeable electrochromic performance, such as the highest optical modulation of 58.5 % at 550 nm, high electrochemical stability, and excellent reversibility (Qb/Qc = 96.3 %). An electrochromic (EC) device based on WO3/NiO complementary structure shows improved performance. It exhibits high optical transmittance modulation of 62 % at 550 nm, excellent cycling stability, and relatively fast electrochromic response time (10 s for coloration and 19 s for bleaching).

Although studies have been done on nitrogen doped carbon materials as lithium–oxygen (Li–O2) battery cathodes, few of them focus on the binder-free electrode structure, although they have been proved to bring improved performance. To fill this gap this work not only studies the nitrogen doped binder-free carbon cathode but also determines the performance of these cathodes with different levels of nitrogen doping. To make binder-free electrodes, these CNTs and N-CNTs were synthesized on nickel foam by a floating catalyst chemical vapor deposition method. The study found that the electrochemical performance of binder-free N-CNT cathodes in Li–O2 batteries improves as the level of nitrogen doping increases. To further study the reason why the electrodes with higher nitrogen amounts deliver better electrochemical properties, the morphology of discharge products on the different nanotubes are detected by scanning electron microscopy (SEM). The scan shows that the distribution of discharge products on the surface of CNTs become more and more uniform as the level of nitrogen doping increases and the discharge capacity and cycle performance are subsequently improved. Therefore, these binder-free N-CNT electrodes could be further explored as high capacity cathode materials for Li–O2 battery applications.

A novel Co3O4/flocculent graphene (FG) hybrid on commercial Ni foam (NF) has been prepared. The unique flocculent graphene structure is prepared by combining a rapid filtering approach through Ni foam and a template method, in which the thermally expanded graphite is used as precursor and polystyrene (PS) microspheres are used as templates. The PS spheres play an important role in preventing the re-stacking of graphene nanosheets and the formation of flocculent graphene on NF. The PS spheres were first introduced as a guest material and were subsequently removed by calcination. The resulting free-standing FG/NF provides a three-dimensional and high conductivity scaffold for the hydrothermal growth of Co3O4 nanoclusters. The obtained Co3O4/FG/NF hybrid could be directly used as a binder-free supercapacitor electrode. Moreover, the Co3O4 nanoclusters on FG/NF scaffold exhibit improved specific capacitance of 1615 F g−1 compared to that of the bare NF. The 3D active material layer of Co3O4/FG/NF hybrid, high conductivity of 3D FG/NF scaffold and functional features of the Co3O4 nanocluster morphology synergistically result in an improved electrochemical performance.

A morphology-controlled molten salt route was developed to synthesize porous spherical LaMnO3 and cubic LaMnO3 nanoparticles using the as-prepared porous Mn2O3 spheres as template. The porous LaMnO3 spheres with an average pore size of about 34.7 nm and the cubic LaMnO3 nanoparticles with a good dispersion were confirmed by scanning electron microscope, transmission electron microscope, and N2 adsorption–desorption measurements. The mechanism of morphological transformation from the porous spherical structure to the cubic particle in the molten salt was proposed. The porous spherical LaMnO3 and cubic LaMnO3 catalysts exhibited high catalytic performance for the combustion of toluene, and the latter performed better than the former. Under the conditions of toluene/oxygen molar ratio = 1/400 and space velocity = 20 000 h–1, the temperature required for 10, 50, and 90% toluene conversion was 110, 170, and 220 °C over the cubic LaMnO3 catalyst, respectively. Based on the results of X-ray photoelectron spectroscopic and hydrogen temperature-programmed reduction characterization, we deduce that the higher surface Mn4+/Mn3+ molar ratio and better low-temperature reducibility enhanced the catalytic performance of cubic LaMnO3. Taking the facile morphology-controlled synthesis and excellent catalytic performance into consideration, we believe that the well-defined morphological LaMnO3 samples are good candidate catalytic materials for the oxidative removal of toluene.Keywords: lanthanum manganate catalyst; molten salt synthesis; morphological control; toluene combustion

