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Two-dimensional sheets of hexagonal ( ##IMG## [http://ej.iop.org/images/2053-1583/6/4/045028/tdmab33baieqn001.gif] —form) antimonene have been epitaxially prepared on Pb(1 1 1) ultrathin films (quantum wells) grown on Si(1 1 1)(6 ##IMG## [http://ej.iop.org/images/2053-1583/6/4/045028/tdmab33baieqn002.gif] 6)Au. Scanning tunneling microscopy reveals two different moiré structures with wavelength of 2.3 nm and 3.8 nm on antimonene-covered surface. Ab initio density functional theory predicts the antimonene-substrate separation of 0.37 nm, that classifies this system as a van der Waals heterostructure. Despite such large separation, scanning tunneling spectroscopy evidences quantum well states in the antimonene layer too. A method of engineering of antimonene electronic band structure by means of quantum size effect has been proposed. The present work is the first experimental realization of ##IMG## [http...]

Black phosphorus captures enormous research attention on the anisotropic properties due to its orthorhombic crystal structure. Here the in-plane anisotropic thermoelectric behaviors of bulk black phosphorus crystals in the temperature range from 300 K to 600 K are reported for the first time. Based on the home-grown big size and high-quality black phosphorus crystals, the electrical conductivity and Seebeck coefficient are simultaneously measured by a ZEM-3 instrument system, and the thermal conductivity is measured by time-domain thermoreflectance (TDTR). For each individual parameter, the values along the zigzag and armchair directions show the same temperature-dependent trend. However, the electrical conductivity along the armchair direction is ~ two times of that along the zigzag direction, while the thermal conductivity along the armchair direction is only ~ one third of that along the zigzag direction. Furthermore, the Seebeck coefficients show almost isotropic behavior. A...

Nature Nanotechnology, Published online: 08 July 2019; doi:10.1038/s41565-019-0489-8

Colossal magneto-optical activity on Landau levels in the mid-infrared and terahertz ranges is observed in high-mobility encapsulated graphene.

Two-dimensional (2D) layered materials have attracted intensive interests in the past decade. Their unique electronic, magnetic, optical, and mechanical properties render broad applications in various fields. Stability of these ultrathin materials has to be delicately considered because their structures and properties are subject to ambient conditions. In this work, we review the chemical and structural stabilities of versatile 2D layered materials, and summarize the ways to modify the materials for the enhancement of their stabilities. Our review not only provides deep understandings of the stability of 2D materials, but may inspire new ideas to improve the reliability and durability of related devices.

We carried out point contact (PC) investigation of WTe 2 single crystals. We measured Yanson PC spectra ( d 2 V / dI 2 ) of the electron–phonon interaction (EPI) in WTe 2 . The PC spectra demonstrate a main phonon peak around 8 meV and a shallow second maximum near 16 meV. Their position is in line with the calculation of the EPI spectra of WTe 2 in the literature, albeit phonons with higher energy are not resolved in our PC spectra. An additional contribution to the spectra is present above the phonon energy, what may be connected with the peculiar electronic band structure and need to be clarified. We detected tiny superconducting features in d 2 V / dI 2 close to zero bias, which broadens by increasing temperature and blurs above 6 K. Thus, (surface) superconductivity may exist in WTe 2 with a topologically nontrivial state. We found a broad maximum in dV

We developed a comprehensive theoretical framework focusing on many-body effects of exciton species in monolayer WS 2 , including bright and dark excitons, and intra- and inter-valley biexcitons, to investigate valley dynamics in monolayer WS 2 subjected to a tilted magnetic field ##IMG## [http://ej.iop.org/images/2053-1583/6/4/045014/tdmab2cf7ieqn001.gif] . In particular, the evolution of the exciton population densities and the many-body particle scatterings are considered to calculate the valley polarization ( ##IMG## [http://ej.iop.org/images/2053-1583/6/4/045014/tdmab2cf7ieqn002.gif] ) as a function of the magnetic field. We found valley splittings for the dark exciton and biexciton energy levels that are larger than those of bright excitons, of  −0.23 meV T −1 . For example, −0.46 meV T −1 for dark excitons and  −0.69 meV T −1 for bright-dark intra-valley biexcitons. Furthermore,...

