Herein, the cytocompatibility of selected MAX phases, Ti3AlC2, Ti3SiC2, and Ti2AlN, were systematically evaluated using in vitro tests for the first time. These phases were anoxic to preosteoblasts and fibroblasts. Compared with the strong viable fibroblasts, the different cellular responses of these materials were clearly distinguishable for the preosteoblasts. Under an osteoblastic environment, Ti2AlN exhibited better cell proliferation and differentiation performance than Ti3AlC2 and Ti3SiC2. Moreover, the performance was superior to that of a commercial Ti–6Al–4V alloy and comparable to that of pure Ti. A possible mechanism was suggested based on the different surface oxidation products, which were determined from the binding energy of adsorbed Ca2+ ions using first-principles calculations. Compared with the partially oxidized TiCxOy layer on Ti3AlC2 and Ti3SiC2, the partially oxidized TiNxOy layer on the Ti2AlN had a stronger affinity to the Ca2+ ions, which indicated the good cytocompatibility of Ti2AlN.Keywords: cytocompatibility; first-principles calculations; in vitro test; MAX phase; Ti2AlN;

We demonstrate fabrication of a two-dimensional Hf-containing MXene, Hf3C2Tz, by selective etching of a layered parent Hf3[Al(Si)]4C6 compound. A substitutional solution of Si on Al sites effectively weakened the interfacial adhesion between Hf–C and Al(Si)–C sublayers within the unit cell of the parent compound, facilitating the subsequent selective etching. The underlying mechanism of the Si-alloying-facilitated etching process is thoroughly studied by first-principles density functional calculations. The result showed that more valence electrons of Si than Al weaken the adhesive energy of the etching interface. The MXenes were determined to be flexible and conductive. Moreover, this 2D Hf-containing MXene material showed reversible volumetric capacities of 1567 and 504 mAh cm–3 for lithium and sodium ions batteries, respectively, at a current density of 200 mAg–1 after 200 cycles. Thus, Hf3C2Tz MXenes with a 2D structure are candidate anode materials for metal-ion intercalation, especially for applications where size matters.Keywords: 2D materials; DFT calculations; electrochemical properties; MXenes; selective etching;

A novel family of Ti3C2Tx/ferrite composites with high reflection loss was developed using a facile in situ co-precipitation method. The as-synthesized Ti3C2Tx/ferrite composite with a 5 wt% Ti3C2Tx MXenes loading exhibited high reflection loss (−42.5 dB) at 13.5 GHz. The effective absorption bandwidth of the 5 wt% Ti3C2Tx/Ni0.5Zn0.5Fe2O4 composite reached ∼3 GHz (12–15 GHz) in the K-band. The incorporation of Ti3C2Tx MXenes improved the electromagnetic impedance of the Ti3C2Tx/Ni0.5Zn0.5Fe2O4 composite resulting from the enhanced electrical conductivity. The potential electromagnetic wave absorption mechanisms were revealed, which may contain magnetic loss, dielectric loss, conductivity loss, multiple reflections, and scattering. The technique is facile, fast, scalable, and favorable for the commercialization of this composite. This study provides a potential way to develop EM wave absorbing materials for a large family of MXenes/ferrite composites.

Copper matrix composites reinforced with carbide-coated graphene nanoplatelets (GNPs) were investigated in order to understand the role of the interlayers on the thermal, electrical, mechanical and electro-tribological properties of the composites. The TiC or VC coatings were formed in situ on the two sides of GNPs through a controllable reaction in molten salts. Compared with bare GNPs composites, the bonding between the GNPs and copper was improved. Accordingly, the tensile strength and the fracture elongation of Cu/GNPs composites with an interlayer were enhanced by strengthened interfacial bonding. Furthermore, the wear resistance of Cu/GNPs composites was remarkably improved.

