Search

The dendritic issue in aqueous zinc-ion batteries (ZBs) using neutral/mild electrolytes has remained an intensive controversy for a long time: some researchers assert that dendrites severely exist while others claim great cycling stability without any protection. This issue is clarified by investigating charge/discharge-condition-dependent formation of Zn dendrites. Lifespan degradation (120 to 1.2 h) and voltage hysteresis deterioration (134 to 380 mV) are observed with increased current densities due to the formation of Zn dendrites (edge size: 0.69-4.37 µm). In addition, the capacity is also found to remarkably affect the appearance of the dendrites as well. Therefore, at small current densities or loading mass, Zn dendrites might not be an issue, while the large conditions may rapidly ruin batteries. Based on this discovery, a first-in-class electrohealing methodology is developed to eliminate already-formed dendrites, generating extremely prolonged lifespans by 410% at 7.5 mA cm-2 and 516% at 10 mA cm-2 . Morphological analysis reveals that vertically aligned Zn dendrites with sharp tips gradually become passivated and finally generate a smooth surface. This developed electrohealing strategy may promote research on metal dendrites in various batteries evolving from passive prevention to active elimination, rescuing in-service batteries in situ to achieve elongated lifetime.

Prussian blue analogue (PBA)-type metal hexacyanoferrates are considered as significant cathodes for zinc batteries (ZBs). However, these PBA-type cathodes, such as cyanogroup iron hexacyanoferrate (FeHCF), suffer from ephemeral lifespan (≤1000 cycles), and inferior rate capability (1 A g-1 ). This is because the redox active sites of multivalent iron (Fe(III/II)) can only be very limited activated and thus utilized. This is attributed to the spatial resistance caused by the compact cooperation interaction between Fe and the surrounded cyanogroup, and the inferior conductivity. Here, it is found that high-voltage scanning can effectively activate the C-coordinated Fe in FeHCF cathode in ZBs. Thanks to this activation, the Zn-FeHCF hybrid-ion battery achieves a record-breaking cycling performance of 5000 (82% capacity retention) and 10 000 cycles (73% capacity retention), respectively, together with a superior rate capability of maintaining 53.2% capacity at superhigh current density of 8 A g-1 (≈97 C). The reversible distortion and recovery of the crystalline structure caused by the (de)insertion of zinc and lithium ions is revealed. It is believed that this work represents a substantial advance on PBA electrode materials and may essentially promote application of PBA materials.

Graphene as a coating material that shows high impermeability as an excellent barrier in oxidation and corrosion protection has been reported to be less stable at elevated temperature. Sometimes the formed galvanic cell between the graphene and protective surface will even increase the corrosion speed. In comparison, boron nitride (BN), which shows the same impermeability with graphene, is believed to be a better coating material with its superior thermal and chemical inertness. In this study, an in situ synthesis of BN coatings, grown by boron ink, on both carbon and Cu for anti-oxidation and anti-corrosion purposes has been demonstrated. Thermogravimetric analysis and electrochemical analysis reveal that the BN coatings can effectively prevent the carbon from being oxidized at high temperature in air and adequately slow down the corrosion rate of Cu in sodium chloride solution, respectively. These results indicate that boron ink assisted in situ BN coating has high potential in the applications of oxidation and corrosion protection.

We demonstrate the design and fabrication of novel hybrid nanoarchitectures using facile coating of ultrathin Ni(OH)2 nanosheets onto α-Fe2O3 nanowire arrays directly grown on Fe foils toward achieving high specific capacitance, high-energy and high power density, and long-term life supercapacitors. Well structured single-crystalline α-Fe2O3 nanowires uniquely served as cores that support redox active high surface area Ni(OH)2 shells and also contribute to specific capacitance as a conventional pseudocapacitive metal oxide. The Ni(OH)2@α-Fe2O3 hybrid composites exhibited excellent rate capability with specific energy of 22.8 Wh/kg and specific power of 16.4 kW/kg at a current density of 54.6 A/g, and excellent long-term cycling stability (keep over 85.7% of the initial specific capacitance after 5000 cycles). These results suggest that such hybrid composite architectures are very promising for the next generation of high-performance supercapacitors.

