Symmetry Breaking and Spin-Orbit Coupling for Individual Vacancy-Induced In-Gap States in MoS2 Monolayers.

Spins confined to point defects in atomically thin semiconductors constitute well-defined atomic-scale quantum systems that are being explored as single-photon emitters and spin qubits. Here, we investigate the in-gap electronic structure of individual sulfur vacancies in molybdenum disulfide (MoS2) monolayers using resonant tunneling scanning probe spectroscopy in the Coulomb blockade regime. Spectroscopic mapping of defect wave functions reveals an interplay of local symmetry breaking by a charge-state-dependent Jahn-Teller lattice distortion that, when combined with strong (≃100 meV) spin-orbit coupling, leads to a locking of an unpaired spin-1/2 magnetic moment to the lattice at low temperature, susceptible to lattice strain. Our results provide new insights into the spin and electronic structure of vacancy-induced in-gap states toward their application as electrically and optically addressable quantum systems.

Diatom Frustules Decorated with Co Nanoparticles for the Advanced Anode of Li-Ion Batteries.

Silica is regarded as a promising anode material for lithium-ion batteries (LIBs) because of its high theoretical capacity. However, large volume variation and poor electrical conductivity are limiting factors for the development of SiO2 anode materials. To solve this problem, combining SiO2 with a conductive phase and designing hollow porous structures are effective ways. In this work, The Co(II)-EDTA chelate on the surface of diatom biosilica (DBS) frustules and obtained DBS@C-Co composites decorated with Co nanoparticles by calcination without a reducing atmosphere is first precipitated. The unique three-dimensional structure of diatom frustules provides enough space for the volume change of silica during lithiation/delithiation. Co nanoparticles effectively improve the electrical conductivity and electrochemical activity of silica. Through the synergistic effect of the hollow porous structure, carbon layer and Co nanoparticles, the DBS@C-Co-60 composite delivers a high reversible capacity of >620 mAh g-1 at 100 mA g-1 after 270 cycles. This study provides a new method for the synthesis of metal/silica composites and an opportunity for the development of natural resources as advanced active materials for LIBs.

[Effects of curcumin on protein expression of glucose regulated protein 78 and caspase-12 of myocardial endoplasmic reticulum stress related factors in type 2 diabetes rats].

OBJECTIVE: To study the effect of curcumin on the expression of glucose regulated protein 78 kD(GRP78) and cysteinyl aspartate specific proteinase-12(caspase-12) of myocardial endoplasmic reticulum stress related factors in type 2 diabetes rats. METHODS: Type 2 diabetes rats model was established by high-fat drink feeding and one-time intraperitoneal injecting streptozotocin(35 mg/kg). After model rats were built, rats was randomly divided into diabetic model group and low dose of curcumin group(200 mg/kg), high dose of curcumin group(400 mg/kg) and captopril group(60 mg/kg) with 10 rats in each group. The rats in each group were ig administered with corresponding drugs once a day. Continuous administration for 12 w. The levels of fasting blood glucose(FBG) and lactate dehydrogenase(LDH), electrocardiogram and heart weight index(HWI) were measured respectively. The myocardial pathological changes were observed by HE staining. The levels of collagen fiber expression in myocardial tissue were performed by Masson staining. The protein expression levels of GRP78 and caspase-12 in myocardium of rats were observed by immunohistochemistry. RESULTS: The result showed that compared with control group, the levels of FBG and LDH of serum were increased obviously, HWI was increased, myocardial cells were hypertrophy, the collagen fibers of intercellular space of cell were increased, the protein expressions of GRP78 and caspase-12 of myocardium were increased in rats, myocardial cell apoptosis was increased in the model group(P<0. 05). Compared with model group, FBG and LDH levels and HWI were reduced, the collagen fiber of intercellular space were decreased, the protein expression levels of GRP78 and caspase-12 were lowered in high dose of curcumin group(P<0. 05). CONCLUSION: It indicates that Cur defends myocardium tissue in type 2 diabetes rats, which may be related to decreasing the level of blood glucose and the protein expressions of GRP78 and caspase-12, and blocking the ERS-initiated apoptotic.