We demonstrate the soft realization of a new generation of functional hybrid van der Waals (vdW) heterostructures alternating two-dimensional (2D) materials and surface-confined supramolecular self-assemblies of porous crystals into three-dimensional (3D) stacks. We show that graphene can be transferred on top of a graphite-confined self-assembled 2D porous network, the cavities of which might be filled with functional guests. Subsequent growth of a new 2D host-guest self-assembled monolayer on top of this intermediate vdW heterostructure further extends it into the third dimension. Thus, this versatile approach, potentially not limited in the number of layers, allows creating on demand sequences by the careful choice of the 2D materials and of the presence or not and choice of guest molecules and permits to envisage innovative structures such as record-density bulk heterojunctions.

Nature Physics, Published online: 15 July 2019; doi:10.1038/s41567-019-0570-0

Disorder present in monolayer NbSe2 is found to be able to enhance its superconductivity. A systematic study reveals the origin—disorder-induced multifractality of the electron wavefunctions strengthens the local interactions.

The recent observation of ferromagnetic order in two-dimensional (2D) materials has initiated a booming interest in the subject of 2D magnetism. In contrast to bulk materials, 2D materials can only exhibit magnetic order in the presence of magnetic anisotropy. In the present work we have used the computational 2D materials database (C2DB) to search for new ferromagnetic 2D materials using the spinwave gap as a simple descriptor that accounts for the role of magnetic anisotropy. In addition to known compounds we find 17 novel insulating materials that exhibit magnetic order at finite temperatures. For these we evaluate the critical temperatures from classical Monte Carlo simulations of a Heisenberg model with exchange and anisotropy parameters obtained from first principles. Starting from 150 stable ferromagnetic 2D materials we find ten candidates that are predicted to have critical temperatures exceeding that of CrI 3 . We also study the effect of Hubbard corrections i...

Two-dimensional (2D) nanomaterials are an emerging platform with unique structural and physiochemical properties attracted intense interest in developing high-performance gas and liquid separation membranes. This review provides an overview on the latest breakthrough studies in the fabrication of 2D nanomaterials membranes including atomically thin membranes, laminar and mixed matrix membranes. Especially, we focus on structural features, permeation mechanism as well as gas and liquid separation performance of 2D nanomaterials membranes. Additionally, we highlighted the unique role of 2D nanomaterials in mitigating plasticization and physical aging phenomena in polymer-based membranes. Finally, we underline current challenges and future prospects of this intriguing materials platform for developing next generation of membranes. Highlights • Physiochemical properties and synthesis approaches of various 2D nanomaterials are highlighted • Latest breakt...

Nature Nanotechnology, Published online: 22 July 2019; doi:10.1038/s41565-019-0504-0

In a ferromagnetic layer, an electric current parallel to the magnetization generates opposite spin–orbit torques on the two surfaces of the magnetic film, which is attributed to the generation of spin currents with a spin polarization transverse to the magnetization within the ferromagnet.

Nature Nanotechnology, Published online: 22 July 2019; doi:10.1038/s41565-019-0492-0

The integration of a TMDC monolayer into a high-Q microcavity enables the observation of optical valley Hall effect.

Controlled oxygen plasma exposure of multilayer WSe 2 can modulate the carrier type of WSe 2 field effect transistors. XPS shows with increased exposure, the top WSe 2 layer(s) oxidizes to amorphous WO ( x −3) layer-by-layer with a high degree of controllability as both single or 2 layers can be transformed. A systematic study of Raman and photoluminescence signatures clearly demonstrate the processing times necessary to selectively oxidized the top 1 or 2 layers of exfoliated WSe 2 flakes. WSe 2 devices exposed in the channel regions experience an increase in p-type conduction and large layer-dependent n-type suppression. Devices exposed in the contact region prior to metalization show slight increases of both p-type and n-type conduction. Devices made on flakes, which were completely exposed show suppression of p-type conduction and layer dependent suppression of n-type conduction. Based on these results we were ...

This work addresses the trade‐off between structural and functional responses in three‐dimensional (3D) printable multifunctional materials. The piezoelectric nanocomposite approaches the upper bound of the functional and structural performance via establishing covalent linkages between inclusion and matrix phases. Through high‐resolution 3D printing, this work enables printing highly sensitive freeform transducers and wireless, self‐powered smart wearables with complex microscale architectures.