A new type of three-dimensional (3D) NiO/ultrathin derived graphene (UDG) hybrid on commercial Ni foam (NF) for a binder-free pseudocapacitor electrode is presented. NiO nanoflakes are in situ grown by a chemical bath deposition (CBD) technique on the free-standing 3D UDG/NF scaffold, which is first prepared by a simple nanocasting process consisting of hydrothermal reaction and subsequent thermal transformation. The 3D UDG/NF scaffold with interconnected network affords a high conductivity due to the high graphitization degree and efficiently facilitates the electron transport to NiO. Moreover, the 3D NiO/UDG/NF hybrid allows for a thinner 3D active material layer under the same loading density, which could shorten the diffusion paths of ions. The NiO/UDG/NF hybrid is directly used as a binder-free supercapacitor electrode, which exhibited significantly improved supercapacitor performance compared to the bare CBD prepared NiO/NF electrode.Keywords: 3D derived graphene; binder free; nanoflake; NiO; scaffold; supercapacitor;

Carbon nanotubes (CNTs) and nitrogen-doped carbon nanotubes (N-CNTs) were synthesized using a floating catalyst chemical vapor deposition method and characterized by scanning electron microscopy (SEM), transmission electron microscopy, Raman and X-ray photoelectron spectroscopy. The study found that the as-prepared CNTs and N-CNTs showed different discharge capacity as cathode materials in Li-air battery. To further study the reason why N-doping improves the electrochemical performance exceptionally, the discharge products on the two kinds of nanotubes were detected by SEM, XRD and Raman. SEM study showed, for the first time, that more uniform distribution of discharge products on the surface of CNTs arising from N-doping affected the boost of discharge capacity, a result which was discussed in detail. In comparison to non-doped CNTs, nitrogen doping was considered to be a promising way to improve the performance of carbon based cathode material for Li-air batteries.

Olivine lithium iron phosphate (LiFePO4) is considered as a promising cathode material for high power-density lithium ion battery due to its high capacity, long cycle life, environmental friendly, low cost, and safety consideration. The theoretical capacity of LiFePO4 based on one electron reaction is 170 mAh g−1 at the stable voltage plateau of 3.5 V vs. Li/Li+. However, the instinct drawbacks of olivine structure induce a poor rate performance, resulting from the low lithium ion diffusion rate and low electronic conductivity. In this review, we summarize the methods for enhancing the rate performance of LiFePO4 cathode materials, including carbon coating, elements doping, preparation of nanosized materials, porous materials and composites, etc. Meanwhile, the advantages and disadvantages of above methods are also discussed.

A novel non-hydrazine precursor solution followed by dip-coating has been developed to produce Cu2ZnSnS4 (CZTS) and Cu2ZnSn(S,Se)4 (CZTSSe) thin films. The precursor solution is based on an ethanol solution of metal–thioacetamide (TAA) complex with monoethanolamine (MEA) as the additive agent. By forming coordination complexes with TAA, metal cations are found to have good solubility in ethanol–MEA solvents, producing molecular-level blending in metal precursor solutions. All the materials are low-cost and environmentally friendly. The annealing treatments are conducted under vacuum and Se vapor to form CZTS and CZTSSe absorber films. A solar cell fabricated with the CZTSSe thin film exhibits power conversion efficiency of 5.36%, which is much higher than that (2.86%) of the cell using the CZTS thin film as absorber.

A facile topochemical route has been developed to synthesize porous LiMn2O4 spheres by using molten LiOH and porous Mn2O3 spheres as a template. The presence of pores with the average size of about 45 nm throughout the whole LiMn2O4 microspheres was confirmed by transmission electron microscope (TEM) and N2 adsorption–desorption measurements. When applied as cathode materials for rechargeable lithium-ion batteries, the porous sphere LiMn2O4 revealed stable high-rate capability. The discharge capacity is 83 mAh g−1 at 20 C rate, and it shows a good capacity retention after cycling at constantly changing discharge rate. Taking the excellent electrochemical performance and facile synthesis into consideration, the presented porous LiMn2O4 spheres could be a competitive candidate cathode material for high-performance lithium-ion batteries.Highlights► Porous LiMn2O4 spheres have been synthesized by a facile topochemical route. ► Molten LiOH reacted with porous Mn2O3 spheres, which was used as a template. ► The porous sphere LiMn2O4 revealed stable high-rate capability.