Pressure-Engineered Structural and Optical Properties of Two-Dimensional (C4H9NH3)2PbI4 Perovskite Exfoliated nm-Thin Flakes.

Resolving the structure-property relationships of two-dimensional (2D) organic-inorganic hybrid perovskites is essential for the development of photovoltaic and photoelectronic devices. Here, pressure (0-10 GPa) was applied to 2D hybrid perovskite flakes mechanically exfoliated from butylammonium lead halide single crystals, (C4H9NH3)2PbI4, from which we observed a series of changes of the strong excitonic emissions in the photoluminescence spectra. By correlating with in situ high-pressure X-ray diffraction results, we examine successfully the relationship between structural modifications in the inorganic PbI42- layer and their excitonic properties. During the transition between Pbca (1b) phase and Pbca (1a) phase at around 0.1 GPa, the decrease in ⟨Pb-I-Pb⟩ bond angle and increase in Pb-I bond length lead to an abrupt blue shift of the excitonic bandgap. The presence of the P21/a phase above 1.4 GPa increases the ⟨Pb-I-Pb⟩ bond angle and decreases the Pb-I bond length, leading to a deep red shift of the excitonic bandgap. The total band gap narrowing of ∼350 meV to 2.03 eV at 5.3 GPa before amorphization, facilitates (C4H9NH3)2PbI4 as a much better solar absorber. Moreover, phase transitions inevitably modify the carrier lifetime of (C4H9NH3)2PbI4, where an initial 150 ps at ambient phase is prolongated to 190 ps in the Pbca (1a) phase along with enhanced photoluminescence (PL), originating from pressure-induced strong radiative recombination of trapped excitons.The onset of P21/a phase shortens significantly the carrier lifetime to 53 ps along with a weak PL emission due to pressure-induced severe lattice distortion and amorphization. High-pressure study on (C4H9NH3)2PbI4 nm-thin flakes may provide insights into the mechanisms for synthetically designing novel 2D hybrid perovskite based photoelectronic devices and solar cells.

Improving Polysulfides Adsorption and Redox Kinetics by the Co4 N Nanoparticle/N-Doped Carbon Composites for Lithium-Sulfur Batteries.

Improved conductivity and suppressed dissolution of lithium polysulfides is highly desirable for high-performance lithium-sulfur (Li-S) batteries. Herein, by a facile solvent method followed by nitridation with NH3 , a 2D nitrogen-doped carbon structure is designed with homogeneously embedded Co4 N nanoparticles derived from metal organic framework (MOF), grown on the carbon cloth (MOF-Co4 N). Experimental results and theoretical simulations reveal that Co4 N nanoparticles act as strong chemical adsorption hosts and catalysts that not only improve the cycling performance of Li-S batteries via chemical bonding to trap polysulfides but also improve the rate performance through accelerating the conversion reactions by decreasing the polarization of the electrode. In addition, the high conductive nitrogen-doped carbon matrix ensures fast charge transfer, while the 2D structure offers increased pathways to facilitate ion diffusion. Under the current density of 0.1C, 0.5C, and 3C, MOF-Co4 N delivers reversible specific capacities of 1425, 1049, and 729 mAh g-1 , respectively, and retains 82.5% capacity after 400 cycles at 1C, as compared to the sample without Co4 N (MOF-C) values of 61.3% (200 cycles). The improved cell performance corroborates the validity of the multifunctional design of MOF-Co4 N, which is expected to be a potentially promising cathode host for Li-S batteries.

Aurora-a confers radioresistance in human hepatocellular carcinoma by activating NF-κB signaling pathway.