Nowadays, 2D nanosheets or nanoplatelets have attracted great attention due to their wide applications. However, the synthesis of 2D α-Fe2O3 nanosheets with well-defined hexagonal shape is extremely challenging, because the selective growth along one specific facet is very hard to be realized. In our work, we studied the non-capping ligand mediated reaction within graphene layer chamber, and successfully synthesized α-Fe2O3 hexagonal nanoplatelets sandwiched between graphene layers (HP-Fe–G). These materials exhibit an improved electrochemical performance compared with the pre-existing α-Fe2O3 nanoparticles loaded graphene (G-Fe2O3) composites because of the uniqueness of such architectures: thin nanoplatelets, large enough sandwiched spaces to buffer the volume expansion and N-doped graphene. HP-Fe–G delivered an ultrahigh reversible capacity of 1100 mAh/g after 50 cycles, thus higher than their theoretical value (926 mAh/g); while G-Fe2O3 composites showed relatively low capacity retention even after only 20 cycles (582 mAh/g). In addition, HP-Fe–G also reveal superior rate capability, 887 mAh/g at 1C; in comparison, this value was only 135 mAh/g at 1C for G-Fe2O3.

Mechanical properties and fracture behaviors of multiwalled WS2 nanotubes produced by large scale fluidized bed method were investigated under uniaxial tension using in situ transmission electron microscopy probing; these were directly correlated to the nanotube atomic structures. The tubes with the average outer diameter ∼40 nm sustained tensile force of ∼2949 nN and revealed fracture strength of ∼11.8 GPa. Surprisingly, these rather thick WS2 nanotubes could bear much higher loadings than the thin WS2 nanotubes with almost "defect-free" structures studied previously. In addition, the fracture strength of the "thick" nanotubes did not show common size dependent degradation when the tube diameters increased from ∼20 to ∼60 nm. HRTEM characterizations and real time observations revealed that the anomalous tensile properties are related to the intershell cross-linking and geometric constraints from the inverted cone-shaped tube cap structures, which resulted in the multishell loading and fracturing.

Layered boron nitrides (BNs) are usually viewed as excellent protective coatings and reinforcing materials due to their chemical inertness and high mechanical strength. However, the attention paid to their potential applications in gas sorption, especially in case of hydrogen, has obviously been insufficient. Herein, a novel BN material (i.e., porous microbelts), with the highest specific surface area ever reported for any BN system, up to 1488 m² g⁻¹, is obtained through one-step template-free reaction of a boron acid-melamine precursor with ammonia. Comprehensive high-resolution transmission electron microscopy, X-ray diffraction, and Raman characterizations all confirm that the obtained BN phase is partially disordered, shows an enlarged average spacing between adjacent (0002) layers (d₀₀₀₂ = 0.38 nm, compared to normal 0.33 nm for a bulk layered BN), and belongs to an intermediate state between hexagonal (h-BN) and amorphous (a-BN) phases. By changing the synthesis temperatures, the textures of obtained porous microbelts are adjustable. H₂ sorption evaluations demonstrate that the materials exhibit high and reversible H₂ uptake from 1.6 to 2.3 wt % at 77 K and at a relatively low pressure of 1 MPa.

Multifunctional energy storage and conversion devices that incorporate novel features and functions in intelligent and interactive modes, represent a radical advance in consumer products, such as wearable electronics, healthcare devices, artificial intelligence, electric vehicles, smart household, and space satellites, etc. Here, smart energy devices are defined to be energy devices that are responsive to changes in configurational integrity, voltage, mechanical deformation, light, and temperature, called self-healability, electrochromism, shape memory, photodetection, and thermal responsivity. Advisable materials, device designs, and performances are crucial for the development of energy electronics endowed with these smart functions. Integrating these smart functions in energy storage and conversion devices gives rise to great challenges from the viewpoint of both understanding the fundamental mechanisms and practical implementation. Current state-of-art examples of these smart multifunctional energy devices, pertinent to materials, fabrication strategies, and performances, are highlighted. In addition, current challenges and potential solutions from materials synthesis to device performances are discussed. Finally, some important directions in this fast developing field are considered to further expand their application.

A highly durable high-performance all-polymer micro-supercapacitor with plug-and-play function is developed. Through the newly developed technology, these micro-supercapacitors can be transferred to any substrate with all functions well retained.