A liquid hyperbranched polycarbosilane (LHBPCS) with stoichiometric C/Si ratio but without unsaturated groups was synthesized. Different from traditional thermal crosslinking, ultraviolet (UV) irradiation crosslinking was taken. The molecular weight, the consumption of SiH group and ceramic yield of LHBPCS showed an increase trend with increasing the UV irradiation time. After 30 min of UV irradiation, 71.8 wt% ceramic yield was obtained. In addition, extra divinyldimethylsilane was added into LHBPCS. Under UV irradiation, both the SiH group and vinyl group of divinyldimethylsilane were consumed. But the reaction extend of vinyl group was much faster than that of SiH group. Compared with pure LHBPCS, the mixture of LHBPCS and 5 wt% divinyldimethylsilane gave a higher ceramic yield of 79 wt% after 30 min of UV irradiation. By heating the crosslinked LHBPCS to 1000 °C, a near stoichiometric SiC ceramic was got. It exhibited excellent thermal stability at 1400 °C in air.

The in situ generated ternary compound Al3BC shows good dispersion on the surfaces of B4C particles (10 ± 0.6 μm), obtained using the molten-salt method rather than the ball-milling method, which can form a conductive network in the pulse electric current sintering process to improve the sinterability of B4C. The sintering behaviour, microstructure and mechanical properties of compacts were investigated at different sintering temperatures and Al3BC contents. The study found that the relative density, elastic modulus, Vickers hardness, and fracture toughness of samples reached as high as 100%, 495 GPa, 37.0 GPa, and 6.32 MPa m1/2 at 1700 °C, respectively, when the content of Al3BC was 18 wt.%. The crack propagation mode can provide an explanation for the higher toughness than that of pure B4C (3.19 MPa m0.5). Additionally, the good dispersion of Al3BC in B4C was found to change the fracture mode from the single transgranular mode to a mixture of intergranular and transgranular modes. The compositions of the compacts were almost pure B4C.

V2AlC coatings prepared by magnetron sputtering on a Zr substrates were irradiated with He ions to simulate the behavior of accident tolerant fuels (ATFs) in a reactor. TEM analysis and scratch test showed that the He bubbles preferentially nucleated along the substrate-coating interface and resulted in a loss of mechanical resistance of the V2AlC coating (i.e., reduced the adhesion of coating). This study provides a first insight into the irradiation-induced mechanical behavior of V2AlC coating on the Zr substrate and demonstrates the importance of improving the irradiation resistance of the cladding-coating system by optimizing the interfacial structure between the cladding and the coating materials for the development of ATFs.Download high-res image (602KB)Download full-size image

The spark plasma sintering (SPS) method was used to study the mechanism of reaction interface between Zr and Ti3AlC2 with electric current going through it. It was found that electric current greatly reduced the bonding temperature of Zr and Ti3AlC2. By the micro-structure analysis of the interface through SEM/EDS, it was found that Al atoms diffused from the Ti3AlC2 substrate into the Zr side and reacted with Zr to form the Zr-Al compounds at the interface, which is the strengthening mechanism of Ti3AlC2-Zr bonding. The thickness of reaction layers (Zr-Al alloy) was from 0.879 to 13.945 mm depending on different sintering condition. Current direction, heating rate, soaking time, pulse patterns all influenced the diffusion of Al atoms which affected the joining quality of Zr and Ti3AlC2.

Efficient nuclear waste treatment and environmental management are important hurdles that need to be overcome if nuclear energy is to become more widely used. Herein, we demonstrate the first case of using two-dimensional (2D) multilayered V2CTx nanosheets prepared by HF etching of V2AlC to remove actinides from aqueous solutions. The V2CTx material is found to be a highly efficient uranium (U(VI)) sorbent, evidenced by a high uptake capacity of 174 mg g–1, fast sorption kinetics, and desirable selectivity. Fitting of the sorption isotherm indicated that the sorption followed a heterogeneous adsorption model, most probably due to the presence of heterogeneous adsorption sites. Density functional theory calculations, in combination with X-ray absorption fine structure characterizations, suggest that the uranyl ions prefer to coordinate with hydroxyl groups bonded to the V-sites of the nanosheets via forming bidentate inner-sphere complexes.

