The world’s energy supply depends heavily on lithium-ion batteries due to the progressive depletion of non-renewable resources. The issue of raising the energy density of lithium-ion batteries must be addressed. We are all aware that the anode material is one area where lithium-ion batteries still have room for development. A new anode material, tin disulfide, not only has a high theoretical specific capacity (645 mAh g−1), but also allows the formation of different microstructures through variable growth rates. In this study, we created three-dimensional nano-spheres of SnS2 using solid-phase synthesis and then wrapped SnS2 and B4C in OUCNTs (SnS2/B4C@OUCNT) using hydrothermal synthesis. Ascribed to the synergy between the highly chemical active B4C and the conductive carbon network of the OUCNTs, SnS2/B4C@OUCNT (149 Ω) effectively overcomes the drawback of high impedance of pure SnS2 (307 Ω) while exhibiting high capacity and cyclic stability. After 100 cycles at a current density of 100 mA g−1, this material displayed good electrochemical properties as the anode for lithium-ion batteries, obtaining a reversible capacity of 1024.7 mAh g−1 and a coulombic efficiency of 98.01%. The discharge capacity is 854.7 mAh g−1 with a coulombic efficiency of 98.57% after 200 cycles at 1000 mA g−1.

Ni-rich cathode materials are considered one of the most promising electrode materials due to high capacity and low cost. However, the instability of the lattice suppresses its further application. In this work, we doped Zr at the Ni site of LiNiO2 by first-principle simulations based on density functional theory and explored the mechanism of doping for enhancing the electrochemical performance. The results show that Zr doping can effectively improve the cycle stability, electronic conductivity, intercalation potential, and diffusion rate of Li-ions. The theoretical study gives an insight into the microscopic mechanism of Zr doping to enhance the electrochemical performance of LiNiO2 and is helpful for the design of high performance LiNiO2-based cathode materials.

In this work, novel mesoporous tetrakaidecahedron-like α-Fe2O3 nanocrystals have been designed in high yield through a simple hydrothermal method. The growth mechanism of mesoporous tetrakaidecahedron-like α-Fe2O3 nanocrystals was first investigated in detail based on the FESEM images and XRD results of the intermediate products. The electrochemical performance demonstrates that the mesoporous tetrakaidecahedron-like α-Fe2O3 nanocrystal electrode displays enhanced pseudocapacitive properties with a high specific capacitance of 245 F g−1 at 2 A g−1 and good capacitance retention of 83.9% after 2000 continuous charge–discharge cycles, implying that the porous tetrakaidecahedron-like α-Fe2O3 nanocrystals have great potential applications for supercapacitors.

High-performance gel polymer electrolytes based on polyethylene oxide/polymethyl methacrylate (PEO/PMMA) incorporating different weight percentage of single-layered graphene oxide (GO) nanosheets were prepared by a solution method for dye-sensitized solar cell applications. The measured ionic conductivity and thermal properties of electrolytes exhibited that these characteristics can be increased with the introduction of graphene oxide into PEO/PMMA based gel electrolyte. The results revealed that the highest ionic conductivity of gel polymer electrolyte was 14.5 mS·cm−1 at 1 wt% of graphene oxide nanosheets. Solar cell composed of optimized polymer gel electrolyte (PEO/PMMA/GO-1) revealed a 6.98% photon conversion efficiency, which was more than neat PEO/PMMA gel electrolyte (4.92%). This finding can be related to the higher ionic conductivity of the composite electrolytes as a result of the addition of graphene oxide nanosheets. Electrochemical impedance analysis showed that charge recombination resistance of gel electrolyte can be increased in the presence of graphene nanosheets. The long-term stability study showed that after 600h of testing, the optimized solar cell (PMMA/PEO/GO-1) had very significant durability as compared to the cell fabricated with liquid electrolyte.

