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The main aim of this research is the examination of the physicochemical properties and their impact on the electrochemical activity of carbon materials obtained from the starch of different botanical origin (SCs). The obtained materials are compared to graphene nanoplatelets (GNPs) of different particle sizes (5 and 25 µm) applied as an anode active material for high-performance lithium-ion cells. SCs were obtained via thermal carbonization and this process enables an obtainment of better sorption properties compared to GNPs. The excellent electrochemical properties are mainly attributed to the good DLi+ (3.03 × 10−13–7.64 × 10−11 cm2 s−1 for SCs and 7.60 × 10−13–5.42 × 10−12 cm2 s−1 for GNPs) and relatively small resistances (EIS). However, the primary focus is on the specific capacity and cyclability. The capacity retentions of CSC cycled at 1 mA g−1, 10 mA g−1, 50 mA g−1, 1 mA g−1 for 50 cycles are 98%, 99%, 96%, 94% with specific capacities equal to 820, 800, 790, 1000 mAh g−1, respectively. The 5GNPs and 25GNPs may present a much smaller reversible capacity of 650, 600 mAh g−1 at 10 mA g−1. The thermal modification process of starches is simple, safe and widely applied, providing new paths for rational engineering of anode materials for LIBs. Moreover, the applied materials are easily available worldwide and are promising in the well-known Green Chemistry aspect making the cells more biodegradable. Graphic Abstract

The aspect of safety in electronic devices has turned out to be a huge challenge for the world of science. Thus far, satisfactory power and energy densities, efficiency, and cell capacities have been achieved. Unfortunately, the explosiveness and thermal runaway of the cells prevents them from being used in demanding applications such as electric cars at higher temperatures. The main aim of this review is to highlight different electrolytes used in lithium-ion cells as well as the flammability aspect. In the paper, the authors present liquid inorganic electrolytes, composite polymer–ceramic electrolytes, ionic liquids (IL), polymeric ionic liquids, polymer electrolytes (solvent-free polymer electrolytes (SPEs), gel polymer electrolytes (GPEs), and composite polymer electrolytes (CPEs)), and different flame retardants used to prevent the thermal runaway and combustion of lithium-ion batteries (LIBs). Additionally, various flame tests used for electrolytes in LIBs have been adopted. Aside from a detailed description of the electrolytes consumed in LIBs. Last section in this work discusses hydrogen as a source of fuel cell operation and its practical application as a global trend that supports green chemistry.

This paper shows use of starch-based carbon (CSC) and graphene as the anode electrode for lithium-ion cell. To describe electrochemical stability of the half-cell system and kinetic parameters of charging process in different temperatures, electrochemical impedance spectroscopy (EIS) measurement was adopted. It has been shown that smaller resistances are observed for CSC. Additionally, Bode plots show high electrochemical stability at higher temperatures. The activation energy for the SEI (solid–electrolyte interface) layer, charge transfer, and electrolyte were in the ranges of 24.06–25.33, 68.18–118.55, and 13.84–15.22 kJ mol−1, respectively. Moreover, the activation energy of most processes is smaller for CSC, which means that this electrode could serve as an eco-friendly biodegradable lithium-ion cell element.

Over the past decades, the application of new hybrid materials in energy storage systems has seen significant development. The efforts have been made to improve electrochemical performance, cyclic stability, and cell life. To achieve this, attempts have been made to modify existing electrode materials. This was achieved by using nano-scale materials. A reduction of size enabled an obtainment of changes of conductivity, efficient energy storage and/or conversion (better kinetics), emergence of superparamagnetism, and the enhancement of optical properties, resulting in better electrochemical performance. The design of hybrid heterostructures enabled taking full advantage of each component, synergistic effect, and interaction between components, resulting in better cycle stability and conductivity. Nowadays, nanocomposite has ended up one of the foremost prevalent materials with potential applications in batteries, flexible cells, fuel cells, photovoltaic cells, and photocatalysis. The main goal of this review is to highlight a new progress of different hybrid materials, nanocomposites (also polymeric) used in lithium-ion (LIBs) and sodium-ion (NIBs) cells, solar cells, supercapacitors, and fuel cells and their electrochemical performance.