Carbon fiber reinforced carbon composites (Cf/C) were first joined by combining electric field-assisted sintering technology and using a Ti3SiC2 (TSC) tape film as interlayer. A joint with shear strength of 26.3 ± 1.7 MPa was obtained within 12 min at a joining temperature of 1200 °C. The joint morphology, interface reaction, shear fracture behavior, and joining mechanism were investigated in detail. To achieve reliable joining of a Cf/C composite to itself via a TSC interlayer, the current work show the crucial controlling factor of interface reaction on the shear strength and the shear fracture behavior. Optimized bonding could be achieved without sacrificing the high strength of the carbon fibers and also taking advantage of the pseudo-plasticity feature of the TSC interlayer. A possible high-toughness joining structure was also proposed based on these results. The current-aid joining technique shortened significantly the bonding process of the Cf/C composites at moderate temperatures, and simplifies the manufacture of components with complex shapes.

Copper matrix composites reinforced with graphene nanoplatelets (GNPs) were prepared via molecular-level mixing process and spark plasma sintering process. The impacts of graphene content on microstructure, mechanical performance, thermal diffusivity, electrical conductivity and tribological properties of the composites were investigated. For microstructure, GNPs distributed randomly in composites with low graphene concentration (no more than 0.8 vol.%), but aligned in the direction perpendicular to the consolidation force when graphene concentration was above 2.0 vol.%. The mechanical performance of copper was strengthened evidently by the graphene addition. However, the strengthen effects were firstly enhanced and then deteriorated by increasing graphene content. Thermal diffusivity showed a constant decrease with the increase of graphene content. Anisotropy thermal performance was obtained by composites with graphene alignment. Furthermore, graphene addition showed little negative impact on electrical conductivity but dramatically improved tribological performance.

MXenes, serving as a novel family of two-dimensional (2D) metal carbides, have attracted great research interest as one of the promising electrode materials due to the unique properties. However, to our best knowledge, the 2D titanium carbide (one kind of MXene) used in constructing microsupercapacitors (MSCs) has not yet been reported to date. To this end, we firstly produce the MXene films on various kinds of substrates including polyethylene terephthalate (PET), silicon oxide film and titanium plate through vacuum-filtrating and subsequent controlled transferring. On this basis, flexible all-solid-state symmetric MSCs on PET substrate based on MXene films are fabricated by micro-fabrication process using polyvinyl alcohol (PVA)/H2SO4 as gel electrolyte. The results show that the as-made MSC has an ultrahigh rate performance with the scan rate of up to 1000 V s−1 as well as an ultrafast frequency response (τ0 = 0.5 ms). In addition, the MSC delivers a large volumetric capacitance of 1.44 F cm−3, a high volumetric energy density (0.2 mWh cm−3) at the current density of 0.288 A cm−3 and a good cycling stability. Our research results presented here may pave the way for a new potential application of MXene in micro-power suppliers and micro-energy storage devices.We constructed MXene-based flexible all-solid-state symmetric micro super capacitors on PET substrate through micro-fabrication process, and the microsupercapacitors exhibited an excellent rate performance with the scan rate of up to 1000 V s−1.

•High purity of Ti3AlC2 coatings were fabricated using liquid plasma spraying.•The effects of solution properties on coating microstructures were evaluated.•The deposition mechanism of liquid plasma sprayed Ti3AlC2 coatings was discussed.Ti3AlC2 tends to partially decompose into TiC phase during deposition by traditional thermal spray techniques, preventing their use in surface anti-corrosion applications. Here, Ti3AlC2 coatings were synthesized using liquid plasma spraying (LPS). Although the average temperature of particles measured in LPS was higher than 2200 K, enough to decompose Ti3AlC2 phase, the resulting sprayed Ti3AlC2 particles were intact. This is probably due to formation of a protective oxide on the surface in the high-temperature steam. The phase purity of Ti3AlC2 coating was high when using water as solvent, but low with a solvent of a mixture of water and alcohol. Different pH values of the solutions influence the phase purity of Ti3AlC2 coatings. The alkaline solutions show detrimental effect on the conservation of Ti3AlC2 phase. The mechanism of improved structural integrity of Ti3AlC2 phase at high temperature through LPS was revealed by microstructural and compositional analysis.