In this paper, NiMo–MOF and CoMo–MOF bimetallic nanomaterials were synthesized respectively for constructing electrochemical glucose sensors. SEM, TEM, Mapping, XPS, BET, and XRD were used to investigate the morphology of the nanoparticles. The Nafion/NiMo–MOF/GCE and Nafion/CoMo–MOF@GCE non-enzymatic glucose sensors were constructed by modifying the material on the glassy carbon electrode. The results of electrochemical detection showed that the CoMo–MOF material not only greatly enhanced the stability and sensitivity of the sensor but also broadened the detection linear range more than NiMo–MOF. The Nafion/CoMo–MOF@GCE displays a higher sensitivity (246.71 μA mM−1 cm−2) and lower detection limit (26.17 μM) in a linearity range of 0 to 15 mM. However, Nafion/NiMo–MOF@GCE shows the sensitivity of 184.40 μA mM−1 cm−2 with LOD of 22.23 μM, with a linearity range of 0 to 5 mM. The two sensors had good stability and reproducibility, and also showed extremely high reliability and practicability in the actual sample detection (RSD did not exceed 3%).

In this work, carbon-supported Pt-Fe catalysts (Pt-Fe/C) have been synthesized to determine the electrochemical activity toward oxygen reduction reaction (ORR). Compared to the Pt/C catalyst, the Pt-Fe/C catalyst showed around 23% less area-specific activity but 8.6% more mass activity. These findings suggest the possibility to develop a catalyst that is both more active and cost-efficient than platinum. Furthermore, Pt-Fe/C catalyst was successfully compared as a cost-effective catalyst alternative to the Pt/C catalyst.

Transition metal selenide (TMS) materials are potential leading anode materials for sodium-ion batteries (SIBs) because of their superior operating voltage and theoretical capacity. Herein, a simple bimetallic selenide hydrothermal strategy is used to synthesize (Ni,Co)Se2 (NCS) nanostructures by regulating with polyethylene glycol 500 (PEG-500). The material morphology assessment indicated that the prepared NCS materials exhibit a network structure formed by stacked nanoparticles. Remarkably, part of the NCS nanoparticles (marked as NCS10) grew into smooth polygonal nanosheets when 10 ml PEG-500 was added, which has presented a specific capacity of 357.7 mAh·g−1 at 0.1 A·g−1 after 100 cycles. Meanwhile, it delivered an excellent rate performance of 318.2 mAh·g−1 at 5 A·g−1. It is the synergized effect of ultrathin NCS10 polygonal nanosheets and special porous network structure formed by nanoparticles that ensure favourable structural stability for the insertion and deinsertion of Na+ during sodiation/desodiation reaction, and the superior sodium storage rate can be attributed to the pseudocapacitance contribution. The excellent electrochemical properties of NCS nanomaterials have verified that they are promising anode materials for SIBs.

Solid-state electrolyte is a crucial component of all-solid-state batteries. Composite solid electrolytes are gaining attention for their ability to combine the high ionic conductivity and mechanical strength of inorganic solid-state electrolytes with the flexibility and interfacial compatibility of polymer solid electrolytes. However, agglomeration in composite solid electrolytes caused by inorganic fillers with high surface energy seriously affects the performance of composite solid electrolytes. To address this issue, nonionic fluorocarbon surfactant FC-4430 was added to the Li6.4La3Zr1.4Ta0.6O12 (LLZTO)/polyethylene oxide (PEO) composite solid electrolyte to enhance the wettability between LLZTO and the PEO matrix, resulting in the uniform dispersion of higher LLZTO content in PEO and improved ionic conductivity of the composite solid electrolyte. In addition, a smoother and flatter surface of the composite solid electrolyte is obtained, which improves the electrolyte/electrode interfacial contact. With the addition of 0.3 wt% FC-4430, the highest ionic conductivity of the composite solid electrolyte at 60 °C reaches 6.46 × 10−4 S/cm. The lithium-ion mobility of the composite solid-state electrolyte at room temperature is 0.69, and a voltage stability window is up to 5.0 V. The assembled LFP all-solid-state batteries show the initial discharge specific capacities of 158.4 mAh/g and 139.5 mAh/g at rate of 0.5 C and 1 C, respectively, as well as capacity retention of 96.4% and 90.9% after 300 cycles at 60 °C. Composite solid electrolytes also show improved mechanical properties and thermal stability.

