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Solar-thermal energy storage using latent heat of phase change materials (PCMs) offers renewable penetration in wide range of smart applications. The limiting solar energy harvesting efficiency of existing photo-thermal dopant materials and their negative impact on thermal storage capacity have remained fundamental impediment to further advancement. Herein, we explore a phosphorene based bandgap engineered broadband photonic nanoheater for efficient thermal charging of solid-solid PCMs. In our devised composite system, we benefitted from the synergistic effect of highly efficient photonic energy harvesting characteristic of exfoliated phosphorene nanoflakes (PNF) and latent heat storage capability as well as encapsulating feature of PCM matrix. The solar-thermal energy storage efficiency of our developed materials exceeds 95 % even at lower phosphorene doping level (1 wt. %) and under full solar spectrum with improved latent heat storage capacity (150 J g−1). The achieved efficiency is highest among all photo-thermal storage materials and attributed to the intense and broadband solar absorbance of PNF featured by wide thickness distribution. Further, coating of developed solar heat storage material on fabric substrate has shown promising results toward real world applications.

A novel solid-to-solid phase change composite brick was prepared by combination of polyurethane (PU) and pitch-based graphite foam (PGF). The carbonaceous support, which can be used for mass production, not only greatly improves the thermal conductivity but promote electro-to-heat conversion efficiency of organic phase change materials (PCMs). Our composite retained the enthalpy of PCM and exhibited a greatly reduced supercooling temperature. The novel composite was investigated by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and scanning electron microscope (SEM). The enthalpy of polyurethane has increased about 8.6% after infiltrating into graphite foam. The composite was very stable during thermal cycle test, and the electro-to-heat conversion efficiency achieves to 85% at lower voltages (1.5–1.8 V), which can vastly reduce energy consumption. The as-prepared composite was used in a wear layer to test its performance comparing with normal fabric.

Owing to the high energy density of phase change materials, latent heat storage systems have been an effective strategy for the improvement of energy efficiency. The severe limitations of their extensive application are the potential leakage and low thermal conductivity. Herein, we developed a facile dual-encapsulation method to solve the abovementioned problems in the phase change composite composed of octadecanol, a high thermal/electrical conductive macroporous graphite foam and a thin waterborne polyurethane (WPU) film. After dual-encapsulation, the thermal conductivity of the composite was 20 times higher than that of pure phase change material (PCM) octadecanol. As a result, the composite exhibited a reduced supercooling degree and rapid thermal energy charging behaviors, as well as electro-to-heat conversion ability. This study gives a new perspective for the synergistic enhancement of both the thermal and electric conductivity of functional PCMs for thermal energy storage and conversion.

Organic phase change materials (PCMs) have exhibited many promising potentials for thermal energy conversion and storage, but they are still confronted with many technical bottlenecks for practical application, such as low conductivity, leakage during phase transition process, and lack of functionality. In this article, a highly-efficient electro/photo to heat conversion system of polyurethane@graphite foam (PU@GF) phase change composites was successfully fabricated through in situ polymerization of polyethylene glycol (PEG) in GF. The obtained PU presents solid–solid phase transition behavior that is different from the solid–liquid phase change of original PEG, which can prevent PU from leakage even if it was loaded in micrometer pores in the GF during application. On the other side, PU can improve the thermal stability and decrease the overcooling degree of the composites in effect. Excellent conductive network was provided by the GF, with which the light absorption and thermal conductivity of the composites were enhanced dramatically. Consequently, the solid–solid phase change composites can effectively store electricity or sunlight energy. The electro-heat storage efficiency of the composites can exceed 80% at 1.2 or 1.4 V, meanwhile, the photo-heat storage efficiency can close to 67% under simulated solar illumination. This result presents the highest efficiency for electro-to-heat conversion by PCMs techniques driven by a quite low voltage up to now, and will give rise to a new expectation of functional PCM application for energy conversion and storage.