Abstract

The trade‐off between processability and functional responses presents significant challenges for incorporating piezoelectric materials as potential 3D printable feedstock. Structural compliance and electromechanical coupling sensitivity have been tightly coupled: high piezoelectric responsiveness comes at the cost of low compliance. Here, the formulation and design strategy are presented for a class of a 3D printable, wearable piezoelectric nanocomposite that approaches the upper bound of piezoelectric charge constants while maintaining high compliance. An effective electromechanical interphase model is introduced to elucidate the effects of interfacial functionalization between the highly concentrated perovskite nanoparticulate inclusions (exceeding 74 wt%) and light‐sensitive monomer matrix, shedding light on the significant enhancement of piezoelectric coefficients. It is shown that, through theoretical calculation and experimental validations, maximizing the functionalization level approaches the theoretical upper bound of the piezoelectric constant d ₃₃ at any given loading concentration. Based on these findings, their applicability is demonstrated by designing and 3D printing piezoelectric materials that simultaneously achieve high electromechanical sensitivity and structural functionality, as highly sensitive wearables that detect low pressure air (<50 Pa) coming from different directions, as well as wireless, self‐sensing sporting gloves for simultaneous impact absorption and punching force mapping.

The phosphorization reactions with adjustable components ensure effective and tunable P‐doping (3.83–4.84 at%) with controllable chemical composition into V₂CT_x MXene, via varying reaction temperatures (300–500 °C). Most importantly, P3‐V₂CT_x which has mainly PC bonds, exhibits the smallest overpotential of −163 mV (onset, 28 mV) and a lower Tafel slope of 74 mV dec⁻¹ for the hydrogen evolution reaction.

Abstract

The insufficient strategies to improve electronic transport, the poor intrinsic chemical activities, and limited active site densities are all factors inhibiting MXenes from their electrocatalytic applications in terms of hydrogen production. Herein, these limitations are overcome by tunable interfacial chemical doping with a nonmetallic electron donor, i.e., phosphorization through simple heat‐treatment with triphenyl phosphine (TPP) as a phosphorous source in 2D vanadium carbide MXene. Through this process, substitution, and/or doping of phosphorous occurs at the basal plane with controllable chemical compositions (3.83–4.84 at%). Density functional theory (DFT) calculations demonstrate that the PC bonding shows the lowest surface formation energy (ΔG _Surf) of 0.027 eV Å⁻² and Gibbs free energy (ΔG _H) of –0.02 eV, whereas others such as P‐oxide and PV (phosphide) show highly positive ΔG _H. The P3–V₂CT_x treated at 500 °C shows the highest concentration of PC bonds, and exhibits the lowest onset overpotential of –28 mV, Tafel slope of 74 mV dec⁻¹, and the smallest overpotential of ‐163 mV at 10 mA cm⁻² in 0.5 m H₂SO₄. The first strategy for electrocatalytically accelerating hydrogen evolution activity of V₂CT_x MXene by simple interfacial doping will open the possibility of manipulating the catalytic performance of various MXenes.

In article number https://doi.org/10.1002/adfm.2019012401901240, Tianfeng Chen and co‐workers design bioinspired 2D MoSe₂ nanosheets with high photothermal conversion efficiency to achieve efficient photothermal‐triggered cancer immunotherapy, by activating cytotoxic T lymphocytes, reprogramming tumor associated macrophages to a tumoricidal M1 phenotype, and inactivation of the PD‐1/PD‐L1 pathway to avoid immunologic escape.

By coupling two‐dimensional (2D) titanium oxide and carbide sheets at the molecular level, a self‐standing battery electrode with ideal mechanical durability, excellent high‐current performance, and good cycling stability is achieved. Correspondingly, a full flexible battery showing competitive power density while maintaining a satisfactory energy density, even under mechanical deformations, is devised, which demonstrates great potential for use in wearable powered systems.

Abstract

High‐performance, flexible, and lightweight powering electrodes are urgently needed to meet the increasing interest in deformable electronic devices, particularly those utilizing solid‐state electrolytes and performing at high charging rates, which unfortunately have remained a formidable challenge. Here, by regularly stacking two‐dimensional (2D) titanium oxide and carbide sheets, in which the two kinds of sheets are coupled at the molecular level, a self‐standing electrode is achieved with ideal mechanical durability and excellent electrochemical performance, including superb rate performance (delivering a capacity of 114 mAh g⁻¹ in 3.4 min) and good cycling stability (remaining >93% after 1000 cycles at 1000 mA g⁻¹). Profiting from these advantages, a flexible and safe full lithium‐ion battery, employing a poly(ethylene glycol) diamine‐based gel polymer as the electrolyte, possesses an excellent power density of 1412 W kg⁻¹ while maintaining a high energy density of 59 Wh kg⁻¹, which outperforms most documented flexible batteries that utilize liquid electrolytes and is even comparable with some cells using coin configurations. Importantly, the performance was well maintained under mechanical deformation and after multiple breaking and self‐healing cycles, demonstrating the feasibility for practical application in wearable powering devices. The results highlight the numerous possibilities for utilizing sheet materials to fabricate wearable electrode materials.