MnO2 nanorods/graphene composite materials have been fabricated using a facile hydrothermal method for supercapacitor applications. The prepared composite materials are characterized by means of X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and transmission electron microscope (TEM). Electrochemical performances are evaluated using cyclic voltammetry (CV), galvanostatic charge–discharge and electrochemical impedance spectrometry (EIS). It indicates that ratio of MnO2 nanorods to graphene in composite materials has significant influence on the electrochemical performance of composite electrodes. We have achieved the maximum specific capacitance of 218 F g−1 at the scan rate of 5 mV s−1 in 1 M Na2SO4 aqueous solution. Additionally, MnO2 nanorods/graphene composite materials exhibit highest energy density of 16 Wh kg−1 at power density of 95 W kg−1 and excellent capacitance retention with no more than 6% capacitance loss after 1000 cycles at the most favorable composites ratio.

•We prepared CZTSe films by selenization of co-electrodeposited Cu–Zn–Sn precursors.•Rapid thermal annealing (RTA) and conventional furnace annealing were performed.•RTA is conducive to the formation of pure phase CZTSe films with large grains.•A solar cell with efficiency of 4.5% using RTA–CZTSe absorber was achieved.Cu2ZnSnSe4 (CZTSe) thin films were prepared by selenization of co-electrodeposited Cu–Zn–Sn precursors, which were electrodeposited on Mo-coated glass substrates in one-step process. Two annealing processes, rapid thermal annealing (RTA) and conventional furnace annealing (CFA), were carried out for selenizing the precursors at 500 °C. The structure and morphology of the CZTSe thin films were characterized using X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDS). It is found that the RTA process benefits the formation of single phase CZTSe absorbers with large grains and the energy band gap of CZTSe film is 0.98 eV. Photovoltaic cells with the structure of glass/Mo/CZTSe/CdS/i-ZnO/ZnO:Al were fabricated using the RTA–CZTSe films as absorbers. The highest efficiency of 4.5% so far for a co-electrodeposited CZTSe solar cell was achieved.

We, the named authors, hereby wholly retract this CrystEngComm article due to data fabrication in Fig. 4 and 6. One of the spectra in Fig. 4, corresponding to nanocrystals of varying Sn/Ge content, has been copied and shifted within the figure: the purple spectrum (x = 1) is the copy of the black spectrum (x = 0). One of the plots in Fig. 6b, corresponding to nanocrystals of varying Sn/Ge content, has been copied and shifted: the blue curve (x = 0.3) is the copy of the green curve (x = 0.7). An investigation by Dr Yongping Lei (Professor and Chairman of College Council of the College of Materials Science and Engineering, Beijing University of Technology, China) determined that Kai Zong was responsible for these instances of data fabrication. Hao Wang, as his tutor and also corresponding author, is responsible for the duty of supervision and management. Other co-authors accept joint responsibility for the preparation of article. Please allow us to sincerely apologise to all readers and the Editorial Office.Signed: Kai Zhong, Si Heng Lu, Hao Wang, Yu Xiu Sun, Hui Juan Zheng, Jing Bing Liu, Hui Yan, 25 November 2013. This retraction is endorsed by Jamie Humphrey, Editor, CrystEngComm. Retraction published 13 December 2013.

As cathode materials, LiFePO4 particles have been investigated after a supercritical carbon dioxide (scCO2) treatment. We first produced LiFePO4 through a hydrothermal method. Then, scCO2 was introduced to change the morphology of the particles. Three effects have been found after the scCO2 treatment; the breakup of the aggregated LiFePO4 platelets into separate plates, the purification of LiFePO4, and the formation of porous LiFePO4. Electrochemical measurements showed that the performance of LiFePO4 greatly improved after the scCO2 treatment. Finally, a theoretical model was used to explain the mechanism of the morphology change.

In this study, Cu2ZnSnS4 (CZTS) thin films were successfully synthesized by the dip coating process using ethylene glycol as a solvent. The films were characterized by X-ray diffraction (XRD), Raman spectra, scanning electron microscope (SEM) and UV–vis spectra. The effect of the replacement of S by Se on the CZTS thin films was also discussed.Highlights► CZTS thin films were successfully synthesized in ethylene glycol-based solution, containing earth abundant CuCl2, ZnCl2, and SnCl2 salts, through the dip coating process. ► Ethylene glycol was used as a solvent, which is more environmental friendly, safe and less toxic in comparison with hydrazine. ► Thioacetamide (TAA) was adopted as a sulfur source, instead of thiourea, which should minimize the organic impurities of the material so that more volatile decomposition products are formed. ► The effect of the replacement of Se to S on the CZTS thin films was discussed.