The fabrication of photoluminescent Ti

Polypyrrole (PPy), as one of the conducting polymers, has emerged as a promising active material for high performance supercapacitor owing to its intrinsic characteristics ( e.g. high electrical conductivity and interesting redox properties). It’s attracting more and more attentions with the development of flexible/wearable devices thanks to the great flexibility and ductility of PPy as a polymer. This review presents a comprehensive understanding on synthesis, morphology control, electrochemical performances and solid-state devices of the nanostructured PPy and its nanocomposites. In the past decades, a variety of nanostructures, including one-, two-, and three-dimensional, have been designed and fabricated via different methods, demonstrating a great potential for the application as supercapacitor electrodes. Thereafter, many nanostructured PPy-based supercapacitors with different macroscopic configurations have been presented aiming to achieve better electrochemical performance, and some representative ones, for example, flexible and/or wearable supercapacitors, are summarized in this review. Cycling stability is another critical issue that determines its practicability of the PPy-based devices. Solutions to improve cycling performance and mechanisms behind are also discussed. Last, perspectives for the future development in nanostructured PPy-based supercapacitors are described. This review gives a summary of selected contributions which we hope to provide readers with a better understanding of the fast developing field of PPy-based supercapacitors.

Multifunctional energy storage and conversion devices that incorporate novel features and functions in intelligent and interactive modes, represent a radical advance in consumer products, such as wearable electronics, healthcare devices, artificial intelligence, electric vehicles, smart household, and space satellites, etc. Here, smart energy devices are defined to be energy devices that are responsive to changes in configurational integrity, voltage, mechanical deformation, light, and temperature, called self-healability, electrochromism, shape memory, photodetection, and thermal responsivity. Advisable materials, device designs, and performances are crucial for the development of energy electronics endowed with these smart functions. Integrating these smart functions in energy storage and conversion devices gives rise to great challenges from the viewpoint of both understanding the fundamental mechanisms and practical implementation. Current state-of-art examples of these smart multifunctional energy devices, pertinent to materials, fabrication strategies, and performances, are highlighted. In addition, current challenges and potential solutions from materials synthesis to device performances are discussed. Finally, some important directions in this fast developing field are considered to further expand their application.

An ultimate integration strategy making use of material and geometry is applied in a proof-of-concept study. Integrated supercapacitor-sensor systems with the capability of photodetecting and strain sensing are fabricated based on multifunctional conducting polypyrrole and piezoresistive textile geometry, respectively. This integration strategy enables promising applications for self-powered smart sensory, wearable and healthcare electronics.

The cycling stability of flexible supercapacitors with conducting polymers as electrodes is limited by the structural breakdown arising from repetitive counterion flow during charging/discharging. Supercapacitors made of facilely electropolymerized polypyrrole (e-PPy) have ultrahigh capacitance retentions of more than 97, 91, and 86% after 15000, 50000, and 100000 charging/discharging cycles, respectively, and can sustain more than 230000 charging/discharging cycles with still approximately half of the initial capacitance retained. To the best of our knowledge, such excellent long-term cycling stability was never reported. The fully controllable electropolymerization shows superiority in molecular ordering, favoring uniform stress distribution and charge transfer. Being left at ambient conditions for even 8 months, e-PPy supercapacitors completely retain the good electrochemical performance. The extremely stable supercapacitors with excellent flexibility and scalability hold considerable promise for the commerical application of flexible and wearable electronics.

As the devices and components in the microelectronic systems are getting more and more miniaturized and integrated, thermal management becomes a critical issue in realizing assembling high power, multifunctional, and high reliability systems. Thermally conductive polymer composites play a very important role in thermal management. They can be thermal interface materials (TIMs) and electronic packaging materials. One important category of these materials is electrically insulating but thermally conductive polymer composites, which can be used to conduct heat but keep the devices being electrically insulated. Great efforts have been made on fabricating high thermal conductive insulating polymer composites and different fillers, mainly some oxides and nitrides have been adopted by researchers. However, the high thermal conductivity of the polymer composites may be affected by many factors, including intrinsic thermal conductivity of the fillers, aspect ratio of the fillers, processing methods, etc. In this chapter, we will review the current progresses of the thermally conductive electrically insulating polymer composites with introduction to various types of inorganic fillers and the factors that influence the thermal conductivity achieved in the composites.

Chemical approaches for the functionalization of boron nitride nanotubes (BNNTs) are discussed, including covalent functionalization, noncovalent functionalization, defect reaction, and inner filling BNNTs, in regards of the multiple utility of these approaches for improving the availability of BNNTs as innovative biomaterials, by integrating new functions and properties toward several applications in nanobiomedicine.

