The incommensurate (IC) behaviors of ferroelectrics have been widely investigated in inorganic oxides as an exciting branch for aperiodic materials, whereas it still remains a great challenge to achieve such intriguing effects in organic systems. Here, we present that successive ordering of dynamic dipoles in an organic molecular ferroelectric, N-isopropylbenzylaminium trichloroacetate (1), enables unusual incommensurately modulated structures between its paraelectric phase and ferroelectric phase. In particular, 1 exhibits three distinct IC states coupling with a long-range ordering modulation. That is, the incommensurately modulated lattice is ∼7 times as large as its periodic prototype, and the IC structure is well solved using a (3 + 1)D superspace group with the modulated wavevector q = (0, 0, 0.1589). To the best of our knowledge, 1 is the first organic ferroelectric showing such a long-range ordering IC structural modulation. In addition, structural analyses reveal that slowing down dynamic motions of anionic moieties accounts for its modulation behaviors, which also results in dramatic reorientation of dipolar moments and concrete ferroelectric polarization of 1 (∼0.65 μC/cm2). The combination of unique IC structural modulations and ferroelectricity makes 1 a potential candidate for the assembly of an artificially modulated lattice, which will allow for a deep understanding of the underlying chemistry and physics of aperiodic materials.

Nanoscale metal–organic frameworks (nMOFs) have shown tremendous potential in cancer therapy and biomedical imaging. However, their small dimensions present a significant challenge in structure determination by single-crystal X-ray crystallography. We report here the structural determination of nMOFs by rotation electron diffraction (RED). Two isostructural Zr- and Hf-based nMOFs with linear biphenyldicarboxylate (BPDC) or bipyridinedicarboxylate (BPYDC) linkers are stable under intense electron beams to allow the collection of high-quality RED data, which reveal a MOF structure with M12(μ3-O)8(μ3-OH)8(μ2-OH)6 (M = Zr, Hf) secondary building units (SBUs). The nMOF structures differ significantly from their UiO bulk counterparts with M6(μ3-O)4(μ3-OH)4 SBUs and provide the foundation for clarifying the structures of a series of previously reported nMOFs with significant potential in cancer therapy and biological imaging. Our work clearly demonstrates the power of RED in determining nMOF structures and elucidating the formation mechanism of distinct nMOF morphologies.

Supercapacitors attract great interest because of the increasing and urgent demand for environment-friendly high-power energy sources. Ti3C2, a member of MXene family, is a promising electrode material for supercapacitors owing to its excellent chemical and physical properties. However, the highest gravimetric capacitance of the MXene-based electrodes is still relatively low (245 F g−1) and the key challenge to improve this is to exploit more pseudocapacitance by increasing the active site concentration. Here, a method to significantly improve the gravimetric capacitance of Ti3C2Tx MXenes by cation intercalation and surface modification is reported. After K+ intercalation and terminal groups (OH−/F−) removing , the intercalation pseudocapacitance is three times higher than the pristine MXene, and MXene sheets exhibit a significant enhancement (about 211% of the origin) in the gravimetric capacitance (517 F g−1 at a discharge rate of 1 A g−1). Moreover, the as-prepared electrodes show above 99% retention over 10 000 cycles. This improved electrochemical performance is attributed to the large interlayer voids of Ti3C2 and lowest terminated surface group concentration. This study demonstrates a new strategy applicable to other MXenes (Ti2CTx, Nb2CTx, etc.) in maximizing their potential applications in energy storage.

•Facile water based synthesis of V2O5·nH2O nanosheets.•Operando XRD study to follow up the synthesis of V2O5·nH2O nanosheets.•Simple method to fabricate flexible and free standing electrodes (FSE).•Significant improvement in the accessible capacity for lithium-ion intercalation in FSE.Ultrathin hydrated vanadium pentoxide (V2O5·nH2O) nanosheets are fabricated via a water based exfoliation technique. The exfoliation process involves reflux of the precursor, 1:4 mixture of VO2 and V2O5, in water at 80 °C for 24 h. Operando and ex situ X-ray diffraction (XRD) studies are conducted to follow the structural changes during the exfoliation process. The chemical and thermal analyses suggest that the molecular formula of the nanosheet is H0.2V1.8VV0.2IVO5⋅0.5H2O. The V2O5·nH2O nanosheets are mixed with 10% of multi-walled carbon nanotube (MW-CNT) to form a composite material assigned as (VOx-CNT). Free standing electrodes (FSE) and conventionally casted electrodes (CCE) of VOx-CNT are fabricated and then tested as a positive electrode material for lithium batteries. The FSE shows reversible capacities of 300 and 97 mAhg-1 at current densities of 10 and 200 mAhg-1, respectively. This is better than earlier reports for free-standing electrodes. The CCE delivers discharge capacities of 175 and 93 mAhg-1 at current densities of 10 and 200 mAhg-1, respectively.Ultrathin V2O5·nH2O nanosheets are prepared via a facile one-step water based exfoliation technique. Operando XRD is used to track the structural changes during the exfoliation process. A composite material from the V2O5·nH2O nanosheets and 10% of multi-walled carbon nanotube (MW-CNT) is fabricated and shows a promising capacity and rate capabilities for lithium battery application.Download high-res image (116KB)Download full-size image