BACKGROUND: Radiotherapy failure is a significant clinical challenge due to the development of resistance in the course of treatment. Therefore, it is necessary to further study the radiation resistance mechanism of HCC. In our early study, we have showed that the expression of Aurora-A mRNA was upregulated in HCC tissue samples or cells, and Aurora-A promoted the malignant phenotype of HCC cells. However, the effect of Aurora-A on the development of HCC radioresistance is not well known. METHODS: In this study, colony formation assay, MTT assays, flow cytometry assays, RT-PCR assays, Western blot, and tumor xenografts experiments were used to identify Aurora-A promotes the radioresistance of HCC cells by decreasing IR-induced apoptosis in vitro and in vivo. Dual-luciferase reporter assay, MTT assays, flow cytometry assays, and Western blot assay were performed to show the interactions of Aurora-A and NF-κB. RESULTS: We established radioresistance HCC cell lines (HepG2-R) and found that Aurora-A was significantly upregulated in those radioresistant HCC cells in comparison with their parental HCC cells. Knockdown of Aurora-A increased radiosensitivity of radioresistant HCC cells both in vivo and in vitro by enhancing irradiation-induced apoptosis, while upregulation of Aurora-A decreased radiosensitivity by reducing irradiation-induced apoptosis of parental cells. In addition, we have showed that Aurora-A could promote the expression of nuclear IkappaB-alpha (IκBα) protein while enhancing the activity of NF-kappaB (κB), thereby promoted expression of NF-κB pathway downstream effectors, including proteins (Mcl-1, Bcl-2, PARP, and caspase-3), all of which are associated with apoptosis. CONCLUSIONS: Aurora-A reduces radiotherapy-induced apoptosis by activating NF-κB signaling, thereby contributing to HCC radioresistance. Our results provided the first evidence that Aurora-A was essential for radioresistance in HCC and targeting this molecular would be a potential strategy for radiosensitization in HCC.

[Cyberknife stereotactic body radiotherapy for liver metastases from prostate cancer].

OBJECTIVE: To investigate the effectiveness and adverse effects of Cyberknife stereotactic body radiotherapy (SBRT) on liver metastases from PCa. METHODS: From June 2009 to September 2016, we treated 20 cases of PCa liver metastases by Cyberknife SBRT, at a total dose of 36 (30－50) Gy, on 1－3 liver metastatic lesions, for 3－5 times, with a prescription isodose line of 70－92%. We assessed the therapeutic effect according to the modified Response Evaluation Criteria in Solid Tumors (mRECIST), calculated the survival and disease-control rates using the Kaplan-Meier method, and analyzed the adverse events based on the National Cancer Institute Common Terminology Criteria for Adverse Events－Version 4.0 (CTCAE 4.0). RESULTS: Of all the cases treated, complete response (CR) was found in 8 (40.0%), partial response (PR) in 9 (45.0%), stable disease (SD) in 2 (10.0%), and progressive disease (PD) in 1 (5.0%), with a local control rate (CR+PR) of 85.0% and a disease-control rate (CR+PR+SD) of 95.0%. Among the 14 patients with elevated PSA, 10 (71.4%) showed a significant decrease after treatment. The median follow-up time was 17 months, the 1- and 2-year survival rates were 85.0% and 15.0%, respectively, and the median survival time of the 20 patients was 16.5 months (95% CI: 12.12－22.88). Cyberknife SBRT was well tolerated in all the patients, with only a few mild adverse events (mainly grades 1 and 2 but no 4 and 5) during the whole course of treatment. CONCLUSIONS: Cyberknife SBRT is safe and effective in the treatment of PCa liver metastases, with a high local control rate, and capable of reducing the PSA level and raising the long-term survival rate of the patients.

CYP2E1 Rsa Ι/Pst Ι polymorphism and lung cancer susceptibility: A meta-analysis involving 10,947 subjects.