MXenes, a novel family of two-dimensional metal carbides, are receiving intense attention for lithium-ion batteries (LIBs) and supercapacitors because they have high volumetric capacitance exceeding all carbon materials. However, serious interlayer stacking exists in MXene particles, which greatly decreases the electrical conductivity in the bulk and hinders the accessibility of interlayers to electrolyte ions. Thus, multi-stacked MXene particles exhibit low capacitance and poor rate capability. Herein, we report an effective strategy to directly improve the electrochemical performance of multi-stacked MXene (Ti3C2Tx) particles as LIB anode materials. It was successfully realized by growing conductive “carbon nanofiber (CNF) bridges” within the gaps of each Ti3C2Tx particle as well as the outside. With the help of these CNFs, the as-prepared Ti3C2/CNF particles exhibited significantly improved reversible capacity compared with pure Ti3C2Tx particles. More remarkably, even at an ultrahigh rate of 100 C, the capacity of Ti3C2/CNF hybrid particles was just slightly lower than that of pure Ti3C2Tx particles at 1 C, and there was no capacity decay after 2900 cycles at 100 C, demonstrating excellent rate capability and superior long-term stability at the ultrahigh rate.

A robust strategy is explored to graft poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) brushes on two-dimensional vanadium carbide (V2C) materials through self-initiated photografting and photopolymerization (SIPGP). CO2 and temperature dual-responsive properties of PDMAEMA allow this hybrid to be used as a smart system for tuning the transmittance and conductivity of V2C.

Since the discovery of graphene, two-dimensional (2D) materials have been receiving increased attention. The quest for new 2D materials with unique structure and special properties has become urgent. Herein we report on the preparation of a new kind of ternary 2D material, Ti4AlN3 nanosheets, by liquid exfoliation of the corresponding laminated MAX phase. The obtained Ti4AlN3 nanosheets, bearing abundant surface groups, can be further used to fabricate micro-patterns via micro-contact printing (μCP) and subsequently functionalized through self-initiated photografting and photopolymerization (SIPGP) to achieve MAX-based hybrid patterned polymer brushes. Our work opens a door to explore the synthesis of 2D hybrid materials for functional applications based on the traditional MAX phases.

Synthesis of B4C–TiB2 composite powders via a carbide boronizing process was performed in a pulsed electric current sintering furnace with a specially designed graphite die/punch set-up. Pure B4C–TiB2 powders could be obtained at 1200 °C for 0 min or 1000 °C for 15 min with a total thermal cycle time of only 12–25 min. In the as-prepared B4C–TiB2 composite powders, submicrometer B4C particles were surrounded by nano-TiB2 particles with an average particle of less than 50 nm. The bulk B4C–TiB2 ceramic sintered from the as-prepared composite powders had a relative density of 96% with ultrafine microstructures.