We report the experimental and theoretical study of boron nitride nanotube (BNNT) torsional mechanics. We show that BNNTs exhibit a much stronger mechanical interlayer coupling than carbon nanotubes (CNTs). This feature makes BNNTs up to 1 order of magnitude stiffer and stronger than CNTs. We attribute this interlayer locking to the faceted nature of BNNTs, arising from the polarity of the B-N bond. This property makes BNNTs superior candidates to replace CNTs in nanoelectromechanical systems (NEMS), fibers, and nanocomposites.

Dielectric polymer composites with high thermal conductivity are very promising for microelectronic packaging and thermal management application in new energy systems such as solar cells and light emitting diodes (LEDs). However, a well-known paradox is that conventional composites with high thermal conductivity usually suffer from the high dielectric constant and high dielectric loss, while on the other hand, composite materials with excellent dielectric properties usually possess low thermal conductivity. In this work, an ideal dielectric thermally conductive epoxy nanocomposite is successfully fabricated using polyhedral oligosilsesquioxane (POSS) functionalized boron nitride nanotubes (BNNTs) as fillers. The nanocomposites with 30 wt% fraction of POSS modified BNNTs exhibit much lower dielectric constant, dielectric loss tangent, and coefficient of thermal expansion in comparison with the pure epoxy resin. As an example, below 100 Hz, the dielectric loss of the nanocomposites with 20 and 30 wt% BNNTs is reduced by one order of magnitude in comparison with the pure epoxy resin. Moreover, the nanocomposites show a dramatic thermal conductivity enhancement of 1360% in comparison with the pristine epoxy resin at a BNNT loading fraction of 30 wt%. The merits of the designed composites are suggested to originate from the excellent intrinsic properties of embedded BNNTs, effective surface modification by POSS molecules, and carefully developed composite preparation methods.

Boron nitride nanotube (BNNT)/aluminum matrix composite nanohybrids were fabricated through magnetron sputtering of Al onto dispersed multiwalled BNNTs with average external diameters of 40-50 nm. Aluminum phase coating tightly wrapped the BNNTs after the deposition. The coating thickness in the range of 5-200 nm was controlled by changing sputtering time. Using imaging techniques and electron diffraction analysis in a transmission electron microscope, the Al phase was found to create nanocrystalline shields around individual BNNTs. The chemical states of the hybrid nanomaterials during the initial stages of sputtering were analyzed by X-ray photoelectron spectroscopy. Direct in situ bending and tensile tests on individual BNNT-Al nanocomposites were carried out by using a dedicated transmission electron microscope-atomic force microscope holder. In parallel, high-resolution TEM images and video recordings were taken for the analysis of deformation kinetics and fracture mechanisms. The nanohybrids with a suitably thick aluminum coating (similar to 40 nm) withstood at least nine times higher stresses compared to a pure non-armed Al metal. This pioneering work opens up a prospective pathway for making ultralight and superstrong "dream" structural materials for future automotive and aerospace applications. (C) 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Inspired by opening soft drink cans, a one-pot method to prepare ZnO hollow spheres with double-yolk egg (DEH) architectures is developed. The bubble-assisted Ostwald ripening is proposed for the formation of these novel structures. Uniqueness of DEHs morphology led to greatly enhanced photocatalytic activity and photodetector performance. The newly developed synthetic concept and the obtained novel morphologies should pave the way towards the design and fabrication of other similar materials with enhanced properties for microelectronics, optoelectronics, and other applications.

In this review, a concise research history of low-dimensional boron nitride (BN) nanomaterials followed by recent developments in their synthesis, morphology, properties, and applications are presented. Seventeen years after the initial synthesis of BN nanotubes, research on BN nanomaterials has developed far enough to establish them as one of the most promising inorganic nanosystems. In this regard, it is envisaged that the unique properties of low-dimensional BN systems, such as superb mechanical stiffness, high thermal conductivity, wide optical bandgap, strong ultraviolet emission, thermal stability and chemical inertness will play a key role in prospective developments.