The above article, published in the Journal of Cellular and Molecular Medicine on 14 September 2016 in Wiley Online Library (wileyonlinelibrary.com), and in Volume 19, pp. 2136-2142, has been retracted by agreement between the authors, the journal Editor in Chief, Stefan Constantinescu, and John Wiley & Sons Ltd. The retraction has been agreed due to unattributed overlap of the language used in the "Materials and method" and "Discussion" sections of this study and the following article published in Lung Cancer: "CYP2E1 Rsa I/Pst I polymorphism is associated with lung cancer risk among Asians" by Ping Zhan, Jing Wang, Yu Zhang, Li-Xin Qiu, Su-feng Zhao, Qian Qian, Shu-Zhen Wei, Li-Ke Yu and Yong Song, Volume 69, 2010, pages 19-25. REFERENCE Shen Z-T, Wu X-H, Li B, Shen J-S, Wang Z, Li J, Zhu X-X. CYP2E1 Rsa Ι/Pst Ι polymorphism and lung cancer susceptibility: a meta-analysis involving 10,947 subjects. J Cell Mol Med. 2015;19:2136-2142. https://doi.org/10.1111/jcmm.12579.

Water-Responsive Shape Recovery Induced Buckling in Biodegradable Photo-Cross-Linked Poly(ethylene glycol) (PEG) Hydrogel.

The phenomenon of recovering the permanent shape from a severely deformed temporary shape, but only in the presence of the right stimulus, is known as the shape memory effect (SME). Materials with such an interesting effect are known as shape memory materials (SMMs). Typical stimuli to trigger shape recovery include temperature (heating or cooling), chemical (including water/moisture and pH value), and light. As a SMM is able not only to maintain the temporary shape but also to respond to the right stimulus when it is applied, via shape-shifting, a seamless integration of sensing and actuation functions is achieved within one single piece of material. Hydrogels are defined by their ability to absorb a large amount of water (from 10-20% up to thousands of times their dry weight), which results in significant swelling. On the other hand, dry hydrogels indeed belong to polymers, so they exhibit heat- and chemoresponsive SMEs as most polymers do. While heat-responsive SMEs have been spotted in a handful of wet hydrogels, so far, most dry hydrogels evince the heat and water (moisture)-responsive SMEs. Since water is one of the major components in living biological systems, water-responsive SMMs hold great potential for various implantable applications, including wound healing, intravascular devices, soft tissue reconstruction, and controlled drug delivery. This provides motivation to combine water-activated SMEs and swelling in hydrogels together to enhance the performance. In many applications, such as vascular occlusion via minimally invasive surgery for liver cancer treatment, the operation time (for both start and finish) is required to be well controlled. Due to the gradual and slow manner of water absorption for water-activated SMEs and swelling in hydrogels, even a combination of both effects encounters many difficulties to meet the timerequirements in real procedures of vascular occlusion. Recently, we have reported a bioabsorbable radiopaque water-responsive shape memory embolization plug for temporary vascular occlusion. The plug consists of a composite with a poly(dl-lactide-co-glycolide) (PLGA) core (loaded with radiopaque filler) and cross-linked poly(ethylene glycol) (PEG) hydrogel outer layer. The device can be activated by body fluid (or water) after about 2 min of immersion in water. The whole occlusion process is completed within a few dozens of seconds. The underlying mechanism is water-responsive shape recovery induced buckling, which occurs in an expeditious manner within a short time period and does not require complete hydration of the whole hydrogel. In this paper, we experimentally and analytically investigate the water-activated shape recovery induced buckling in this biodegradable PEG hydrogel to understand the fundamentals in precisely controlling the buckling time. The molecular mechanism responsible for the water-induced SME in PEG hydrogel is also elucidated. The original diameter and amount of prestretching are identified as two influential parameters to tailor the buckling time between 1 and 4 min as confirmed by both experiments and simulation. The phenomenon reported here, chemically induced buckling via a combination of the SME and swelling, is generic, and the study reported here should be applicable to other water- and non-water-responsive gels.