Renewable nacre-like heparin (HEP)/layered double hydroxide (LDH) ultrathin films were first fabricated via a bottom-up layer by layer (LBL) deposition technique, which simultaneously showed largely enhanced mechanical properties and good blood compatibility. The results of UV-vis, FTIR, XRD and SEM analysis indicate that the HEP/LDH ultrathin films stacked densely together to form a well-defined brick-and-mortar structure. A strong electrostatic and hydrogen bond network at the organic–inorganic interface allowed the modulus of the film reach ca. 23 GPa, which was remarkably enhanced compared to previously reported polymer–LDH hybrid films. Due to the interlamellar heparin, the (HEP/LDH)n film may prove to be beneficial for new medical applications or as a replacement for conventional petroleum based plastics.

Indium sulfide (In2S3) thin films were prepared by chemical bath deposition using the mixed aqueous solutions of indium chloride, thioacetamide and citric acid, in which citric acid was used as the complexing agent. The films were investigated by x-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), the surface roughness automatic tester and UV–visible transmission spectra, respectively. The XRD results indicate that the as-deposited films at pH 1 and 2 are composed of β-In2S3 phase, which crystallize in cubic structure. The SEM images show that the surface morphologies of In2S3 films change from nanospheres to network-like morphologies with increase in growth time. Film thicknesses linearly increase with time and reach to balance stability finally. The ion-by-ion growth mechanism is proposed.

The shape of cathode electrode affects severely the potential curves of charge/discharge process of lithium ion cells. In this paper, we take LiFePO4 for an example. The square model is presented to predict the concentration of lithium on the cathode electrode under some simplified conditions. With the square model as a tool, effects of shape and position are determined and analyzed. Meanwhile, the lithium transportation, Gibbs free energy, and battery potential are proved to be different from that of sphere models. It shows that asymmetry of electrode materials makes a great impact on the performance of charge or discharge process.

The oriented growth of the hydroxyapatite (HAp) nanorod array on the glass substrate with a ZnO seed layer was investigated. The samples were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and transmission electron microscopy. The HAp nanorods have a length of about 2 μm and a diameter of about 200 nm. The growth mechanism of the (0001)-oriented HAp nanorod array was attributed to the “mold effect” of the (0001)-oriented ZnO seed layer. The dissolution characteristics of the as-prepared HAp nanorod array have also been investigated.

The three kinds of well-known bismuth molybdates α-Bi2Mo3O12, β-Bi2Mo2O9, and γ-Bi2MoO6 have been prepared employing mild hydrothermal methods. By tuning the Bi/Mo ratio and pH values, controlling formation of bismuth molybdates can be achieved. Low pH and high concentration of molybdenum lead to the formation of α-Bi2Mo3O12. High pH and high concentration of bismuth lead to the formation of γ-Bi2MoO6. The pure form of the β-phase can be prepared by calcining the hydrothermal product at 560 °C. Photophysical and photocatalytic studies show that Aurivillius structure γ-Bi2MoO6 shows an intense absorption band in the visible light region and better photocatalytic activity than α-Bi2Mo3O12 and β-Bi2Mo2O9 under visible light irradiation. The factors that result in different photocatalytic activities for three kinds of photocatalysts are discussed.

Pure Fe3O4 nanocrystals with different sizes were synthesized via hydrothermal processing of an easily obtained, air-stable metallorganic molecular precursor (ferric acetylacetonate: Fe-(ACAC)3) in 20 vol.% hydrazine hydrate aqueous solution at 80–160 °C for 0.5–12 h. The phase, purity and size of the resultant products were characterized by powder X-ray diffraction (XRD), Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR) and transmission electronic microscope (TEM), and the possible formation mechanism of Fe3O4 was tentatively proposed. The magnetic properties of the products have also been studied.

A simple hydrothermal method has been employed to prepare a series of lanthanide stannate pyrochlores Ln2Sn2O7 (Ln=Y, La, Pr–Yb) at a relatively low temperature of less than 200 °C successfully. On the basis of structural characterizations by X-ray powder diffraction (XRD), Fourier transform infrared (FT-IR) absorption spectroscopy and Raman spectroscopy, it was found that the positions of bands in vibrational spectra are sensitive to the ionic radius of Ln3+, and the linear relationship can be seen between the frequency of Sn–O stretching mode and the lanthanide ionic radius in IR spectrum, as well as the frequency of O–Sn–O bending mode and the lanthanide ionic radius in Raman spectrum.