We report that efficiently disentangled boron nitride nanotubes (BNNTs) can be obtained due to functionalization in an aqueous solution with a natural water-soluble polysaccharide, gum arabic (GA). An atomic force microscopy study showed excellent dispersion of GA-functionalized BNNTs in the aqueous phase. Fluorescent, ultraviolet, and infrared absorption spectroscopies revealed the strong interactions between GA and the sidewalls of BNNTs. Subsequently, several functional proteins were successfully immobilized onto the surfaces of GA-functionalized BNNTs via strong electrostatic interactions under suitable pH conditions.

Nanomaterials with layered structures, with their intriguing properties, are of great research interest nowadays. As one of the primary two-dimensional nanomaterials, the hexagonal boron nitride nanosheet (BNNS, also called white graphene), which is an analogue of graphene, possesses various attractive properties, such as high intrinsic thermal conductivity, excellent chemical and thermal stability, and electrical insulation properties. After being discovered, it has been one of the most intensively studied two-dimensional non-carbon nanomaterials and has been applied in a wide range of applications. To support the exploration of applications of BNNSs, exfoliation, as one of the most promising approaches to realize large-scale production of BNNSs, has been intensively investigated. In this review, methods to yield BNNSs by exfoliation will be summarized and compared with other potential fabrication methods of BNNSs. In addition, the future prospects of the exfoliation of h-BN will also be discussed.

Hematite (α-Fe2O3) crystals with uniform size and structure are synthesized through very facile one-pot hydrothermal methods without any additive. The as-synthesized sub-micrometer-sized α-Fe2O3 crystals with small surface areas perform superb visible light photodegradation activities, even much better than most other α-Fe2O3 nanostructures with large surface areas. Profound mechanism analyses reveal that the microwave-assisted hydrothermal (Mic-H) synthesized α-Fe2O3 is enclosed by 12 high-index {2-15} facets. The structure and the low unoccupied molecular orbital (LUMO) of the high-index planes result in the excellent photocatalytic activity. This is the first report on the formation of {2-15} plane group of hematite, and the synthesis of the hematite particles with the {2-15} planes is very simple and no any facet-controlling agent is used. This study may pave the way to further performance enhancement and practical applications of the cheap hematite materials.

We report that nucleotides disentangle and disperse multiwalled boron nitride nanotubes in aqueous solution via π–π stacking interactions. Quantum dot-boron nitride nanotube hybrid materials were produced by using guanosine 5′-monophosphate as a linking reagent. These hybrid materials are highly promising for biomedical imaging technologies.

The growth, structure, and properties of two-dimensional boron nitride (BN) nanostructures synthesized by a thermal chemical vapor deposition method have been systematically investigated. Most of the BN nanosheets (BNNSs) were less than 5 nm in thickness, and their purity was confirmed by X-ray energy dispersive spectroscopy, X-ray photoelectron spectroscopy, electron energy loss spectroscopy, and Raman spectroscopy. The effects of the process variables on the morphology and roughness of the coatings were studied using atomic force microscopy and scanning electron microscopy. A smooth BN coating was obtained at 900 °C, while compact BNNS coatings composed of partially vertically aligned nanosheets could be achieved at 1000 °C and higher temperatures. These nanosheets were mostly separated and exhibited high surface area especially at higher synthesis temperatures. The nonwetting properties of the BNNS coatings were independent of the water pH and were examined by contact angle goniometry. The present results enable a convenient growth of pure BNNS coatings with controllable levels of water repellency, ranging from partial hydrophilicity to superhydrophobicity with contact angles exceeding 150°.

We report for the first time how boron nitride (BN) nanotubes and nanospheres may effectively be used to achieve remarkable thermal conductivity improvement of a fluid. Benefiting from high thermal conductivity and high-aspect-ratio of BN nanotubes, at a fraction of 6 vol %, the thermal conductivity of water was remarkably improved, up to ∼2.6-times. With BN nanospheres as fillers, the viscosity of the fluid can be kept decently low and thermal conductivity can also be effectively improved. A combination of BN nanotubes and nanospheres was found to increase the fluid's thermal conductivity while keeping its viscosity low, thus, such mixtures can be promising fillers for highly thermo-conductive fluids. Finally, calculations based on finite element method were used to investigate the regarded nanofluids. On the basis of the results, thermal conductivity was estimated to be more than, or close to 200 W/mK for BN nanotubes and nanospheres, respectively.