Hydrothermal crystallization was used to synthesize an advanced hybrid system containing titania and molybdenum disulfide (with a TiO2:MoS2 molar ratio of 1:1). The way in which the conditions of hydrothermal treatment (180 and 200 &deg, C) and thermal treatment (500 &deg, C) affect the physicochemical properties of the products was determined. A physicochemical analysis of the fabricated materials included the determination of the microstructure and morphology (scanning and transmission electron microscopy&mdash, SEM and TEM), crystalline structure (X-ray diffraction method&mdash, XRD), chemical surface composition (energy dispersive X-ray spectroscopy&mdash, EDS) and parameters of the porous structure (low-temperature N2 sorption), as well as the chemical surface concentration (X-ray photoelectron spectroscop&mdash, XPS). It is well known that lithium-ion batteries (LIBs) represent a renewable energy source and a type of energy storage device. The increased demand for energy means that new materials with higher energy and power densities continue to be the subject of investigation. The objective of this research was to obtain a new electrode (anode) component characterized by high work efficiency and good electrochemical properties. The synthesized TiO2-MoS2 material exhibited much better electrochemical stability than pure MoS2 (commercial), but with a specific capacity ca. 630 mAh/g at a current density of 100 mA/g.

This work determines the effect of the addition of various amounts of vanadium oxide on the work of a cell built from a hybrid VxOy-TiO2-rGO system in a lithium-ion cell. Moreover, a new method based on solvothermal chemistry is proposed for the creation of a new type of composite material combining reduced graphene, vanadium oxide and crystalline anatase. The satisfactory electrochemical properties of VxOy-TiO2-rGO hybrids can be attributed to the perfect matching of the morphology and structure of VxOy-TiO2 and rGO. In addition, it is also responsible for the partial transfer of electrons from rGO to VxOy-TiO2, which increases the synergistic interaction of the VxOy-TiO2-rGO hybrid to the reversible storage of lithium. In addition a full cell was created LiFePO4/VxOy-TiO2-rGO. The cell showed good cyclability while providing a capacity of 120 mAh g&minus, 1.

A novel TiO2-SiO2/Bi2O3 oxide material (TSB) was prepared for a first time via the sol-gel method. The synthesis was performed using titanium(IV) isopropoxide, tetraethoxysilane and bismuth nitrate pentahydrate as oxide precursors, ammonia as hydrolysis promoter and propan-2-ol as solvent. The properties of the synthesized material were comprehensively analyzed, including dispersion characteristics, morphology, crystalline structure, chemical composition and porous structure parameters. Additionally, to confirm the chemical structure and the presence of characteristic surface groups, Fourier transform infrared spectroscopy was applied. The electrochemical properties of a TiO2-SiO2/Bi2O3 anode, operating in 1M LiPF6 in EC/DMC (ethylene carbonate/dimethyl carbonate), were studied. The key point of the investigation was to demonstrate a potential application of TSB material in a Li-ion cell. Electrodes were analyzed with the use of cyclic voltammetry (CV), galvanostatic charging/discharging tests, and scanning electron microscopical (SEM) evaluations were performed. SEM images of both electrodes after charging/discharging processes showed that they to be covered with a film (electrochemical SEI formation). The reversible capacity of the TiO2-SiO2/Bi2O3 anode after 20 cycles at a low current rate was close to the theoretical value of 250 mAh g−1. However, at increasing current rates it decreased to ca. 200 mAh g−1. The reversibility of the process was close to 95%. Moreover after 100 cycle at 50 mA g−1 the value was 198 mAh g−1.