Bismuth molybdate (Bi2MoO6) nanoplates have been successfully synthesized by a simple hydrothermal process. The nanoplates were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy, and IR spectroscopy. The effects of hydrothermal temperature and reaction time on the structures and morphologies of the nanoplates were investigated. On the basis of TEM observation of time series samples, a possible formation mechanism of the nanoplates was proposed. Optical absorption experiments revealed that Bi2MoO6 nanoplates had absorption in visible-light region, but a blue shift appeared compared with the corresponding bulk materials. Photocatalytic experiments showed that the nanoplates exhibited good photocatalytic activities for degradation of N,N,N′,N′-tetraethylated rhodamine (RhB) under visible-light irradiation (λ > 420 nm).

A mixture of cubic boron nitride (c-BN) and extra-diamond boron nitride (E-BN) has been synthesized at ambient pressure and room temperature by plasma electrolysis. The formation of c-BN was characterized by FTIR and TEM measurements. This method may not only offer a facile technique for c-BN production, but also provide a new research field in c-BN thermodynamics.

Ag2Se nanocrystals were rapidly synthesized by the sonochemical reaction between Ag ions and Se powders in diluted ammonia water. By using different complexing agents (NH3, citric acid or KSCN) in the reaction system, Ag2Se nano-spheres with different sizes were obtained. X-ray diffraction patterns showed that the samples obtained was orthorhombic β-Ag2Se. The morphology was characterized by scanning electron microscopy (SEM). This mild method may be extended to prepare other chalcogenides nanocrystalline at room temperature.

A novel method which is based on the hydrothermal reaction was employed to synthesize LiV3O8. First, the mixture solution of LiOH, V2O5, and NH4OH was subjected to the hydrothermal reaction. The hydrothermal treatment yielded a clear, homogeneous solution. The evaporation of this solution led to the formation of a precursor gel. The gel was then heated at different temperatures in the range of 300–600 °C. The characterization by X-ray diffraction (XRD), transmission electron microscopy (TEM), and Fourier transform infrared (FTIR) indicated that LiV3O8 nanorods have been obtained by this novel synthesis method. The electrochemical performance of the LiV3O8 nanorods have been investigated, which indicates that the highest discharge specific capacity of 302 mAh/g in the range of 1.8–4.0 V was obtained for the sample heated at 300 °C, and its capacity remained 278 mAh/g after 30 cycles.

Sized-controlled YVO4 nanoparticles have been synthesized by a simple microwave irradiation processing. The products were characterized by X-ray diffraction, transmission electron microscopy, and ultraviolet–visible spectroscopy. The results showed that the size of as-synthesized YVO4 powders was in the range of 5–18 nm and was extremely dependent on the solution pH value. The optical measurements displayed the obvious quantum-size effect of the products.

A solvothermal route has been adopted to prepare γ-LiV2O5 nanorods via the reaction of vanadium pentoxide (V2O5) and lithium hydrate (LiOH) in ethanol at 160–200 °C. The as-obtained products were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). The electrochemical performance of products as cathode active materials was investigated, which indicates that the nanorods of γ-LiV2O5 with smaller size showed better electrochemical properties.

A mild hydrothermal method has been adopted to prepare La0.5Sr0.5MnO3 and La0.5Ba0.5MnO3, which is of interest for a number of possible applications. The results from X-ray diffraction (XRD) indicate that in the present work the temperature of 200 and 240 °C are sufficient to prepare phase pure La0.5Sr0.5MnO3 and La0.5Ba0.5MnO3 crystals. At 200 °C, La0.5Sr0.5MnO3 nanowires are obtained. The average width and length of the nanowires are 40 nm and 4 μm, respectively. At 240 °C, La0.5Ba0.5MnO3 powders obtained have a cubic structure with the average size of 3–5 μm.

NiO films are prepared by sol–gel method. With the increasing of annealing temperature, the change from the amorphous to the crystalline nature of the NiO films is observed. Amorphous NiO films have higher electrochromic activity as well as poor reversibility. However, higher crystalline film annealed at 400 °C leads to better reversibility with lower optical modulation. The NiO film annealed at 350 °C exhibits noticeable electrochromic performance, such as the highest observed optical modulation of 50.7% at 550 nm, long-term durability, high coloration efficiency (71.4 cm2 C−1) and excellent reversibility (Qex/Qin = 92.3%).