Porous Ti2AlN ceramic, which was measured to be 3.23 g/cm3 about 74.9% of its theoretical value, was successfully synthesized and simultaneously consolidated from starting raw materials of Ti, Al, and TiN powders with a near-stoichiometric molar ratio of 1:1.03:1 by a microwave sintering method at 1200 °C for 30 min in an argon atmosphere. When sintered at 1200 °C for 1 h, the Ti2AlN grain showed a preferred growth behavior along the c-axis in the final ceramic, as shown by the results of an X-ray diffraction study. The Lotgering orientation factor on the surface of as-sintered Ti2AlN ceramic was as high as f(0 0 ℓ) = 0.598. A traditional synthesis method in a quartz tube furnace was also applied to synthesize the materials under the same conditions, but this did not result in similar preferred grain growth phenomenon. Factors affecting the orientation were discussed, and an underlying growth mechanism was suggested. Also, a dense Ti2AlN sample was obtained by re-sintering the porous Ti2AlN sample using a spark plasma sintering method. As a result, the orientation was maintained, and the density was measured to be 4.21 g/cm3, which reached 97.6% of its theoretical value.

Commercial SiC ceramics were joined by electric field-assisted sintering technology using a Ti3SiC2 (TSC) tape film. A SiC/TSC/SiC joining sample with bend strength of 80.4 MPa was obtained at a low joining temperature of 1300 °C within a total time of 15 min. Three simple failure mechanism models were established, and the failure mechanisms of the joints joined at different temperatures were then revealed. The element diffusion and phase transition behaviour in the joining interface were investigated.

Transparent alumina was fabricated by spark plasma sintering with AlF3 doping at a high heating rate of 100 °C min−1 and a moderate loading pressure of 73 MPa. The sintered AlF3-doped alumina was dark in color due to light absorption by F− substitution and by the resulting defects induced in the alumina lattice. An AlF3 doping concentration of 0.1% was found best for producing transparent alumina. A possible mechanism was proposed to explain the doping effect under the present sintering condition.

•The mechanical strength and degradation rate of CSMPC composites are discussed.•The CSMPC composites exhibited good bioactivity to form bone-like apatite.•The CSMPC composites also show good biocompatibility.A novel calcium sulfate/magnesium phosphate cement (CSMPC) composite was prepared and studied in the present work. The physical properties including the phases, the microstructures, the setting properties and the compressive strengths of the CSMPCs were studied. The bio-performances of the CSMPCs were comprehensively evaluated using in vitro simulated body fluid (SBF) method and in vitro cell culture. The dependence of the physical and chemical properties of the CSMPC on its composition and microstructure was studied in detail. It is found that the CSMPC composites exhibited mediate setting times (6–12 min) compared to the calcium sulfate (CS) and the magnesium phosphate cement (MPC). They showed an encapsulation structure in which the unconverted hexagonal prism CSH particles were embedded in the xerogel-like MPC matrix. The phase compositions and the mechanical properties of the CSMPCs were closely related to the content of MPC and the hardening process. The CSMPCs exhibited excellent bioactivity and good biocompatibility to support the cells to attach and proliferate on the surface. The CSMPC composite has the potential to serve as bone grafts for the bone regeneration.

Carbon nanotube (CNT)–Ni0.5Zn0.5Fe2O4 powders were prepared by in situ chemical precipitation and hydrothermal processing, and further sintered by microwave sintering technology. The results show that CNTs acted as ‘heating source’ and promoted the consolidation of composites during the microwave sintering process. However, too much CNTs (such as 5 wt%) led to phase decomposition and reduction of ferrite materials because of the ultra-high localized temperature building up in the interface of CNTs and ferrite grains. The electrical conductivity of composites increased by more than seven orders of magnitude when compared to that of pure Ni0.5Zn0.5Fe2O4, and remained a high value at the temperature of 70 K (for example, 1 wt% CNT/Ni0.5Zn0.5Fe2O4 sample kept conductivity of 0.1 S/m). The saturation magnetization was strongly dependent on the mass percentage of CNTs. With the increase in CNT content, both the real and the imaginary permittivity were increased in the frequency region 0.6–5 GHz (L and S bands). According to the measured results of ϵrϵr and μrμr, the frequency-dependent reflectance loss (RL) of CNT/Ni0.5Zn0.5Fe2O4 composite ceramics with different CNT content was evaluated. The CNT-doped ferrite ceramics discussed herein is very promising to be used in an on-beam-line high-order mode (HOM) load in particle accelerators based on superconducting RF due to their excellent low-temperature characteristics.