The commercial electrode Li4Ti5O12 was modified with SiO2 and TiO2-SiO2. All samples were characterized by scanning electron microscope (SEM), particle size distribution (PSD), porous structure parameters (low-temperature N2 sorption), galvanostatic charge–discharge test, cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). Appropriate amount of TiO2-SiO2 and SiO2 could effectively reduce the electrochemical polarization of Li4Ti5O12 and enhance electrochemical reaction kinetics of Li+ insertion/deinsertion. Moreover, Li4Ti5O12/TiO2-SiO2 provides a high rate capacity of 165 mAh g−1 at the high current density of 0.5 C. To investigate cycle stability of the electrode materials at high current density, the measurements were directly carried out at 3 C. SEM images of the LTO/TiO2-SiO2, LTO, and LTO/SiO2 particles after galvanostatic charging/discharging show that they were coated by a uniform layer (the SEI layer).

The main aim of this research is the evaluation of the diffusion coefficient, ionic conductivity of carbon-based anode materials (graphene and carbon from corn starch (CSC)) at different temperature conditions. This serves to appraise those materials for the more demanding cell conditions and reducing the explosiveness of the battery. Additionally, the very innovative part of the research is the designation of the kinetic and thermodynamic parameters for two different models for lithium ions diffusion during the charge of the half-cell. The activation energy of the diffusion process has the values in the range of 37.37–39.95 kJ mol−1 for CSC compared to graphene (43.80–46.38 kJ mol−1). Additionally, the lithiation process is thermodynamically endothermic and forced. The use of the carbon based on the corn starch as the anode material is connected with the “Green Chemistry” aspect, which improves the availability of materials, biodegradability and cost of the system. All investigations were carried out using the Electrochemical Impedance Spectroscopy (EIS), what also shows the possibilities of this technique to evaluate the important parameters during the work of the cell and optimization, and the thermodynamic and kinetic response of the system against different conditions.

Starch is a modern and prospective biodegradable material, which could improve lithium-ion batteries by making them safer and thus increasing the energy density and capacity of the cells. The main aim of this study was to research the influence of the physical and chemical properties of different botanical origin starches on their electrochemical properties. The investigation was carried out by examining the colloid stability of starches in water solution at room temperature, and the size of particles, which gave really good stability results. Moreover, the vibrations and the functional groups structure were described by Fourier Transform Infrared Spectroscopy (FTIR). The surface properties were characterized by determining the specific surface area, pore diameter and volume diameter. The structures of the granules were determined by scanning electron microscope (SEM) measurement. The results of the electrochemical investigations showed good cyclic reversibility and stability. The research was aimed at improving and modifying current lithium-ion cells using biodegradable material as an active anode material, which is connected with the currently well-known "Green Chemistry".

A composite of aminosilane-grafted TiO2 (TA) and graphene oxide (GO) was prepared via a hydrothermal process. The TiO2/graphene oxide-based (TA/GO) anode was investigated in an ionic liquid electrolyte (0.7 M lithium bis(trifluoromethanesulfonyl)imide (LiNTf2)) in ionic liquid (N-methyl-N-propylpyrrolidinium bis(trifluoromethanesulfonyl)imide (MPPyrNTf2)) at room temperature and in sulfolane (1 M lithium hexafluorophosphate (LiPF6) in tetramethylene sulfolane (TMS)). Scanning and transmission electron microscopy (SEM and TEM) observations of the anode materials suggested that the electrochemical intercalation/deintercalation process in the ionic liquid electrolyte with vinylene carbonate (VC) leads to small changes on the surface of TA/GO particles. The addition of VC to the electrolyte (0.7 M LiNTf2 in MPPyrNTf2 + 10 wt.% VC) considerably increases the anode capacity. Electrodes were tested at different current regimes in the range 5–50 mA g−1. The capacity of the anode, working at a low current regime of 5 mA g−1, was ca. 245 mA g−1, while a current of 50 mA g−1 resulted in a capacity of 170 mA g−1. The decrease in anode capacity with increasing current rate was interpreted as the result of kinetic limits of electrode operation. A much lower capacity was observed for the system TA/GO│1 M LiPF6 in TMS + 10 wt.% VC│Li.