AlPO4-5 is the most extensively studied material in exploring the crystallization mechanism of aluminophosphate molecular sieves, and it can be synthesized using 4-dimethylaminopyridine (DMAP) as an organic structure-directing agent (OSDA). Achieving the AlPO4-5 intermediate in the crystalline form would be of great importance and significance for this purpose. In this study, we proposed a concept that by carefully regulating the synthesis conditions, crystalline alumimophosphate intermediates could be rationally prepared. A crystalline AlPO4-5 intermediate, (C7H11N2)2(H3O)(Al3P4O16)·(H2O)2.5 (1), was, therefore, synthesized by significantly increasing the amounts of orthophosphoric acid and DMAP. The intermediate 1 consists of alternating organic DMAP and inorganic [Al3P4O16]3− layers with abundant hydrogen bonds and can transform to the AlPO4-5 framework upon heating in air or through a steam-assisted conversion (SAC) method. To unravel the role of DMAP in the transformation, pure AlPO4-5 (2) was also synthesized by altering the synthesis conditions. The supramolecular assembly templating (SAT) effects of DMAP in 1 and 2 were verified via fluorescence spectra. Thus, the π–π stacking interactions between the DMAP molecules and the abundant hydrogen bonds between the adjacent layers are considered to be important for the phase transformation of 1. This crystalline intermediate would promote the understanding of the crystallization mechanism in the system of aluminophosphate molecular sieves.

A novel multilamellar titanosilicate composed of MWW-type nanosheets, Ti-ECNU-7P layered precursor, was directly synthesized for the first time with the assistance of boron atoms as the crystallization-supporting agent and a simple surfactant cetyltrimethylammonium bromide (CTAB) as the interlayer swelling and pillaring agent. The new Ti-ECNU-7P materials were hydrothermally synthesized readily in a wide Si/Ti molar ratio range of 10–200, when the Si/B molar ratio was 10. Ti-ECNU-7P possessed a multilamellar mesostructure, which was constructed via alternate stacking of 2.5 nm MWW zeolite nanosheets and ca. 2.4 nm CTAB molecules. This lamellar titanosilicate possessed large interlayer spacing hardly achieved by conventional hydrothermal synthesis. Subsequent acid treatment and calcination on the multilamellar precursor effectively removed the extraframework Ti species, the organic species intercalated and the majority of framework boron atoms, leading to a hierarchical titanosilicate Ti-ECNU-7 catalyst with relatively high external surface area and high concentration of Ti species on the crystal surface. The catalytic performance of hierarchical Ti-ECNU-7 nanosheets was comprehensively investigated and compared with that of typical titanosilicates in the epoxidation of various bulky alkenes with different oxidants, including aqueous H2O2, tert-butyl hydroperoxide and cumene hydroperoxide. Owing to the hierarchical architecture and more accessible active sites on the external surface, the hierarchical Ti-ECNU-7 catalyst proved to be more active than conventional titanosilicates for selective oxidations involving either bulky substrates or oxidants. Additionally, it was robust against Ti leaching and irreversible deactivation.

High quality zeolite A was synthesized through a hydrothermal process using alkaline-assisted pre-activated halloysite mineral as the alumina and silica source. The synthesis conditions employed in this study were finely tuned by varying the activating temperature, sodium hydroxide content, water content and Si/Al ratio. The obtained zeolite A showed excellent adsorption properties for both single metal cation solutions and mixed cation solutions when the concentrations of the mixed cations were comparable with those in polluted natural river water and industrial wastewater. High adsorptive capacities for Ag+ (123.05 mg/g) and Pb2 + (227.70 mg/g) were achieved using the synthesized zeolite A. This observation indicates that the zeolite A synthesized from alkaline-assisted pre-activated halloysite can be used as a low-cost and relatively effective adsorbent to purify heavy metal cation polluted natural river water and industrial wastewater.Download high-res image (158KB)Download full-size image