Cr-doped amorphous, γ, θ and α-alumina phosphors are carefully synthesized and comprehensively studied to reveal correlations between crystal structure, doping concentration and photoluminescence property. All phosphors exhibit characteristic phase dependent emission behavior: their luminescence intensity and peak position are found to be closely dependent on crystal structure of alumina phases. Luminescence intensity and critical quenching concentration increase drastically with phase transition sequence of amorphous–γ–θ–α. Crystal field parameters are extracted from UV–Vis spectra and the calculated Dq/B values of all alumina phases are larger than 2.3. An alternative possible emission mechanism for γ and θ alumina is deduced from the emission character.Highlights► Cr-doped polymorph alumina phosphors are carefully synthesized. ► Photoluminescence property of these polymorphs are comprehensively studied. ► Luminescence behavior are found crystal structure dependent. ► Crystal field theory is employed to discuss the luminescence character.

Pure Ca-α-SiAlON:Eu2+ was synthesized by microwave sintering method at a relatively low temperature of 1550°C. Photoluminescence intensity of the resultant phosphor was higher than those of the samples synthesized by conventional gas-pressure sintering technique at 1750°C. When it was excited at 450 nm, the as-prepared yellow Ca-α-SiAlON:Eu2+ sample had an external quantum efficiency of 42%, comparable to the sample synthesized at 1750°C under 0.5 MPa N2 gas pressure by the GPS method reported in reference. The experimental results demonstrated that the microwave sintering method was also an interesting approach for synthesizing nitride phosphors, which promises lower firing temperature than those by carbothermal reduction and nitridation (CRN) methods, higher heating rate and shorter duration time compared with those by gas-pressure sintering.

Present work reviewed the discovery of new MAX phases since 2004. To date, there were new compounds synthesized in the Ti–Si–C (Ti4SiC3, Ti5Si2C3 and Ti7Si2C5), Ti–Al–C (Ti5Al2C3), Ti–Ge–C (Ti4GeC3, Ti5Ge2C3 and Ti7Ge2C5), Ti–Sn–C (Ti3SnC2), Ti–Ga–C (Ti4GaC3), V–Al–C (V3AlC2 and V4AlC3), V–Cr–Al–C ((V0.5Cr0.5)3AlC2 and (V0.5Cr0.5)5Al2C3), Ta–Al–Sn–C (Ta3Al0.6Sn0.4C2), Ta–Al–C (α-Ta4AlC3, β-Ta4AlC3, β-Ta6AlC5), Nb–Al–C (Nb4AlC3), and Ti–Nb–Al–C ((Ti,Nb)5AlC4) systems. The synthesis processes of new phases were introduced and the crystal parameters, atomic stacking sequences, as well as the atomic positions and basic physical and mechanical properties, of these new MAX phases were systemically described. Additionally, the possible directions and techniques of discovering new more MAX phases were summarized.Highlights► Present work reviewed the discovery of new MAX phases since 2004. ► The crystal structure, atomic positions, and properties of new MAX phases were described. ► The possible research directions and techniques of discovering new more MAX phases were summarized.

The high temperature creep behavior of carbon nanotube (CNT)/alumina was mediated by the surface chemical functionalization used for synthesis of composite powders. Non-covalent functionalized carbon nanotubes make composites ductile, but covalent approach leads composites that are creep-resistant. Oxygen vacancy mechanism is proposed to account for this mediation effect in this communication.