This paper demonstrates a new modified precipitated silica (SiO2) and PAN/TMS – poly(acrylonitrile)/sulfolane – polymeric matrix as a composite gel polymer electrolyte for a lithium-ion battery. Synthetic inorganic material was obtained by the emulsion method with cyclohexane as the organic phase and sodium silicate solution as a precipitating agent. The characterisation included determination of dispersion and morphology of the systems (particle size distribution, scanning electron microscope images), as well as impedance analysis, cyclic voltammetry and charging/discharging. It was found that the silica fillers were homogeneously dispersed in the polymeric matrix, while conductivity and electrochemical stability of porous polymer electrolytes were enhanced. Applicability of the prepared gel electrolytes for the Li-ion technology was estimated on the basis of specific conductivity measurements. Basic electrochemical properties of the composite gel polymer electrolyte was also presented based on PVdF-HFP/TMS/LiPF6/SiO2. A significantly poorer capacity and conductivity were observed. The Li|GPE|LiMn2O4 cell using modified SiO2 in the composite gel polymer electrolyte PAN/TMS shows a high discharge capacity.

This paper describes the synthesis and physicochemical properties of a new type of titania/graphene oxide (TA/GO) composite. Titania powder was synthesized via the sol–gel method, and its surface was functionalized with N-2-(aminoethyl)-3-aminopropyltrimethoxysilane (AAPTS) to increase its adhesion to graphene oxide. Transmission electron microscopy (TEM), non-invasive back scattering (NIBS), porous structure parameters (low-temperature nitrogen sorption), degree of modification of titania and TA/GO determined by Fourier-transform infrared spectroscopy (FT-IR), impedance analysis, charging/discharging and cyclic voltammetry were carried out. At a current density of 50 mA g−1, the good cyclability exhibited by the TA/GO anode can be readily retained at 370 mAh g−1 after 50 cycles, which is outstanding among the TiO2 composites reported in the literature.

The paper describes the investigations of the physicochemical properties of biocoal, a solid fuel obtained following the carbonization of rice starch. The production of biocoal (carbonization) was completed at the temperature of 600 &deg, C in the nitrogen atmosphere. As a result of the carbonization, amorphous carbon with high monodispersity was obtained, devoided of oxygen elements and was a very well developed BET specific surface&mdash, 360 m2 g&minus, 1. The investigations of the technical parameters have confirmed a very high concentration of energy. The calorific value of 53.21 MJ kg&minus, 1 and the combustion heat of 54.92 MJ kg&minus, 1 are significantly higher than those of starch before carbonization (18.72 MJ kg&minus, 1 and 19.43 MJ kg&minus, 1, respectively) and these values for typical biomass fuels. These values are also greater than those of hard coal. Other advantageous features of the obtained fuel are low ash (0.84%) and moisture content. These features predispose this fuel for the application as an alternative to conventional fuels.

TiO2-MoO3 composite systems were successfully prepared using a template-assisted microwave method at molar ratios TiO2:MoO3 = 8:2, 5:5 and 2:8. The synthesized material systems were comprehensively characterized, in terms of their crystalline structure (XRD and Raman spectroscopy), morphology (SEM, TEM and HRTEM analysis) and parameters of the porous structure (low-temperature N2 sorption). The materials exhibited highly crystalline phases: anatase and hexagonal molybdenum trioxide. Moreover, TEM analysis revealed hexagonal prism particles of MoO3 and nanocrystalline particles of TiO2. The proposed template-assisted microwave synthesis enabled the incorporation of TiO2 particles on the surface of hexagonal particles of MoO3, which resulted in a stable junction between titania and molybdenum trioxide. The values of BET surface area were 57, 29 and 11 m2/g for samples obtained at molar ratios TiO2:MoO3 = 8:2, 5:5 and 2:8 respectively. In electrochemical applications, titanium dioxide plays a crucial role as an intercalation intensifier, in which MoO3 is responsible for current conduction. Taking account of the potential electrochemical applications, the best system was obtained at the molar ratio TiO2:MoO3 = 5:5. The anode could maintain a capacity of 400 mAh/g at current densities in the range 100&ndash, 1000 mA/g at potential values ranging from 1.00 to 3.30 V vs. Li/Li+. X-ray photoelectron spectroscopy (XPS) confirmed the effective intercalation of lithium ions into the TiO2-MoO3 composite materials.