Prognostic Significance of microRNA-7 and its Roles in the Regulation of Cisplatin Resistance in Lung Adenocarcinoma.

BACKGROUND: Previously, microRNA (miR)-7 has been reported to function as a tumor suppressor in human cancers, but the correlations of miR-7 expression with prognosis and cisplatin (CDDP) resistance in lung adenocarcinoma (LA) are unclear. Here, our aim is to determine the prognostic significance of miR-7 and its roles in the regulation of CDDP resistance in LA. METHODS: Quantitative real-time PCR (qRT-PCR) assay was performed to determine miR-7 expression in 108 paired of LA tissues and analyze its correlations with clinicopathological factors of patients. The patient survival data were collected retrospectively by Kaplan-Meier analyses, and multivariate analysis was performed using the Cox proportional hazards model to determine the prognostic significance of miR-7 expression. The effects of miR-7 expression on the chemosensitivity of LA cells to CDDP and its possible mechanisms were evaluated by MTT, flow cytometry, Western blot and luciferase assays. RESULTS: It was observed that the relative expression level of miR-7 in LA tissues was significantly lower than that in the adjacent normal tissues and low miR-7 expression level was closely associated with poorer tumor differentiation, advanced pathological T-factor, higher incidence of lymph node metastasis and advanced p-TNM stage. Also, patients with low miR-7 expression showed a shorter overall survival than those with high miR-7 expression, and multivariate analysis indicated that status of miR-7 expression was an independent molecular biomarker for predicting the overall survival (OS) of LA patients. In addition, upregulation of miR-7 increases the sensitivity of LA cells to CDDP via induction of apoptosis by targeting Bcl-2. CONCLUSIONS: Our finding for the first time demonstrates that low miR-7 expression may be an independent poor prognostic factor and targeting miR-7 may be a potential strategy for the reversal of CDDP resistance in LA.

Pressure-Induced Phase Transition in Weyl Semimetallic WTe2.

Tungsten ditelluride (WTe2 ) is a semimetal with orthorhombic Td phase that possesses some unique properties such as Weyl semimetal states, pressure-induced superconductivity, and giant magnetoresistance. Here, the high-pressure properties of WTe2 single crystals are investigated by Raman microspectroscopy and ab initio calculations. WTe2 shows strong plane-parallel/plane-vertical vibrational anisotropy, stemming from its intrinsic Raman tensor. Under pressure, the Raman peaks at ≈120 cm-1 exhibit redshift, indicating structural instability of the orthorhombic Td phase. WTe2 undergoes a phase transition to a monoclinic T' phase at 8 GPa, where the Weyl states vanish in the new T' phase due to the presence of inversion symmetry. Such Td to T' phase transition provides a feasible method to achieve Weyl state switching in a single material without doping. The new T' phase also coincides with the appearance of superconductivity reported in the literature.

Broadband and high modulation-depth THz modulator using low bias controlled VO2-integrated metasurface.

An active vanadium dioxide integrated metasurface offering broadband transmitted terahertz wave modulation with large modulation-depth under electrical control is demonstrated. The device consists of metal bias-lines arranged with grid-structure patterned vanadium dioxide (VO2) film on sapphire substrate. Amplitude transmission is continuously tuned from more than 78% to 28% or lower in the frequency range from 0.3 THz to 1.0 THz, by means of electrical bias at temperature of 68 °C. The physical mechanism underlying the device's electrical tunability is investigated and found to be attributed to the ohmic heating. The developed device possessing over 87% modulation depth with 0.7 THz frequency band is expected to have many potential applications in THz regime such as tunable THz attenuator.

TGF-ß1 rs1982073 polymorphism contributes to radiation pneumonitis in lung cancer patients: a meta-analysis.