A robust solid state diffusion joining technique for SiC ceramics was designed with a thickness-controlled Ti interlayer formed by physical vapor deposition and joined by electric field-assisted sintering technology. The interface reaction and phase revolution process were investigated in terms of the equilibrium phase diagram and the concentration-dependent potential diagram of the Ti-Si-C ternary system. Interestingly, under the same joining conditions (fixed temperature and annealing duration), the thickness of the Ti interlayer determined the concentration and distribution of the Si and C reactants in the resulting joint layer, and the respective diffusion distance of Si and C into the Ti interlayer differentiated dramatically during the short joining process (only 5 min). In the case of a 100 nm Ti coating as an interlayer, the C concentration in the joint layer was saturated quickly, which benefited the formation of a TiC phase and subsequent Ti3SiC2 phase. The SiC ceramics were successfully joined at a low temperature of 1000 °C with a flexural strength of 168.2 MPa, which satisfies applications in corrosive environments. When the Ti thickness was increased to 1 μm, Si atoms diffused easily through the diluted Ti-C alloy (a dense TiC phase was not formed), and the Ti5Si3 brittle phase formed preferentially. These findings highlight the importance of the diffusion kinetics of the reactants on the final composition in the solid state reaction, particularly in the joining technique for covalent SiC ceramics.

In the present study, a nano-twinned microstructure is found in ion irradiated-Ti3AlC2 by the characterizations of high-resolution transmission electron microscopy and electron diffraction, combined with grazing incidence X-ray diffraction. No obvious difference in chemical composition was observed between pristine and irradiated samples. Ti3AlC2 transforms to a cation-disordered Ti-Al-C system with the rocksalt structure after ion irradiation, in which Ti and Al atoms randomly occupy the cation sites and C atoms occupy the anion sites with occupancy of 0.5. The as-irradiated Ti3AlC2 exhibits a nano-twinned structure and the twin thickness is in the range between 2 and 10 nm. Most of defects are located at or near the twin boundaries, which may be attributed to the segregation of Al. Based on the structural variations of complex oxides induced by ion irradiation and stability of solid solution (Ti, Al)xC, it is assumed that Ti3AlC2 has a natural tendency to accommodate the defects through the chemical order to chemical disorder, low symmetry to high symmetry structural transformation. The formation mechanisms of the nano-twinned structure are related to the irradiation-induced antisite defect of cations, disorder of C atoms, and lattice structure characteristic of Ti3AlC2. Because the nano-twinned structure may significantly improve the irradiation tolerance of Ti3AlC2 we study its stability under irradiation of Au ions at ∼150 dpa. Only a moderate increase in the twin thickness is found and the nano-twinned structure is basically retained, which demonstrates the great stability of nano-twinned structure and makes Ti3AlC2 a very promising irradiation tolerant material for advanced nuclear systems.

A robust strategy is explored to graft poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) brushes on two-dimensional vanadium carbide (V2C) materials through self-initiated photografting and photopolymerization (SIPGP). CO2 and temperature dual-responsive properties of PDMAEMA allow this hybrid to be used as a smart system for tuning the transmittance and conductivity of V2C.

MXenes, a novel family of two-dimensional metal carbides, are receiving intense attention for lithium-ion batteries (LIBs) and supercapacitors because they have high volumetric capacitance exceeding all carbon materials. However, serious interlayer stacking exists in MXene particles, which greatly decreases the electrical conductivity in the bulk and hinders the accessibility of interlayers to electrolyte ions. Thus, multi-stacked MXene particles exhibit low capacitance and poor rate capability. Herein, we report an effective strategy to directly improve the electrochemical performance of multi-stacked MXene (Ti3C2Tx) particles as LIB anode materials. It was successfully realized by growing conductive “carbon nanofiber (CNF) bridges” within the gaps of each Ti3C2Tx particle as well as the outside. With the help of these CNFs, the as-prepared Ti3C2/CNF particles exhibited significantly improved reversible capacity compared with pure Ti3C2Tx particles. More remarkably, even at an ultrahigh rate of 100 C, the capacity of Ti3C2/CNF hybrid particles was just slightly lower than that of pure Ti3C2Tx particles at 1 C, and there was no capacity decay after 2900 cycles at 100 C, demonstrating excellent rate capability and superior long-term stability at the ultrahigh rate.