Modeling diffusion processes is a significant aspect of developing functional materials, e.g. ion conductors for energy applications. Commonly, modeling diffusion is done by computational science methodologies such as density functional theory and molecular dynamics. Modern approaches are taking advantage of artificial intelligence methods to accelerate research and to find heuristic models.

Abstract

Diffusion describes the stochastic motion of particles and is often a key factor in determining the functionality of materials. Modeling diffusion of atoms can be very challenging for heterogeneous systems with high energy barriers. In this report, popular computational methodologies are covered to study diffusion mechanisms that are widely used in the community and both their strengths and weaknesses are presented. In static approaches, such as electronic structure theory, diffusion mechanisms are usually analyzed within the nudged elastic band (NEB) framework on the ground electronic surface usually obtained from a density functional theory (DFT) calculation. Another common approach to study diffusion mechanisms is based on molecular dynamics (MD) where the equations of motion are solved for every time step for all the atoms in the system. Unfortunately, both the static and dynamic approaches have inherent limitations that restrict the classes of diffusive systems that can be efficiently treated. Such limitations could be remedied by exploiting recent advances in artificial intelligence and machine learning techniques. Here, the most promising approaches in this emerging field for modeling diffusion are reported. It is believed that these knowledge‐intensive methods have a bright future ahead for the study of diffusion mechanisms in advanced functional materials.

A single‐crystalline gallium nitride (GaN) film with atomic‐step terraces is realized on a complementary metal‐oxide‐semiconductor‐compatible Si(100) substrate by using a one‐atom‐thick single‐crystalline graphene buffer layer. The monolayer single‐crystalline graphene provides an in‐plane driving force for the uniform alignment of nitrides domains. This approach can also enable the growth of wafer‐scale hexagonal single‐crystalline films on amorphous or flexible substrates.

Abstract

Fabricating single‐crystalline gallium nitride (GaN)‐based devices on a Si(100) substrate, which is compatible with the mainstream complementary metal‐oxide‐semiconductor circuits, is a prerequisite for next‐generation high‐performance electronics and optoelectronics. However, the direct epitaxy of single‐crystalline GaN on a Si(100) substrate remains challenging due to the asymmetric surface domains of Si(100), which can lead to polycrystalline GaN with a two‐domain structure. Here, by utilizing single‐crystalline graphene as a buffer layer, the epitaxy of a single‐crystalline GaN film on a Si(100) substrate is demonstrated. The in situ treatment of graphene with NH₃ can generate sp³ CN bonds, which then triggers the nucleation of nitrides. The one‐atom‐thick single‐crystalline graphene provides an in‐plane driving force to align all GaN domains to form a single crystal. The nucleation mechanisms and domain evolutions are further clarified by surface science exploration and first‐principle calculations. This work lays the foundation for the integration of GaN‐based devices into Si‐based integrated circuits and also broadens the choice for the epitaxy of nitrides on unconventional amorphous or flexible substrates.

All‐solid‐state flexible asymmetric supercapacitors with the graphene nanoribbon/Co_0.85Se composites as the positive electrode, the graphene nanoribbon/Bi₂Se₃ composites as the negative electrode, and the polymer‐grafted‐graphene oxide membranes as solid‐state electrolytes exhibit an operating voltage of 1.6 V, an energy density of 30.9 Wh kg⁻¹ at the power density of 559 W kg⁻¹, and excellent cycling stability with 89% capacitance retention after 5000 cycles.