The water-triggered reversible transformation plays a significant role in bio-systems. To develop artificial materials with reversible structural transformability under mild conditions would be helpful to understand how bio-systems work. Here we report on a flexible coordination polymer, Cu–(Gly–Thr)·2H2O, whose structure can be controlled by humidity or temperature. This porous coordination polymer shows reversible single-crystal to single-crystal transformation with surprisingly high thermal stability. It was found that the ordered transformation occurs via coordination bonds breaking and reforming without changing the coordination numbers and valence of the copper ion. This reversible transformation makes it especially efficient at taking up CO2 under wet conditions, which is similar to the function of plant stomata.

A novel quasi-zeolite PKU-15, with a rare 3-dimensional structure containing interconnected large (12-ring), medium (10-ring) and small (7-ring) multi-pore channels, was hydrothermally synthesised and characterised. A unique tri-bridging O2− anion is found to be encapsulated in the cage-like (Ge,Si)12O31 building unit and energetically stabilises the PKU-15 framework. The removal of this oxygen atom would convert PKU-15 into a hypothetical zeolite PKU-15H. Thus, PKU-15 can be considered as a unique ‘quasi-zeolite’, which bridges porous germanates and zeolites. Owing to the absence of terminal Ge–OH groups in its structure, PKU-15 shows a remarkably high thermal stability of up to 600 °C. PKU-15 is also the first microporous germanate that exhibits permanent porosity, with a BET area of 428 m2 g−1 and a good adsorption affinity toward CO2.

Two novel 2D covalent organic frameworks (TPT-COF-1 and TPT-COF-2) were synthesized from the flexible 2,4,6-triaryloxy-1,3,5-triazine building blocks on a gram scale, which show high crystallinity and large surface area. The controllable formation of highly ordered frameworks is mainly attributed to the self-assembly Piedfort unit of 2,4,6-triaryloxy-1,3,5-triazine.

A novel two-dimensional dysprosium(III) complex, [Dy(L)(CH3COO)]·0.5DMF·H2O·2CH3OH (1), has been successfully synthesized from a new pyridine-N-oxide (PNO)-containing ligand, namely, N′-(2-hydroxy-3-methoxybenzylidene)pyridine-N-oxidecarbohydrazide (H2L). Single-crystal X-ray diffraction studies reveal that complex 1 is composed of a dinuclear dysprosium subunit, which is further extended by the PNO part of the ligand to form a two-dimensional layer. Magnetic studies indicate that complex 1 shows well-defined temperature- and frequency-dependent signals under a zero direct-current (dc) field, typical of slow magnetic relaxation with an effective energy barrier Ueff of 33.6 K under a zero dc field. Interestingly, powder X-ray diffraction and thermogravimetric analysis reveal that compound 1 undergoes a reversible phase transition that is induced by the desorption and absorption of methanol and water molecules. Moreover, the desolvated sample [Dy(L)(CH3COO)]·0.5DMF (1a) also exhibits slow magnetic relaxation but with a higher anisotropic barrier of 42.0 K, indicating the tuning effect of solvent molecules on slow magnetic relaxation.

Various dimensional frameworks, CMF-1 to CMF-3, were synthesized by using catalytically active [Mo7O24]6− clusters and Cu tetrahedra. After thorough studies, the relationships between synthesis conditions and products were obtained and shown in composition diagrams. Besides, CMF-1 to CMF-3 all showed excellent catalytic activities in the degradation of methylene blue.

A novel microporous aluminoborate, denoted as PKU-3, was prepared by the boric acid flux method. The structure of PKU-3 was determined by combining the rotation electron diffraction and synchrotron powder X-ray diffraction data with well resolved ordered Cl– ions in the channel. Composition and crystal structure analysis showed that there are both proton and chlorine ions in the channels. Part of these protons and chlorine ions can be washed away by basic solutions to activate the open pores. The washed PKU-3 can be used as an efficient catalyst in the Strecker reaction with yields higher than 90%.