A high voltage pulsed electrochemical deposition (50 Hz, −50 V) technique was used to synthesize CoFex (x=1.57, 2.02) nanowire arrays in anodic aluminum oxide templates. The nanowire arrays (NA) are different in diameter (NA A, 40 nm; NA B, 50 nm), center-to-center distance (NA A, 60 nm; NA B, 100 nm) and length (NA A, 4 μm; NA B, 8 μm). Microstructural characterization shows high crystallinity of the formed nanowires. The magnetic measurements indicate that the nanowire arrays possess uniaxial anisotropy with the easy magnetization axis along the nanowire. When magnetic field is applied in this direction, the coercivities of both nanowire arrays are larger than 1600 Oe. The shape difference between two magnetization hysteresis loops is due to dipolar magnetostatic interaction, and analytical calculation is performed to interpret the magnetic properties as a function of the wire geometry. The results suggest that during high voltage electrodeposition, reduced atoms are highly energetic and the crystallographic growth planes can be (110), (111) and (211).

As we know, Li(+)-ion transport in layered LiNi1/3Co1/3Mn1/3O2 (NCM) is through two-dimensional channels parallel to the Li(+)-ion layers that are indexed as {010} active planes. In this paper, NCM nanoplates with exposed {010} active facets are synthesized in a polyol medium (ethylene glycol) and characterized by XRD, XPS, SEM, and HR-TEM. In addition, the effects of reaction conditions on the morphologies, structures and electrochemical performances are also evaluated. The results show that more {010} facets can be exposed with the thickness of NCM nanoplates increasing which can lead to more channels for Li(+)-ion migration. However, when the annealing temperatures exceed 900 °C, many new crystal planes grow along the thickness direction covering the {010} facets. In all of the NCM nanoplates obtained at different conditions, the NCM nanoplates calcined at 850 °C for 12 h (NCM-850-12H) display a high initial discharge capacity of 207.6 mAh g(-1) at 0.1 C (1 C = 200 mA g(-1)) between 2.5 and 4.5 V higher than most of NCM materials as cathodes for lithium ion batteries. The discharge capacities of NCM-850-12H are 169.8, 160.5, and 149.3 mAh g(-1) at 2, 5, and 7 C, respectively, illustrating the excellent rate capability. The superior electrochemical performance of NCM-850-12H cathode can be attributed to more {010} active planes exposure.

Mesoporous carbon nanosheets (MCNSs) of 40 nm thickness and 10 μm width have been prepared. Dense mesopores with an average size of 9 nm were distributed in a disorderly manner throughout the nanosheets. Anodes made from MCNSs and applied in lithium-ion batteries delivered superior rate performances and stable cycle life.

Here we report catalyst-free combined synthesis of metal/semiconductor Zn/ZnO core/shell microspheres with hollow interiors on Si substrate and metallic Zn polygonal microparticles on glass substrate in a single experiment via thermal evaporation and condensation technique using nitrogen (N 2 ) as carrier agent at 800 °C for 120 min. The Zn/ZnO hollow microspheres were observed to have dimensions in the range of 70–80 μm whereas metallic Zn microparticles with polygonal cross section and oblate spherical shape were found to be of 8–10 μm. Some of the Zn/ZnO core/shell hollow spheres were also observed to have single crystalline ZnO pointed rods in extremely low density grown on the outer shell. The structural, compositional and morphological characterization of the products obtained on the substrates were performed by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and selected area electron diffraction (SAED). A vapor–liquid–solid (VLS) process based growth mechanism was proposed for the formation of Zn/ZnO core/shell microspheres with hollow interior. The optical properties of Zn/ZnO core/shell microspheres were investigated by measuring the photoluminescence (PL) spectra at room temperature (RT). Two very strong emission bands were observed at 373 and 469 nm in the ultraviolet and visible regions respectively under excitation wavelength of 325 nm. Also the effect of the various excitation wavelengths on the PL behaviour was studied at room temperature. PL studies of Zn/ZnO core/shell microspheres show the promise of the material for applications in UV and blue light optical devices.

Phase transition is a natural phenomenon happened around our daily life, represented by the process from ice to water. While melting and solidifying at a certain temperature, a high heat of fusion is accompanied, classified as the latent heat. Phase change material (PCM) has been widely applied to store and release large amount of energy attributed to the distinctive thermal behavior. Here, with the help of nanoporous materials, we introduce a general strategy to achieve the binary eicosane/PEG4000 stuffed reduced graphene oxide aerogels, which has two ends with different melting points. It's successfully demonstrated this binary PCM composites exhibits thermal rectification characteristic. Partial phase transitions within porous networks instantaneously result in one end of the thermal conductivity saltation at a critical temperature and therefore switch on or off the thermal rectification with the coefficient up to 1.23. This value can be further raised by adjusting the loading content of PCM. The uniqueness of this device lies in its performance as a normal thermal conductor at low temperature, only exhibiting rectification phenomenon when temperature is higher than a critical value. The stated technology has broad applications for thermal energy control in macroscopic scale such as energy-efficiency building or nanodevice thermal management.

