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A porous organic polymer (POP) has been developed for dual-ion storage in all organic symmetric rechargeable batteries. The triphenylamine-pyrene-based POP could host sodium and hexafluorophosphate ions acting as the anode and the cathode, respectively, through the adsorption-intercalation and insertion mechanism. The current study highlights the concept of widening the potential window of a dual ion battery by judicious selection of the constituent moieties. [ABSTRACT FROM AUTHOR]

Li-ion batteries with conversion type anode are attractive choice, for electric vehicles and portable electronic devices, because of their high theoretical capacity and cycle stability. On the contrary, enormous volume change during lithiation/delithiation and irreversible conversion reaction limits use of such anodes. To overcome these challenges, incorporating nano-sized SnO x on flexible carbonaceous matrix is an efficient approach. A facile and scalable fabrication of SnO nanodisc decorated on SnO2 quantum dots embedded carbon (SnO x @C) is reported in the present study. Detailed structural and morphological investigation confirms the successful synthesis of SnO x @C composite with 72.3 wt% SnO x loading. The CV profiles of the nanocomposite reveal a partial reversibility of conversion reaction for the active materials SnO x. Such partial reversible conversion enhances the overall capacity of the nanocomposite. It delivers a very high discharge capacity of 993 mAh gâˆ'1 at current density of 0.05 A gâˆ'1 after 200 cycles; which is 2.6 times higher than that of commercial graphitic anode (372 mAh gâˆ'1) and very close to the calculated capacity of the SnO x @C composite. This unique nanocomposite remarkably improves Li storage performance in terms of reversible capacity, rate capability and cycling performance. It is established that such engineered anode can efficiently reduce the electrode pulverization and in turn make conversion reaction of tin partially reversible. [ABSTRACT FROM AUTHOR]

In this work, composite of Mo2C embedded in carbon and decorated on reduced graphene oxide (rGO) was synthesised by simple and inexpensive method followed by reduction‐carbonisation for anode material for sodium ion battery. A series of techniques were utilized for structural, morphological and electrochemical characterizations. The electrochemical behaviour of Mo2C composites as anode materials of sodium ion battery was explored thoroughly. Mo2C embedded in carbon and decorated on rGO nanosheets (Mo2C/C/rGO) showed enhanced electrochemical performance in all respects. This unique design of Mo2C/C/rGO exhibited specific capacity of 498 mAh g−1 at 50 mA g−1 current density and it retained 96.4 % of its initial capacity after 750 cycles. The added carbon and rGO nanosheets not only enhanced electronic conductivity but also minimized the adverse effect arises due to volume expansion during charging and discharging. The full cell fabricated with this rationally designed anode against NaNi0.5Mn0.3Co0.2O2 cathode delivered specific capacity of approximately 107 mAh g−1 at 50 mA g−1. Theoretical studies disclose that strong interaction between Mo2C and graphene modifies the band structure and geometrical parameters which facilitates sodium ion movement in the composite. These results shed light on Mo2C/C/rGO as future potential anode material for sodium ion battery application. [ABSTRACT FROM AUTHOR]

We have prepared nano-structured In-doped (1 mol %) LiFePO4/C samples by sol-gel method followed by a selective high temperature (600 and 700 °C) annealing in a reducing environment of flowing Ar/H2 atmosphere. The crystal structure, particle size, morphology, and magnetic properties of nano-composites were characterized by X-ray diffraction (XRD), scanning electron microsopy (SEM), transmission electron microscopy (TEM), and 57Fe Mössbauer spectroscopy. The Rietveld refinement of XRD patterns of the nano-composites were indexed to the olivine crystal structure of LiFePO4 with space group Pnma, showing minor impurities of Fe2P and Li3PO4 due to decomposition of LiFePO4. We found that the doping of In in LiFePO4/C nanocomposites affects the amount of decomposed products, when compared to the un-doped ones treated under similar conditions. An optimum amount of Fe2P present in the In-doped samples enhances the electronic conductivity to achieve a much improved electrochemical performance. The galvanostatic charge/discharge curves show a significant improvement in the electrochemical performance of 700 °C annealed In-doped-LiFePO4/C sample with a discharge capacity of 142 mAh.g-1 at 1 C rate, better rate capability (~128 mAh.g-1 at 10 C rate, ~75% of the theoretical capacity) and excellent cyclic stability (96% retention after 250 cycles) compared to other samples. This enhancement in electrochemical performance is consistent with the results of our electrochemical impedance spectroscopy measurements showing decreased charge-transfer resistance and high exchange current density. [ABSTRACT FROM AUTHOR]