Pb- or Bi-based perovskite oxides have been widely studied and used because of their large ferroelectric polarization features induced by stereochemically active 6s2 lone pair electrons. It is intriguing whether this effect could exist in other related systems. Herein, we designed and synthesized a mixed Pb and Bi A site polar compound, PbBiNb5O15, with the TTB framework. The as-synthesized material turns out to be a relaxor with weak macroscopic ferroelectricity but adopts strong local polarizations. What’s more, unusual five orders of incommensurate satellite reflections with strong intensities were observed under the electron diffraction, suggesting that the modulation is highly developed with large amplitudes. The structural modulation was solved with a (3 + 1)D superspace group using high-resolution synchrotron radiation combined with anomalous dispersion X-ray diffraction technique to distinguish Pb from Bi. We show that the strong modulation mainly originates from lone-pair driven Pb2+–Bi3+ ordering in the large pentagonal caves, which can suppress the local polarization in x–y plane in long ranges. Moreover, the as-synthesized ceramics display strong relaxor ferroelectric feature with transition temperature near room temperature and moderate dielectric properties, which could be functionalized to be electromechanical device materials.

We present a novel luminescent metal–organic framework (LMOF) based on zirconium metal oxide cluster Zr6O8 bonding with a new tetratopic linker 1,3,6,8-tetrakis(4′-carboxy[1,1′-biphenyl]-4-yl-)pyrene. This (4,12)-connected ftw-a-type net is composed of a large solvent-accessible volume of 79.5% volume per unit cell with a BET surface area up to 3540.5 m2 g−1. The activated LMOF exhibits an unprecedented fluorescence quenching effect triggered by nitrobenzene (NB) with quench percentage up to 99.5%, and could reversibly take up 14.7 mmol g−1 of NB under atmospheric conditions. The breakthrough curve of CH4 and C2H6 at 298 K and 2.0 MPa demonstrates that the activated LMOF has high-performance selective adsorption for CH4 with a selectivity of 25.45, which is an unusually high value as compared with those of reported materials.

An emerging strategy for exploring the application of polyoxometalates (POMs) is to assemble POM clusters into open-framework materials, especially inorganic–organic hybrid three-dimensional (3D) open-framework materials, via the introduction of different organic linkers between the POM clusters. This strategy has yielded a few 3D crystalline POMs of which a typical class is the group of polyoxometalate metal–organic frameworks (POMMOFs). However, for reported POMMOFs, only coordination bonds are involved between the linkers and POM clusters, and it has not yet produced any covalently bonded polyoxometalate frameworks. Here, the concept of “covalently bonded POMs (CPOMs)” is developed. By using vanadoborates as an example, we showed that the 3D CPOMs can be obtained by a condensation reaction through the oxolation mechanism of polymer chemistry. In particular, suitable single crystals were harvested and characterized by single-crystal X-ray diffraction. This work forges a link among polymer science, POM chemistry, and open-framework materials by demonstrating that it is possible to use covalent bonds according to polymer chemistry principles to construct crystalline 3D open-framework POM materials.

Two new 2D COFs were synthesized from triformylcyclotrianisylene, which show not only thermal stability but also hydrolytic stability. CTV-COF-1 with smaller pore size stored a high hydrogen level of 1.3 wt% at low pressure, while CTV-COF-2 with larger pore size showed superior carbon dioxide uptake, up to 250 cm3 g−1 at 298 K and 50 bar.

A new alkali-metal borogermanate with noncentrosymmetric structure, namely, Cs2GeB4O9, has been discovered, and a large crystal with dimensions of 20 × 16 × 8 mm3 has been grown by a high-temperature top-seeded solution method using Cs2O–B2O3 as a flux. The compound crystallizes in the tetragonal space group I4̅ with a = b = 6.8063(2) Å, c = 9.9523(7) Å, V = 461.05(4) Å3, and Z = 2. It features a three-dimensional anionic open framework based on GeO4 tetrahedra and B4O9 clusters that are interconnected via corner-sharing, forming one-dimensional channels of nine-/ten-membered rings along the a and b axes, which are occupied by Cs+ cations. Cs2GeB4O9 exhibits a very high thermal stability with a melting point of 849 °C, and it possesses a short-wavelength absorption edge onset at 198 nm determined by UV–vis transmission spectroscopy measurements on a slab of polished crystal. Powder second-harmonic generation (SHG) measurement on sieved crystals reveals that Cs2GeB4O9 is a type I phase-matchable material with a strong SHG response of about 2.8 × KH2PO4. The preliminary investigation indicates that Cs2GeB4O9 is a new promising second-order nonlinear-optical crystalline material.