Abstract

All‐solid‐state flexible asymmetric supercapacitors (ASCs) are developed by utilization of graphene nanoribbon (GNR)/Co_0.85Se composites as the positive electrode, GNR/Bi₂Se₃ composites as the negative electrode, and polymer‐grafted‐graphene oxide membranes as solid‐state electrolytes. Both GNR/Co_0.85Se and GNR/Bi₂Se₃ composite electrodes are developed by a facile one‐step hydrothermal growth method from graphene oxide nanoribbons as the nucleation framework. The GNR/Co_0.85Se composite electrode exhibits a specific capacity of 76.4 mAh g⁻¹ at a current density of 1 A g⁻¹ and the GNR/Bi₂Se₃ composite electrode exhibits a specific capacity of 100.2 mAh g⁻¹ at a current density of 0.5 A g⁻¹. Moreover, the stretchable membrane solid‐state electrolytes exhibit superior ionic conductivity of 108.7 mS cm⁻¹. As a result, the flexible ASCs demonstrate an operating voltage of 1.6 V, an energy density of 30.9 Wh kg⁻¹ at the power density of 559 W kg⁻¹, and excellent cycling stability with 89% capacitance retention after 5000 cycles. All these results demonstrate that this study provides a simple, scalable, and efficient approach to fabricate high performance flexible all‐solid‐state ASCs for energy storage.

A nickel‐based 2D metal–organic nanosheet is reported using polyvinylpyrrolidone as the structure‐directing agent. The heterobilayers of Ni₇S₆/graphene are derived from the 2D metal–organic framework using thiourea under hydrothermal conditions. The composite is used for electrochemical lithium storage application.

Abstract

Herein, a novel polymer‐templated strategy is described to obtain 2D nickel‐based MOF nanosheets using Ni(OH)₂, squaric acid, and polyvinylpyrrolidone (PVP), where PVP has a dual role as a structure‐directing agent, as well as preventing agglomeration of the MOF nanosheets. Furthermore, a scalable method is developed to transform the 2D MOF sheets to Ni₇S₆/graphene nanosheet (GNS) heterobilayers by in situ sulfidation using thiourea as a sulfur source. The Ni₇S₆/GNS composite shows an excellent reversible capacity of 1010 mAh g⁻¹ at 0.12 A g⁻¹ with a Coulombic efficiency of 98% capacity retention. The electrochemical performance of the Ni₇S₆/GNS composite is superior not only to nickel sulfide/graphene‐based composites but also to other metal disulfide–based composite electrodes. Moreover, the Ni₇S₆/GNS anode exhibits excellent cycle stability (≈95% capacity retention after 2000 cycles). This outstanding electrochemical performance can be attributed to the synergistic effects of Ni₇S₆ and GNS, where GNS serves as a conducting matrix to support Ni₇S₆ nanosheets while Ni₇S₆ prevents restacking of GNS. This work opens up new opportunities in the design of novel functional heterostructures by hybridizing 2D MOF nanosheets with other 2D nanomaterials for electrochemical energy storage/conversion applications.

In this work, stacking defects in hexagonal Ge₄Se₃Te, GaSe, and Sb₂Te₃ are characterized experimentally, followed by an investigation of the influence of observed and hypothetical stacking defects on optical and electronic properties by theoretical means. A connection between observed defects and the bonding situation is then drawn and related to the presence of van der Waals and metavalent bonding in chalcogenides.

Abstract

Phase‐change materials for high‐density data storage traditionally exploit the amorphous‐to‐crystalline phase transition. A number of these compounds are organized in blocks, separated by van der Waals‐like gaps. Such layered chalcogenides are attracting interest due to their unique material properties and the possibility to change their properties upon local rearrangements at the gap, giving rise to novel applications. To better understand the behavior of layered chalcogenides, the connection between structural defects, physical properties, and the bonding situation is highlighted here using electron microscopy, X‐ray diffraction, and density functional theory. In particular, stacking defects in hexagonal Ge₄Se₃Te, GaSe, and Sb₂Te₃ are characterized experimentally, followed by an investigation of the influence of observed and hypothetical stacking defects on optical and electronic properties by theoretical means. Then, a connection between observed defects and the bonding situation in these materials is drawn and related to the presence of van der Waals and metavalent bonding in chalcogenides. Finally, additional experiments are performed to validate the conclusions for other metavalently bonded layered chalcogenides. Transmission electron microscopy provides a powerful tool for direct detection of defects and, when combined with diffraction experiments and ab initio theory, it facilitates the precise investigation of the bonding mechanisms in layered chalcogenides.

A wearable, low‐temperature tolerant and healable strain sensor is assembled from the MXene nanocomposite organohydrogel via a simple solvent displacement method. It exhibits an outstanding antifreezing property (−40 °C), long‐lasting moisture retention (8 d), superior strain sensitivity (GF = 44.85) and wide sensing range (up to 350% strain) to detect human activities.