The formation process of hydroxyfluorapatite under hydrothermal environment has been studied in detail. The fluoride ion has been substituted for the hydroxide ion in the OH lattice position, which has been characterized by X-ray diffraction (XRD) and FT–IR spectra. On the basis of the experimental results obtained from the transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM), a detailed four-step growth mechanism has been proposed for the formation of the 3D nanostructure, which involves the initial nucleation (conventional hydrothermal crystallization process), the self-assembly of nanoparticles (oriented attachment), the self-assembly of thin nanorods (oriented attachment) and the grain growth (Ostwald ripening).

A novel Co3O4/flocculent graphene (FG) hybrid on commercial Ni foam (NF) has been prepared. The unique flocculent graphene structure is prepared by combining a rapid filtering approach through Ni foam and a template method, in which the thermally expanded graphite is used as precursor and polystyrene (PS) microspheres are used as templates. The PS spheres play an important role in preventing the re-stacking of graphene nanosheets and the formation of flocculent graphene on NF. The PS spheres were first introduced as a guest material and were subsequently removed by calcination. The resulting free-standing FG/NF provides a three-dimensional and high conductivity scaffold for the hydrothermal growth of Co3O4 nanoclusters. The obtained Co3O4/FG/NF hybrid could be directly used as a binder-free supercapacitor electrode. Moreover, the Co3O4 nanoclusters on FG/NF scaffold exhibit improved specific capacitance of 1615 F g−1 compared to that of the bare NF. The 3D active material layer of Co3O4/FG/NF hybrid, high conductivity of 3D FG/NF scaffold and functional features of the Co3O4 nanocluster morphology synergistically result in an improved electrochemical performance.

A novel non-hydrazine precursor solution followed by dip-coating has been developed to produce Cu2ZnSnS4 (CZTS) and Cu2ZnSn(S,Se)4 (CZTSSe) thin films. The precursor solution is based on an ethanol solution of metal–thioacetamide (TAA) complex with monoethanolamine (MEA) as the additive agent. By forming coordination complexes with TAA, metal cations are found to have good solubility in ethanol–MEA solvents, producing molecular-level blending in metal precursor solutions. All the materials are low-cost and environmentally friendly. The annealing treatments are conducted under vacuum and Se vapor to form CZTS and CZTSSe absorber films. A solar cell fabricated with the CZTSSe thin film exhibits power conversion efficiency of 5.36%, which is much higher than that (2.86%) of the cell using the CZTS thin film as absorber.

Renewable nacre-like heparin (HEP)/layered double hydroxide (LDH) ultrathin films were first fabricated via a bottom-up layer by layer (LBL) deposition technique, which simultaneously showed largely enhanced mechanical properties and good blood compatibility. The results of UV-vis, FTIR, XRD and SEM analysis indicate that the HEP/LDH ultrathin films stacked densely together to form a well-defined brick-and-mortar structure. A strong electrostatic and hydrogen bond network at the organic–inorganic interface allowed the modulus of the film reach ca. 23 GPa, which was remarkably enhanced compared to previously reported polymer–LDH hybrid films. Due to the interlamellar heparin, the (HEP/LDH)n film may prove to be beneficial for new medical applications or as a replacement for conventional petroleum based plastics.

Although studies have been done on nitrogen doped carbon materials as lithium–oxygen (Li–O2) battery cathodes, few of them focus on the binder-free electrode structure, although they have been proved to bring improved performance. To fill this gap this work not only studies the nitrogen doped binder-free carbon cathode but also determines the performance of these cathodes with different levels of nitrogen doping. To make binder-free electrodes, these CNTs and N-CNTs were synthesized on nickel foam by a floating catalyst chemical vapor deposition method. The study found that the electrochemical performance of binder-free N-CNT cathodes in Li–O2 batteries improves as the level of nitrogen doping increases. To further study the reason why the electrodes with higher nitrogen amounts deliver better electrochemical properties, the morphology of discharge products on the different nanotubes are detected by scanning electron microscopy (SEM). The scan shows that the distribution of discharge products on the surface of CNTs become more and more uniform as the level of nitrogen doping increases and the discharge capacity and cycle performance are subsequently improved. Therefore, these binder-free N-CNT electrodes could be further explored as high capacity cathode materials for Li–O2 battery applications.