The Sr(Co0.9M0.1)O3-δ (M = Co, Y, Nb) composite oxides were prepared by the simple solid-state reaction method, and the pure Sr(Co0.9Nb0.1)O3-δ (M = Nb) perovskite-type oxide was obtained. It was further characterized by the powder X-ray diffraction (XRD), thermogravimetry/differential thermal analysis (TG/DTA), and scanning electron microscope/energy-dispersive X-ray spectra (SEM/EDX) techniques and demonstrated that the structural stability of the perovskite-type Sr(Co0.9Nb0.1)O3-δ oxide is improved greatly by Nb cation doping. The high-temperature oxygen sorption/desorption properties of the perovskite-type Sr(Co0.9Nb0.1)O3-δ were studied by TG in a flowing air stream between 350 and 950 ℃, and a high oxygen sorption capacity of 10.5 mL O2 (STP)/g oxide was obtained for the Sr(Co0.9Nb0.1)O3-δ oxide.Graphical Abstract

Low-cost and efficient electrode materials play a key role in improving the performance of lithium-ion battery. In this paper, the single-crystalline LiMn2O4 nanoparticles were synthesized through the gel combustion method assisted by microwave followed by calcination treatment. High-quality single-crystallinity characteristics of the LiMn2O4 precursor powder could be well retained after a high-temperature (990 °C) solid-state reaction. When valued as the working electrode materials for lithium-ion battery, they presented the exceptional electrochemical performances including the high specific capacity for an initial discharge of 120.53 mAh/g, the good rate capability with the retention of 65.52% at 5 C of the capacity at 0.2 C, and better cyclic performance with a capacity retention ratio of 90.01% after 300 cycles. The outstanding electrochemical performance of our prepared single-crystalline LiMn2O4 nanoparticles was perceived as the hopeful electrode materials for high-power lithium-ion battery.

One of the most effective methods for resolving the energy and environmental crises facing modern society is the electrocatalytic reduction of carbon dioxide. To achieve great energy efficiency and excellent selectivity for the target product, however, two internal difficulties must be overcome: the high energy barrier needed to activate carbon dioxide and the linear proportionate relationship between the combinations of intermediate adsorbents. A triazine-based controllable microporous carbon nanospheres supported metal monoatomic Ni electrocatalyst (Ni SACs/MC NPs) with clear and stable structure, high specific surface area, and integrated CO2 capture, and catalysis was created using a straightforward self-assembly strategy of aqueous lotion polymerization. This catalyst can function effectively in strong alkaline electrolytic solutions. The single-atom nickel loading amount is up to 15.38 wt%, which can show up to nearly 100% CO selectivity at ~ 200 mA cm−2 current. After more than 10 h of stability test, its catalytic performance has no obvious performance degradation, showing high stability. The excellent activity and stability of Ni-SACs/MC NPs can be attributed to the porous structure of the material, Ni metal single-atom and metal-carrier electronic effect (EMSI). The synthesis method of this material also provides a reference for the synthesis of other single-atom materials.Graphical Abstract

In the present work, cerium oxide nanorods were grown on fluorine-doped tin oxide substrates by the hydrothermal process with growth fluid concentrations from 0.06 to 0.09 M and maintaining the urea content constant at 0.5 M. Optimized tungsten oxide thin films were deposited on these hydrothermally grown cerium oxide nanorods by using DC sputtering process. The developed tungsten oxide-cerium oxide nanostructured hybrid films were characterized for their structural, morphological, optical, and electrochromic (EC) properties, by using various analytical techniques. It was observed that with the increase of growth fluid concentration, the cerium oxide nanorods (CeO2 NRs) become thinner and longer and decrement in transmittance. The highest diffusion coefficient (8.07 ×10−14 cm2/s) in the hybrid films formed with 0.08 M, and the highest coloration efficiency (13.88 cm2/C) in 0.06 M growth fluid concentrations was observed. The influence of CeO2 NRs on WO3 electrochemical performance observed in this study definitely helps in the selection of proper doping components and concentrations for power-saving optoelectronic devices.