Abstract

Conductive hydrogels are attracting tremendous interest in the field of flexible and wearable soft strain sensors because of their great potential in electronic skins, and personalized healthcare monitoring. However, conventional conductive hydrogels using pure water as the dispersion medium will inevitably freeze at subzero temperatures, resulting in the diminishment of their conductivity and mechanical properties; meanwhile, even at room temperature, such hydrogels suffer from the inevitable loss of water due to evaporation, which leads to a poor shelf‐life. Herein, an antifreezing, self‐healing, and conductive MXene nanocomposite organohydrogel (MNOH) is developed by immersing MXene nanocomposite hydrogel (MNH) in ethylene glycol (EG) solution to replace a portion of the water molecules. The MNH is prepared from the incorporation of the conductive MXene nanosheet networks into hydrogel polymer networks. The as‐prepared MNOH exhibits an outstanding antifreezing property (−40 °C), long‐lasting moisture retention (8 d), excellent self‐healing capability, and superior mechanical properties. Furthermore, this MNOH can be assembled as a wearable strain sensor to detect human biologic activities with a relatively broad strain range (up to 350% strain) and a high gauge factor of 44.85 under extremely low temperatures. This work paves the way for potential applications in electronic skins, human−machine interactions, and personalized healthcare monitoring.

All solution‐processed La‐doped barium titanate nanocuboids are synthesized as high‐k nanodielectrics for high performance flexible alternating‐current electroluminescent devices with lower operating voltage as well as higher brightness. In addition, a uniform brightness across the whole panel surface of flexible alternating‐current electroluminescent devices and an excellent device reliability are demonstrated via the use of highly conductive and transparent electrodes with a uniform network of crossaligned silver nanowires.

Abstract

Flexible alternating‐current electroluminescent (ACEL) devices have attracted considerable attention for their ability to produce uniform light emission under bent conditions and have enormous potential for applications in back lighting panels, decorative lighting in automobiles, and panel displays. Nevertheless, flexible ACEL devices generally require a high operating bias, which precludes their implementation in low power devices. Herein, solution‐processed La‐doped barium titanate (BTO:La) nanocuboids (≈150 nm) are presented as high dielectric constant (high‐k) nanodielectrics, which can enhance the dielectric constant of an ACEL device from 2.6 to 21 (at 1 kHz), enabling the fabrication of high‐performance flexible ACEL devices with a lower operating voltage as well as higher brightness (≈57.54 cd m⁻² at 240 V, 1 kHz) than devices using undoped BTO nanodielectrics (≈14.3 cd m⁻² at 240 V, 1 kHz). Furthermore, a uniform brightness across the whole panel surface of the flexible ACEL devices and excellent device reliability are achieved via the use of uniform networks of crossaligned silver nanowires as highly conductive and flexible electrodes. The results offer experimental validation of high‐brightness flexible ACELs using solution‐processed BTO:La nanodielectrics, which constitutes an important milestone toward the implementation of high‐k nanodielectrics in flexible displays.

Ion‐conductive and viscosity‐tunable hexagonal boron nitride (hBN) inks are prepared by liquid‐phase exfoliation of hBN nanosheets using cellulosic polymers as dispersants and stabilizers. The hBN inks are compatible with inkjet printing and blade coating, resulting in hBN films with high ionic conductivity and thermal stability that outperform commercial polymer separators in lithium‐ion batteries.

Abstract

Liquid‐phase exfoliation of layered solids holds promise for the scalable production of 2D nanosheets. When combined with suitable solvents and stabilizing polymers, the rheology of the resulting nanosheet dispersions can be tuned for a variety of additive manufacturing methods. While significant progress is made in the development of electrically conductive nanosheet inks, minimal effort is applied to ion‐conductive nanosheet inks despite their central role in energy storage applications. Here, the formulation of viscosity‐tunable hexagonal boron nitride (hBN) inks compatible with a wide range of printing methods that span the spectrum from low‐viscosity inkjet printing to high‐viscosity blade coating is demonstrated. The inks are prepared by liquid‐phase exfoliation with ethyl cellulose as the polymer dispersant and stabilizer. Thermal annealing of the printed structures volatilizes the polymer, resulting in a porous microstructure and the formation of a nanoscale carbonaceous coating on the hBN nanosheets, which promotes high wettability to battery electrolytes. The final result is a printed hBN nanosheet film that possesses high ionic conductivity, chemical and thermal stability, and electrically insulating character, which are ideal characteristics for printable battery components such as separators. Indeed, lithium‐ion battery cells based on printed hBN separators reveal enhanced electrochemical performance that exceeds commercial polymer separators.