A new open-framework germanate, denoted as GeO-JU90, was prepared by the hydrothermal synthesis method using 1,5-bis(methylpyrrolidinium)pentane dihydroxide as the organic structure-directing agent (SDA). The structure of GeO-JU90 was determined from synchrotron X-ray powder diffraction (XRPD) data using the charge-flipping algorithm. It revealed a complicated framework structure containing 11 Ge atoms in the asymmetric unit. The framework is built of 7-connected Ge7 clusters and additional tetrahedral GeO3(OH) units forming a new three-dimensional interrupted framework with interesting 12 × 12 × 11-ring intersecting channels. The Ge K-edge extended X-ray absorption fine structure (EXAFS) analysis was performed to provide the local structural information around Ge atoms, giving rise to a first-shell contribution from about 4.2(2) O atoms at the average distance of 1.750(8) Å. The guest species in the channels were subsequently determined by the simulated annealing method from XRPD data combining with other characterization techniques, e.g., 13C NMR spectroscopy, infrared spectroscopy (FTIR), compositional analyses, and thermogravimetric analysis (TGA). Crystallographic data |(C15N2H32)(NH4)|[Ge11O21.5(OH)4], orthorhombic Ama2 (No. 40), a = 37.82959 Å, b = 15.24373 Å, c = 12.83659 Å, and Z = 8.

In a nonprotic solvent, a (H2O)2(COOH)3(L) supramolecular synthon was found to guide the formation of five new crystal structures together with HPB-3a (1,3,5-tris(4-carboxyphenyl)-2,4,6-tris(4-tert-butylphenyl)benzene). This synthon acted as a 3-connected trigonal planar node (L = acetone) in 1 [(HPB-3a)(H2O)2(acetone)3] or a 4-connected trigonal pyramidal node (L = pyridyl) in 2 [(HPB-3a)(bipy)0.5(H2O)2], 3 [(HPB-3a)(azopy)0.5(H2O)2], 4 [(HPB-3a)(bipy-ete)0.5(H2O)2], and 5 [(HPB-3a)(bipy-eta)0.5(H2O)2] (bipy = 4,4′-bipyridine, azopy = azopyridine, bipy-ete = trans-1,2-bis(4-pyridyl)ethene, bipy-eta = 1,2-bis(4-pyridyl)ethane). The formation of this synthon could be attributed to the C3-symmetry of planar HPB-3a molecules and the hydrophobic interactions between tert-butyl groups. 1 represents a continuously interdigitated 63-hcb layer structure. 2–5 are with the same topology and display amazing 2D homochiral bilayers, which were penetrated in parallel by two others (“above” and “below”) with the opposite chirality to form overall 3D racemic networks. However, the synthon was not as robust in the presence of protic solvents. In 6 [(HPB-3a)(MeOH)3], carboxyl groups interact directly with hydroxyl groups of methanol to form 1D hydrogen bonding chains. The structure is a 3-fold interpenetrated 49·66-acs network.

A novel multilamellar titanosilicate composed of MWW-type nanosheets, Ti-ECNU-7P layered precursor, was directly synthesized for the first time with the assistance of boron atoms as the crystallization-supporting agent and a simple surfactant cetyltrimethylammonium bromide (CTAB) as the interlayer swelling and pillaring agent. The new Ti-ECNU-7P materials were hydrothermally synthesized readily in a wide Si/Ti molar ratio range of 10–200, when the Si/B molar ratio was 10. Ti-ECNU-7P possessed a multilamellar mesostructure, which was constructed via alternate stacking of 2.5 nm MWW zeolite nanosheets and ca. 2.4 nm CTAB molecules. This lamellar titanosilicate possessed large interlayer spacing hardly achieved by conventional hydrothermal synthesis. Subsequent acid treatment and calcination on the multilamellar precursor effectively removed the extraframework Ti species, the organic species intercalated and the majority of framework boron atoms, leading to a hierarchical titanosilicate Ti-ECNU-7 catalyst with relatively high external surface area and high concentration of Ti species on the crystal surface. The catalytic performance of hierarchical Ti-ECNU-7 nanosheets was comprehensively investigated and compared with that of typical titanosilicates in the epoxidation of various bulky alkenes with different oxidants, including aqueous H2O2, tert-butyl hydroperoxide and cumene hydroperoxide. Owing to the hierarchical architecture and more accessible active sites on the external surface, the hierarchical Ti-ECNU-7 catalyst proved to be more active than conventional titanosilicates for selective oxidations involving either bulky substrates or oxidants. Additionally, it was robust against Ti leaching and irreversible deactivation.