Lithium-sulfur batteries are considered as the most promising energy storage devices owing to their high theoretical energy density and theoretical specific capacity. But some problems hinder their practical application, including low electronic conductivity and polysulfide migration during discharge–charge process. In this work, C/MoS2 heterostructure composites constructed by in situ growth of MoS2 on porous carbon are developed as the sulfur host for lithium-sulfur batteries. The introduction of porous carbon could improve the electronic conductivity of the cathode, as well as the C/MoS2 heterostructure could accelerate the redox kinetics and inhibit the shuttle effect via the adsorption with polysulfide. All of these advantages could improve the electrochemical performance of the lithium-sulfur batteries. This work demonstrates that the employment of hybrid composites as sulfur host is a promising method to improve the electrochemical performance of lithium-sulfur batteries.

A novel optimised solid biopolymer electrolyte (SBE) was fabricated based on flaxseed gum (FG) with various concentration of ammonium chloride (NH4Cl) via solution casting technique. The characterizations of the SBE film were made using X-ray diffraction (XRD), Fourier transform infrared (FTIR), differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and electrochemical impedance spectroscopy (EIS). The XRD pattern reveals significant enhancement of amorphous nature with incorporation of NH4Cl. The existence of interaction between FG and NH4Cl was proven through FTIR. DSC predicts the glass transition temperature Tg to be 52.34 °C. On addition of 0.3 M wt% NH4Cl, the EIS showed increase in ionic conductivity from 2.95 × 10−9 S/cm (pristine FG) to 1.13 × 10−4 S/cm. The conductivity trend was further verified by dielectric analysis, which proved the non-Debye behaviour. Using the highest conducting SBE film, the open circuit voltage was found to be 1.89 V at 353 K.

The non-volatility, controllable characteristics of ionic liquids (ILs) make them potential materials for various applications. The use of functionalized ionic liquids can improve their physicochemical properties. Propanenitrile imidazolium-based ionic liquids (C2CN Rim) with different functional groups, R (allyl, ethoxyl, and benzyl), and incorporating dioctylsulfosuccinate (DOSS) anion were prepared. The elemental analysis and 13C and 1H NMR results confirmed the synthesized IL structures. The density, viscosity, and refractive index of these ILs were measured over a temperature range of 293.15 to 353.15 K. Furthermore, several thermodynamic properties including the thermal expansion coefficient, molar refraction, standard molar entropy, and lattice energy were estimated for these ILs. Findings show that ILs have lower densities, similar refractive indices, higher viscosities, and lower decomposition temperature compared to their analogous incorporating only nitrile functionality. Also, the ILs showed a weak temperature dependency on the thermal expansion coefficients, αp = 4.75 × 10−4 to 5.25 × 10−4 K−1. These findings provide valuable insights into the properties and potential applications of propanenitrile imidazolium-based ionic liquids incorporating DOSS anion.

Perovskite solar cells (PSCs) evolved as a third-generation photovoltaic technology device due to their flexible tunability of optoelectronic properties, low-cost fabrication protocols, with remarkable power conversion efficiency to compete with the present solar cell market. However, interfacial and deep-level defects in the perovskite layer limit the devices’ power conversion efficiency (PCE). Additive engineering is one of the most holistic approaches to overcoming these issues. In this article, we report the additive engineering of the perovskite layer with cellulose-based synthetic additive hydroxypropyl methylcellulose (HPMC) to investigate its optical absorption, surface morphology, and electrical performances. Herein, we fabricated a solar cell layer architecture consisting of FTO/mesoscopic TiO2/MAPbI3/carbon/Ag. Optical, morphological, and structural properties were examined via UV-Vis spectroscopy, field emission scanning electron microscopy, and X-ray diffraction analyses. Furthermore, photoluminescence (PL) spectra were analyzed to investigate the lifetime of the photogenerated charge carrier. Moreover, the interaction between the functional groups of HPMC and with perovskite precursor solution was characterized via Fourier-transform infrared spectroscopy (FTIR). Finally, the electrical performance of the solar cells was analyzed under simulated AM 1.5G solar illumination using 100 mW.cm–2 light intensity. The surface morphology of the perovskite solar cell was modified by incorporating HPMC additive into the perovskite. This HPMC additive-based perovskite showed improved PCE compared to a non-HPMC-based perovskite device. Moreover, the HPMC additive perovskite device improves film morphology with 13.37% of PCE and low hysteresis behavior. This method provides a facile route to fabricate low-defect PSCs through a low-cost solution processed at room temperature with the help of defect-minimized coherent interfaces.