A simple electrochemical corrosion synthesis route using hot and concentrated alkaline aqueous solution is demonstrated for the first time to fabricate high yield crystalline magnetite mesocrystal microdisks without adding any organic additives. According to the results of time-dependent experiments, the self-assembly mechanism of mesocrystals is revealed as crystallization–dissolution–recrystallization. The mesocrystals with large sizes of 30 μm show hierarchical architectures. They are piled up with several thin layers and each layer is composed of small nanoparticles with an average size of 20 nm. Moreover, room temperature ferrimagnetic behavior with large coercivity value of 182.88 Oe (∼0.01829 T) is recorded.

LiNi1/3Co1/3Mn1/3O2 hollow nano-micro hierarchical microspheres (NCM-HS) are synthesized using MnCO3 both as a self-template and Mn source. The hollow microspheres with diameters of about 1 μm have walls about 250 nm thick, which are composed of approximately 100 nm primary nanoparticles. NCM-HS cathodes have an initial discharge capacity of 212 mA h g−1 at 0.1 C between 2.5 and 4.5 V. After 40 charge–discharge cycles, the capacity retention at 0.1 C is 85.1%. At higher rates, the reversible capacities of the NCM-HS cathodes are 208.9 (0.5 C), 204.8 (1 C), 180.7 (2 C), 155.7 (5 C) and 135.9 mA h g−1 (10 C). The high performances can be attributed to the distinctive hollow microspherical structures with the 100 nm building blocks, which could effectively reduce the path of Li ion diffusion, increase the contact area between electrodes and electrolyte and buffer the volume changes during the Li ion intercalation/deintercalation processes.

We synthesized unexplored activator-Fe doped silicon oxynitride microwires by a simple CVD method. This microwire can generate SPP when induced by photons/electrons. It exhibits three significant features, a stable emission peak, the ability to act as a plasmon nonlinear laser and displays mutual light beams interference. The absorption and external quantum efficiency of the Fe doped silicon oxynitride are 73.2% and 51.8%, respectively. Upon controlling the O/N ratio, the emission band can be tuned from 670 nm to 735 nm.

We have utilized the lattice mismatch between two adjacent nanocrystals in polycrystalline BFO ceramics to introduce a layer of highly strained BFO phase by taking advantage of crystal growth course. Therefore, a spin-valve like structure has been fabricated that consists of ferromagnetic phase (highly strained BFO phase)/antiferromagnetic phase (bulk BFO nanoparticles), without any substrates or alloy layers. BFO ceramics can present an exchange biasing effect ((|HEB|) ∼ 36 Oe) with an enhanced magnetic moment (Ms ∼ 0.11 μB Fe−1) and in addition saturated polarization (2Pr ∼ 57.4 μC cm−2) at room temperature. A low working electric field (Ec ∼ 4.8 kV cm−1) shows an advantage of low energy consumption in application. These results imply that there is potential for room temperature applications of single phase BFO with exchange biasing, enhanced magnetization and saturated polarization.

This paper reports on the non-traditional corrosion method for the synthesis of hematite mesocrystals in the size range of 30 μm. The results clearly show that the self-assembly of hematite mesocrystals were consisted of many small building units which were densely packed. The formation mechanism for hematite mesocrystals is proposed, which belongs to nonclassical crystallization. Ammonium chloride (NH4Cl), as a reagent in the reaction, has played a key role in the formation of hematite mesocrystals. The high coercivity of hematite mesocrystals of 4437.80 Oe was recorded. The origin of the large coercivity is also discussed. The size of the building units is the main reason, the anisotropies of the mesocrystals, defects, strain and exchange coupling are attributed to the enhancement of the large coercivity. All of the reasons for the explanation of the large coercivity can be attributed to the presence of N. The synthesis route is economical and environmentally friendly and is a promising way to fabricate other kinds of mesocrystals.