The main aim of this study is to estimate the kinetic and thermodynamic parameters of thermal decomposition of starches by the Coats&ndash, Redfern method. This procedure is a commonly used thermogravimetric analysis/difference thermal gravimetry/differental thermal analysis (TG/DTG-DTA) kinetic method for single rate form. The study also shows a proposed method for reactive hydroxyl groups content on the starch surface determination, and values were in range of 960.21&ndash, 1078.76 mg OH per 1 g of starch. Thermal processing revealed the thermophysical properties of biomass for the kinetics of decomposition estimation. Activation energies reached the values in range of approximately 66.5&ndash, 167 kJ&middot, mol&minus, 1. This research also enables the determination of the temperature conditions required for becoming the desired form of material. Therefore, it is necessary to achieve the requested compact porous structure in an activation process, because in the native state, the polymer exhibits limited applications as a result of thermal decomposition, low shear stress, retrogradation, and syneresis, hence the low solubility in organic solvents. Thermodynamic parameters and reactive hydroxyl groups in this article review are innovative and have not yet been found in the literature.

A new type of ceramic filler (TiO2-SiO2) was used in composite gel polymer electrolytes for application in lithium-ion batteries (LiMn2O4|Li). TiO2-SiO2 ceramic powders were obtained by co-precipitation from solutions of titanium sulphate and sodium silicate. The resulting submicron-size powders were used as fillers in composite gel polymer electrolytes for Li-ion batteries based on polyacrylonitrile (PAN) membranes and sulpholane (TMS). The composite gel polymer electrolytes (PE) were analysed structurally and electrochemically, demonstrating favourable properties in terms of electrolyte uptake and electrochemical characteristics in Li-ion cells. The surface morphology of the PE was studied using scanning electron microscopy (SEM). It was found to be a stable, porous and flexible polymer electrolyte with an ionic conductivity of 9.8 × 10−4 S cm−1 at 25 °C. The performance of the LiMn2O4|PE3|Li cell was tested using electrochemical impedance spectroscopy (EIS) and galvanostatic charge/discharge. The LiMn2O4 cathode exhibited good cyclability and coulombic efficiency (ca. 145 mAh g−1 after 50 cycles) when used together with 1 M LiPF6 in PAN/TMS/TiO2-SiO2+ 8 wt.% VC.

Kraft lignin (KL) was activated using selected ionic liquids (ILs). The activated form of the biopolymer, due to the presence of carbonyl groups, can be used in electrochemical tests. To increase the application potential of the system in electrochemistry, activated lignin forms were combined with manganese dioxide, and the most important physicochemical and morphological-microstructural properties of the novel, functional hybrid systems were determined using Fourier transform infrared spectroscopy (FTIR), elemental analysis (EA), scanning electron microscopy (SEM), zeta potential analysis, thermal stability (TGA/DTG) and porous structure analysis. An investigation was also made of the practical application of the hybrid materials in the production of lithium ion batteries. The capacity of the anode (MnO2/activated lignin), working at a low current regime of 50 mA·g−1, was ca. 610 mAh·g−1, while a current of 1000 mA·g−1 resulted in a capacity of 570 mAh·g−1. Superior cyclic stability and rate capability indicate that this may be a promising electrode material for use in high-performance lithium ion batteries.

Electrochemical properties of the graphite anode and the LiFePO4 cathode, working together with the 1 M LiPF6 in TMS (sulpholane) at 90 °C have been studied. The general aim of the investigation was to demonstrate a potential application for a Li-ion cell working in the cooling system of a car heat engine (90 °C). Electrodes were characterized with the use of electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM) as well as galvanostatic charging/discharging tests. SEM images of both electrodes after charging/discharging processes were covered with a film (electrochemical SEI formation). The charge transfer resistance at 90 °C, Rct, of the C6Li|Li+ anode and the LiFePO4 cathode was 24 Ω and 110 Ω, respectively. Reversible capacity of the LiC6 anode after 10–20 cycles, at a low current rate was close to the theoretical value of 370 mAh g−1 however an increasing current rate decreased to ca. 200 mAh g−1 (for 1C). The reversibility of the process was close to 95%. The capacity of the LiFePO4 cathode was ca. 150 mAh g−1, almost independent of the current rate and close to the theoretical value of 170 mAh g−1.