Flexible inorganic–organic magneto-electric (ME) nanocomposite films (PVDF, PVDF-GO, PVDF-Fe3O4 and PVDF-GO-Fe3O4), composed of well-dispersed graphene oxide (GO 5 wt%) and magnetic Fe3O4 nanoparticles (5 wt%) embedded into a poly(vinylidene-fluoride) (PVDF) matrix, have been prepared by a solvent casting route. The magnetic, ferroelectric, dielectric, magneto-dielectric (MD) coupling and structural properties of these films have been systematically investigated. Magnetic (Ms = 2.21 emu g−1) and ferroelectric (P = 0.065 μC cm−2) composite films of PVDF-GO-Fe3O4 (PVDF loaded with 5% GO and 5% Fe3O4) with an MD coupling of 0.02% at room temperature (RT) showed a three times higher dielectric constant than that of the pure PVDF film, with a dielectric loss as low as 0.6. However, the PVDF-Fe3O4 film, which exhibited improved magnetic (Ms = 2.5 emu g−1) and MD coupling (0.04%) properties at RT with a lower dielectric loss (0.3), exhibited decreased ferroelectric properties (P = 0.06 μC cm−2) and dielectric constant compared to the PVDF-GO-Fe3O4 film. MD coupling measurements carried out as a function of temperature on the multi-functional PVDF-GO-Fe3O4 film showed a systematic increase in MD values up to 100 K and a decrease thereafter. The observed magnetic, ferroelectric, dielectric, MD coupling and structural properties of the nanocomposite films are attributed to the homogeneous dispersion and good alignment of Fe3O4 nanoparticles and GO in the PVDF matrix along with a partial conversion of nonpolar α-phase PVDF to polar β-phase. The above multi-functionality of the composite films of PVDF-Fe3O4 and PVDF-GO-Fe3O4 paves the way for their application in smart multiferroic devices. [ABSTRACT FROM AUTHOR]

The quest for new multiferroic materials is on the rise due to their potential application in spintronics and futuristic multiple state memory devices. Here we report the microwave synthesis of iron/gadolinium co-doped PbTiO3 nanorods, which display multiferroic behavior. Both the undoped and doped PbTiO3 samples have been characterized using powder X-ray diffraction, energy dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) techniques. The morphology of the samples has been studied using transmission electron microscopy (TEM) and high resolution transmission electron microscopy (HRTEM), which confirmed the formation of nanorods. The substitution of Fe ions for Ti and Gd ions for Pb enhances the ferromagnetic and ferroelectric properties of this system. The reasons for this observation have been explored in detail. The ferroelectric, magnetic and magneto-capacitive measurements at room temperature substantiate the multiferroic nature of the codoped samples with significant magnetoelectric coupling observed in case of nano PbTiO3:Gd3+(0.5%):Fe3+(5%). [ABSTRACT FROM AUTHOR]

Li-ion batteries with conversion type anode are attractive choice, for electric vehicles and portable electronic devices, because of their high theoretical capacity and cycle stability. On the contrary, enormous volume change during lithiation/delithiation and irreversible conversion reaction limits use of such anodes. To overcome these challenges, incorporating nano-sized SnO x on flexible carbonaceous matrix is an efficient approach. A facile and scalable fabrication of SnO nanodisc decorated on SnO 2 quantum dots embedded carbon (SnO x @C) is reported in the present study. Detailed structural and morphological investigation confirms the successful synthesis of SnO x @C composite with 72.3 wt% SnO x loading. The CV profiles of the nanocomposite reveal a partial reversibility of conversion reaction for the active materials SnO x . Such partial reversible conversion enhances the overall capacity of the nanocomposite. It delivers a very high discharge capacity of 993 mAh g -1 at current density of 0.05 A g -1 after 200 cycles; which is 2.6 times higher than that of commercial graphitic anode (372 mAh g -1 ) and very close to the calculated capacity of the SnO x @C composite. This unique nanocomposite remarkably improves Li storage performance in terms of reversible capacity, rate capability and cycling performance. It is established that such engineered anode can efficiently reduce the electrode pulverization and in turn make conversion reaction of tin partially reversible., (© 2022 IOP Publishing Ltd.)

Combined photoluminescence (PL) and dielectric studies have been carried out on both undoped and Eu 3+ doped LiNbO 3 compounds for their potential application in optical-electrical integration for the first time. Special focus has been given to simultaneously tuning both these physical properties. A PL study reveals that the blank compound is a blue emitting material, while upon doping with Eu 3+ ions, the emitting color can be tuned from blue to red upon changing the excitation wavelength. Interestingly, the electrical property measurement of this ferroelectric compound showed that upon doping with Eu 3+ ions, the remnant polarization was increased significantly. Density Functional Theory (DFT) based calculations were carried out to explain both the optical and electrical properties. It has been found that different defect centers are responsible for the bluish host emission while Eu 3+ ions are energetically preferred to occupy the Nb site and gives rise to red emission. The DFT based results also showed that Eu 3+ ions induced more distortion into the nearby Nb-site, which is responsible for enhancement of the remnant polarization. Stark-splitting patterns in the PL study also showed that the point symmetry of LiNbO 3 upon Eu 3+ doping changes from C 6v to D 3 , which indicates that the structure becomes less symmetric. Overall, the study presents a novel approach to designing multifunctional materials for optical-electrical integration application and to tuning their physical properties simultaneously in the desired range., Competing Interests: All authors are hereby declared that there is no conflict of interest., (This journal is © The Royal Society of Chemistry.)