Two novel 2D covalent organic frameworks (TPT-COF-1 and TPT-COF-2) were synthesized from the flexible 2,4,6-triaryloxy-1,3,5-triazine building blocks on a gram scale, which show high crystallinity and large surface area. The controllable formation of highly ordered frameworks is mainly attributed to the self-assembly Piedfort unit of 2,4,6-triaryloxy-1,3,5-triazine.

A novel quasi-zeolite PKU-15, with a rare 3-dimensional structure containing interconnected large (12-ring), medium (10-ring) and small (7-ring) multi-pore channels, was hydrothermally synthesised and characterised. A unique tri-bridging O2− anion is found to be encapsulated in the cage-like (Ge,Si)12O31 building unit and energetically stabilises the PKU-15 framework. The removal of this oxygen atom would convert PKU-15 into a hypothetical zeolite PKU-15H. Thus, PKU-15 can be considered as a unique ‘quasi-zeolite’, which bridges porous germanates and zeolites. Owing to the absence of terminal Ge–OH groups in its structure, PKU-15 shows a remarkably high thermal stability of up to 600 °C. PKU-15 is also the first microporous germanate that exhibits permanent porosity, with a BET area of 428 m2 g−1 and a good adsorption affinity toward CO2.

We present a novel luminescent metal–organic framework (LMOF) based on zirconium metal oxide cluster Zr6O8 bonding with a new tetratopic linker 1,3,6,8-tetrakis(4′-carboxy[1,1′-biphenyl]-4-yl-)pyrene. This (4,12)-connected ftw-a-type net is composed of a large solvent-accessible volume of 79.5% volume per unit cell with a BET surface area up to 3540.5 m2 g−1. The activated LMOF exhibits an unprecedented fluorescence quenching effect triggered by nitrobenzene (NB) with quench percentage up to 99.5%, and could reversibly take up 14.7 mmol g−1 of NB under atmospheric conditions. The breakthrough curve of CH4 and C2H6 at 298 K and 2.0 MPa demonstrates that the activated LMOF has high-performance selective adsorption for CH4 with a selectivity of 25.45, which is an unusually high value as compared with those of reported materials.

Two new 2D COFs were synthesized from triformylcyclotrianisylene, which show not only thermal stability but also hydrolytic stability. CTV-COF-1 with smaller pore size stored a high hydrogen level of 1.3 wt% at low pressure, while CTV-COF-2 with larger pore size showed superior carbon dioxide uptake, up to 250 cm3 g−1 at 298 K and 50 bar.

We apply for the first time transmission electron microscopy to the direct observation of the deep-UV nonlinear optical crystal KBe2BO3F2 (KBBF) grown using different methods. Two kinds of electron diffraction patterns were observed in the hydrothermally synthesized KBBF along the [120] direction, which resulted from the coexistence of two structures with space groups R32 and Rc. As a comparison, the flux grown KBBF crystals show uniform R32 structures. Furthermore we observed a twin boundary in flux KBBF which corresponds to the (23)R32 crystallographic plane. Two structure models are proposed here for the twin boundary. These observations on the microstructure and defects were not disclosed in previous powder XRD and optical microscopy experiments and shed new light on the understanding of the structure and defects of KBBF crystals.

The synthesis of two dimensional (2D) materials from transition metal oxides, chalcogenides, and carbides mostly involve multiple exfoliation steps in which hazardous solvents and reagents are used. In this study, hydrated vanadium pentoxide (V2O5·nH2O) nanosheets with a thickness of a few nanometers were prepared via a facile environmentally friendly water based exfoliation technique. The exfoliation process involved refluxing the precursor, vanadium dioxide (VO2(B)), in water for a few days at 60 °C. The proposed exfoliation mechanism is based on the intercalation/insertion of water molecules into the VO2(B) crystals and the subsequent cleavage of the covalent bonds holding the layers of VO2(B) together. The thermal and chemical analyses showed that the approximate chemical composition of the nanosheets is H0.4V2O5·0.55H2O, and the percentage of VV content to that of VIV in the nanosheets is about 80(3)% to 20(3)%. The exfoliated aqueous suspension of the V2O5·0.55H2O nanosheets was successfully deposited onto multi-walled carbon nanotube (MW-CNT) paper to form free-standing electrodes with a thickness of the V2O5·0.55H2O layer ranging between 45 and 4 μm. A series of electrochemical tests were conducted on the electrodes to determine the cyclability and rate capability of lithium insertion into V2O5·0.55H2O nanosheets. The electrodes with the thinnest active material coating (∼4 μm) delivered gravimetric capacities of up to 480 and 280 mA h g−1 when cycled at current densities of 10 and 200 mA g−1, respectively.