Transforming growth factor beta 1(TGF-ß1) polymorphism was associated with radiation pneumonitis (RP) susceptibility, but their results have been inconsistent. The PubMed and CNKI were searched for case-control studies published up to Januray 01, 2016 was Data were extracted and pooled odds ratios (OR) with 95% confidence intervals (CI) were calculated. In this meta-analysis, we assessed eight publications involving 368 radiation pneumonitis cases and 855 controls of the association between TGF-ß1 T869C (rs1982073) and G915C (rs1800471) polymorphism and RP susceptibility. Our analysis suggested that TGF-ß1 T869C rs1982073 polymorphism was associated with lower RP risk for CT combined CC versus TT model (OR = 0.58, 95% CI = 0.43-0.77). However, for the G915C rs1800471 polymorphism, no association was found between the polymorphism and the susceptibility to RP in GC combined CC versus GG model (OR = 0.82, 95% CI = 0.50-1.35). These results from the meta-analysis suggest that T869C rs1982073 polymorphism of TGF-ß1 may be associated with RP risk, and there may be no association between G915C polymorphism and RP risk.

Generic Synthesis of Carbon Nanotube Branches on Metal Oxide Arrays Exhibiting Stable High-Rate and Long-Cycle Sodium-Ion Storage.

A new and generic strategy to construct interwoven carbon nanotube (CNT) branches on various metal oxide nanostructure arrays (exemplified by V2 O3 nanoflakes, Co3 O4 nanowires, Co3 O4 -CoTiO3 composite nanotubes, and ZnO microrods), in order to enhance their electrochemical performance, is demonstrated for the first time. In the second part, the V2 O3 /CNTs core/branch composite arrays as the host for Na(+) storage are investigated in detail. This V2 O3 /CNTs hybrid electrode achieves a reversible charge storage capacity of 612 mAh g(-1) at 0.1 A g(-1) and outstanding high-rate cycling stability (a capacity retention of 100% after 6000 cycles at 2 A g(-1) , and 70% after 10 000 cycles at 10 A g(-1) ). Kinetics analysis reveals that the Na(+) storage is a pseudocapacitive dominating process and the CNTs improve the levels of pseudocapacitive energy by providing a conductive network.

Tandem Copper-Catalyzed Propargylation/Alkyne Azacyclization/Isomerization Reaction under Microwave Irradiation: Synthesis of Fully Substituted Pyrroles.

A copper-catalyzed and microwave-assisted synthesis of fully substituted pyrroles has been developed. A series of pentasubstituted pyrroles, especially α-arylpyrroles, could be obtained in moderate to good yields (up to 93%) through a tandem propargylation/alkyne azacyclization/isomerization sequence from readily available ß-enamino compounds and propargyl acetates.

Stacking-Dependent Interlayer Coupling in Trilayer MoS2 with Broken Inversion Symmetry.

The stacking configuration in few-layer two-dimensional (2D) materials results in different structural symmetries and layer-to-layer interactions, and hence it provides a very useful parameter for tuning their electronic properties. For example, ABA-stacking trilayer graphene remains semimetallic similar to that of monolayer, while ABC-stacking is predicted to be a tunable band gap semiconductor under an external electric field. Such stacking dependence resulting from many-body interactions has recently been the focus of intense research activities. Here we demonstrate that few-layer MoS2 samples grown by chemical vapor deposition with different stacking configurations (AA, AB for bilayer; AAB, ABB, ABA, AAA for trilayer) exhibit distinct coupling phenomena in both photoluminescence and Raman spectra. By means of ultralow-frequency (ULF) Raman spectroscopy, we demonstrate that the evolution of interlayer interaction with various stacking configurations correlates strongly with layer-breathing mode (LBM) vibrations. Our ab initio calculations reveal that the layer-dependent properties arise from both the spin-orbit coupling (SOC) and interlayer coupling in different structural symmetries. Such detailed understanding provides useful guidance for future spintronics fabrication using various stacked few-layer MoS2 blocks.

Graphene quantum dots coated VO2 arrays for highly durable electrodes for Li and Na ion batteries.