Multiwalled boron nitride nanotubes (BNNTs) functionalized with Fe(3)O(4) nanoparticles (NPs) were used for arsenic removal from water solutions. Sonication followed by a heating process was developed to in situ functionalize Fe(3)O(4) NPs onto a tube surface. A batch of adsorption experiments conducted at neutral pH (6.9) and room temperature (25 degrees C) and using the developed nanocomposites revealed effective arsenic (V) removal. The Langmuir, Freundlich, and Dubinin-Radushkevich adsorption isotherms were measured for a range of As(V) initial concentrations from 1 to 40 mg/L under the same conditions. The equilibrium data well fitted all isotherms, indicating that the mechanism for As(V) adsorption was a combination of chemical complexation and physical electrostatic attraction with a slight preference for chemisorption. The magnetite NPs functionalized on BNNTs led to a simple and rapid separation of magnetic metal-loaded adsorbents from the treated water under an external magnetic field.

We report on the basic physical quantities of boron nitride nanotubes (BNNTs), namely specific heat capacity and density, which have not been measured to date. A series of differential scanning calorimetry experiments were performed, and specific heat capacity was calculated for multi-walled BNNTs synthesized by chemical vapor deposition using boron and metal oxide as precursor. Very close specific heat capacity values were revealed for BNNTs and a BN powder of hexagonal (h-BN) phase. Densities of BNNTs were measured through density analyses of their epoxy composites. Our work is important as far as bulk properties of large amounts of BNNTs are crucial, for example, thermal property and density prediction for composite materials with BNNTs embedded.

We report a study on the optical luminescence properties and the electronic structures of boron nitride nanotubes (BNNTs). BNNTs with natural B (80% (11)B and 20% (10)B) and pure (10)B are investigated in comparison with hexagonal BN crystals using X-ray absorption near-edge structures (XANES) and X-ray excited optical luminescence (XEOL). We find that the BNNT specimen synthesized with natural B contains more oxide impurities than that with pure (10)B, resulting in significantly different behavior in optical luminescence. All BN samples with hexagonal structures are found to emit strong luminescence, but the emission spectra are strongly morphology- and structure-dependent. XEOL and XANES measurements were carried out at the B K-edge, N K-edge, and O K-edge in order to reveal the origin of different luminescence channels and the corresponding electronic structures in these BN materials.

There is a growing demand for flexible and wearable energy devices. How to enhance their tolerance to various mechanical stresses is a key issue. Bending, stretching, or twisting of flexible batteries has been widely researched. However, shear force is inevitably applied on the batteries during stretching, bending, and twisting. Unfortunately, thus far, research on analyzing shear resistance of solid batteries or even enhancing the shear tolerance has never been reported. Herein, a sewable Zn-MnO2 battery based on a nanofibrillated cellulose (NFC)/ployacrylamide (PAM) hydrogel, electrodeposited Zn nanoplates anode, and carbon nanotube (CNT)/α-MnO2 cathode is reported. The designed NFC/PAM hydrogel exhibits a relatively high mechanical strength with a large stretchability; the preformed NFC bone network stabilizes the large pores as channels for electrolyte diffusion. Furthermore, the effect of sewing on enhancing the shear resistance of the solid batteries is analyzed. The sewed Zn-MnO2 battery retains 88.5% of its capacity after 120 stitches, and withstands a large shear force of 43 N. The sewable and safe Zn-MnO2 is also able to be designed into a skirt and put on a toy as an energy source to power a red light emitting diode.

Herein the recent experiments performed by the authors on fabricated multi-walled BN nanotubes and monoatomic BN graphene-like nanosheets are reviewed. The results are presented in several sections, namely: (i) method for high-yield synthesis of thin, defect-free BN nanotubes of only a few-layers, with external diameters below 10 nm; (ii) verification of BN nanotube piezoelectrical behavior and its electrically-induced thermal decomposition under combined resistive heating and electrical charging in a transmission electron microscope; (iii) the first direct measurements of the true tensile strength and Young’s modulus of BN nanotubes, using newly developed nanotensile tests inside an electron microscope; the measured values were found to be ∼30 GPa and ∼900 GPa, respectively; and (iv) diverse kinetic processes taking place within the prepared monoatomic BN sheets (so-called “white graphenes”) affiliated with intensive knock-on B and N atom displacements under high energy electron beam irradiation in an aberration-corrected medium-voltage high-resolution transmission electron microscope.