This paper describes the synthesis and properties of a new type of ceramic fillers for composite polymer gel electrolytes. Hybrid TiO 2 -SiO 2 ceramic powders have been obtained by co-precipitation from titanium(IV) sulfate solution using sodium silicate as the precipitating agent. The resulting submicron-size powders have been applied as fillers for composite polymer gel electrolytes for Li-ion batteries based on polyacrylonitrile (PAN) membranes. The powders and gel electrolytes have been examined structurally and electrochemically, showing favorable properties in terms of electrolyte uptake and electrochemical characteristics in Li-ion cells.

The aim of the present work was to perform a preliminary study of the physicochemical properties of hybrid organic–inorganic gel electrolytes for Li-ion batteries based on the PAN/TMS - poly(acrylonitrile)/sulfolane - polymeric matrix and surface-modified precipitated silicas. Modifications were done by means of the so-called dry method using silane U-511 3-methacryloxypropyltrimetoxysilane. Scanning electron microscopy (SEM), noninvasive back scattering method (NIBS), specific surface area (BET), the degree of modification of the silica fillers—Fourier-transform infrared spectroscopy (FT-IR), impedance analysis, and charging/discharging were carried out. It is found that the silica fillers were homogeneously dispersed in the polymeric matrix, which enhanced conductivity and electrochemical stability of porous polymer electrolytes. Applicability of the prepared gel electrolytes for the Li-ion technology was estimated on the basis of specific conductivity measurements. It was shown that modification of the silica surface by the silane causes an increase in the gel-specific conductivity by about 2 orders of magnitude as compared to gel with unmodified silica.

Electrochemical properties of LiNiO2|Li and LiNiO2|graphite cells were analysed in ionic liquid electrolyte [Li+][MePrPyrr+][NTf2-] (based on N-methyl-N-propylpyrrolidinium bis(trifluoromethanesulphonyl)imide, [MePrPyrr+][NTf2-]) using impedance spectroscopy and galvanostatic techniques. The ionic liquid is incapable of protective solid electrolyte interface (SEI) formation on metallic lithium or lithiated graphite. However, after addition of VC, the protective coating is formed, facilitating a proper work of the Li-ion cell. Scanning electron microscopy images of pristine electrodes and those taken after electrochemical cycling showed changes which may be interpreted as a result of SEI formation. The charging/discharging capacity of the LiNiO2 cathode is between 195 and 170 mAh g−1, depending on the rate. The charging/discharging efficiency of the graphite anode drops after 50 cycles from an initial value of ca. 360 mAh g−1 to stabilise at 340 mAh g−1. The replacement of a classical electrolyte in molecular liquids (cyclic carbonates) with an electrolyte based on the MePrPyrrNTf2 ionic liquid highly increases in the cathode/electrolyte non-flammability.

Two types of silica: precipitated (P, prepared in non-polar media, a new type, submicrometer sized) and fumed (F, nanosized), both unmodified and surface modified are investigated as functional fillers for potential applications in nanocomposites with poly(2-hydroxyethyl methacrylate) matrix. Special attention is paid to the kinetics of composite formation in an in situ photopolymerization process. Silica-containing formulations polymerize faster; this effect is much stronger for silica P having much larger particle size than silica F. Surface treatment leads to further acceleration of the polymerization in case of silica P but to retardation in case of silica F; the effect of modification of the filler surface on properties of composites is different for each of the silicas. The obtained results are discussed in terms of effects of curvature of silica particles, surface properties, solvation cell, interphase region, viscosity changes, and morphology of the resulting composites. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 3472–3487