Nanoscale surface engineering is playing important role in enhancing the performance of battery electrode. VO2 is one of high-capacity but less-stable materials and has been used mostly in the form of powders for Li-ion battery cathode with mediocre performance. In this work, we design a new type of binder-free cathode by bottom-up growth of biface VO2 arrays directly on a graphene network for both high-performance Li-ion and Na-ion battery cathodes. More importantly, graphene quantum dots (GQDs) are coated onto the VO2 surfaces as a highly efficient surface "sensitizer" and protection to further boost the electrochemical properties. The integrated electrodes deliver a Na storage capacity of 306 mAh/g at 100 mA/g, and a capacity of more than 110 mAh/g after 1500 cycles at 18 A/g. Our result on Na-ion battery may pave the way to next generation postlithium batteries.

CYP2E1 Rsa Ι/Pst Ι polymorphism and lung cancer susceptibility: a meta-analysis involving 10,947 subjects.

Many studies have examined the association between the CYP2E1 Rsa Ι/Pst Ι (rs3813867) polymorphism gene polymorphisms and lung cancer risk in various populations, but their results have been inconsistent. The PubMed and CNKI database was searched for case-control studies published up to October 2013. Data were extracted and pooled odds ratios (OR) with 95% confidence intervals (CI) were calculated. In this meta-analysis, we assessed 23 published studies involving comprising 4727 lung cancer cases and 6220 controls of the association between CYP2E1 Rsa Ι/Pst Ι polymorphism and lung cancer risk. For the homozygote c2/c2 and c2 allele carriers (c1/c2 + c2/c2), the pooled ORs for all studies were 0.73(95% CI = 0.62-0.84; P = 0.005 for heterogeneity) and 0.84 (95% CI = 0.77-0.92; P = 0.001 for heterogeneity) when compared with the homozygous wild-type genotype (c1/c1). In the stratified analysis by ethnicity, the same significantly risks were found among Asians and mixed population for both the c2 allele carriers and homozygote c2/c2. However, no significant associations were found in Caucasian population all genetic models. This updated meta-analysis suggests that CYP2E1 Rsa Ι/Pst Ι c2 allele is a decreased risk factor for the developing lung cancer among Asians and mixed population.

Bandgap-opened bilayer graphene approached by asymmetrical intercalation of trilayer graphene.

A novel graphene structure formed by asymmetrical intercalation of FeCl3 molecules into a trilayer graphene is reported. The trilayer graphene is divided into a single layer and a bilayer graphene by the inserted FeCl3 layer. Theoretical calculation shows that such graphene bilayers with broken inversion symmetry present a prominent opened bandgap of ∼0.13 eV.

A flexible alkaline rechargeable Ni/Fe battery based on graphene foam/carbon nanotubes hybrid film.

The development of portable and wearable electronics has promoted increasing demand for high-performance power sources with high energy/power density, low cost, lightweight, as well as ultrathin and flexible features. Here, a new type of flexible Ni/Fe cell is designed and fabricated by employing Ni(OH)2 nanosheets and porous Fe2O3 nanorods grown on lightweight graphene foam (GF)/carbon nanotubes (CNTs) hybrid films as electrodes. The assembled f-Ni/Fe cells are able to deliver high energy/power densities (100.7 Wh/kg at 287 W/kg and 70.9 Wh/kg at 1.4 kW/kg, based on the total mass of active materials) and outstanding cycling stabilities (retention 89.1% after 1000 charge/discharge cycles). Benefiting from the use of ultralight and thin GF/CNTs hybrid films as current collectors, our f-Ni/Fe cell can exhibit a volumetric energy density of 16.6 Wh/l (based on the total volume of full cell), which is comparable to that of thin film battery and better than that of typical commercial supercapacitors. Moreover, the f-Ni/Fe cells can retain the electrochemical performance with repeated bendings. These features endow our f-Ni/Fe cells a highly promising candidate for next generation flexible energy storage systems.