Solid-state membranes with high ionic conductivity and good mechanical and electrochemical properties are desirable for next-generation lithium-ion batteries. In this present work, lithium-ion conducting polymer membranes based on ABC type triblock co-polymer, “poly(vinylidene chloride-co-acrylonitrile-co-methyl methacrylate)–lithium nitrate (P(VDC-co-AN-co-MMA)-LiNO3 or TBC),” have been prepared in different compositions by the solution casting technique. Ethylene carbonate has been incorporated to study its effect as a plasticizer. X-ray diffraction study confirms the decrease in crystalline nature and the plasticized membrane 20 wt.% PVDC…:80 wt.% LiNO3:0.6 wt.% ethylene carbonate (TBC-5) exhibits a high degree of amorphous nature and the same membrane has shown a low Tg value. Polymer membrane TBC-5 has shown maximum ionic conductivity of 1.12 ± 0.04 × 10−2 S cm−1 at 303 K. The TBC-5 also has shown a wide electrochemical stability window of 3.98 V. The primary lithium-ion battery constructed with TBC-5 as an electrolyte exhibits excellent stability in performing load discharge testing and LED testing.

Design and synthesis of high-performance and low-cost electrocatalysts for methanol oxidation reaction (MOR) are of great significance in energy conversion applications. In this work, g-NiO/CuO composites with high catalytic performance for MOR are successfully synthesized by a template method using g-C3N4 flakes as the sacrificial template. NiO nanoparticles are dispersed uniformly on the surface of the pine needle-liked CuO substrate, resulting in a synergistic effect which can enhance the electrocatalytic MOR activity and stability of g-NiO/CuO catalysts. The catalyst shows a maximum peak current density of 159 mA cm−2 and also long-term stability. The bimetal-oxide-synergistic strategy in this work highlights a promising way for the design of catalysts with high electrochemical performance for direct methanol fuel cells (DMFCs).

Fe3O4 and Fe3O4/NiO heterostructures were successfully prepared by a simple one-step solvothermal method. The morphology of Fe3O4/NiO heterostructures is flower-like spheres composed of nanosheets with a thickness of 10–20 nm. As anode material for lithium-ion batteries (LIBs), the electrochemical performance of the Fe3O4 and Fe3O4/NiO heterostructures are comparatively investigated. At current density of 100 mA g−1, the Fe3O4/NiO heterostructures can maintain 1021 mAh g−1 after 100 cycles. The discharge capacity can still maintain at 500 mAh g−1 and the coulomb efficiency is always stable at 99.6% after 1000 cycles at 1 A g−1. The Fe3O4/NiO heterostructures also have lower impedance and better rate capability, compared with the bare Fe3O4 electrode. Moreover, the electrochemical properties of the Fe3O4/NiO heterostructures can be further improved when the new binder CMC-Li is used. At 100 mA g−1, it can still maintain 1544 mAh g−1 after 100 cycles. These loose-layered nanosheets can effectively alleviate the volume expansion of materials in the process of charge and discharge. Meanwhile, the large surface area can provide more reaction sites. The ultra-thin nanosheet can also reduce the diffusion distance of lithium ions, so that the Fe3O4/NiO heterostructures have excellent performance in lithium-ion batteries.

Doping with oxygen and nitrogen in graphite felt (GF) is critical for enhancing the activity of the electrode material in vanadium redox flow batteries (VRFB). In this paper, we present a combined approach that utilizes Fe etching and nitrogen functionalization by means of K2FeO4 and NH3 to modify the surface structure of graphite fibers. The results show that the innovative approach enhances the disordered structure of the surface carbon of GF and substantially improves the oxygen and nitrogen functionalized groups. This modified GF is completely hydrophilic, and its assembled electrode energy efficiency is 80.08% at a current density of 80 mA∙cm−2, compared with 69.87% for the pristine GF. The energy efficiency of the modified GF was maintained at 81.8% after 50 charge-discharge cycles. This can be attributed to the reduced internal resistance of these modified GF electrode as well as to the improved mass transport and charge redox exchange towards VO2+/VO2+ redox couple. The combined approach of Fe etching and nitrogen functionalization significantly enhances the electrochemical activity of the GF electrode. This improves the performance of the VRFB.