Discharge Capacity Values Research Articles

Evaluating a Fe-Based Metallic Glass Powder as a Novel Negative Electrode Material for Applications in Ni-MH Batteries

Metallic glasses (MGs) are a type of multicomponent non-crystalline metallic alloys obtained by rapid cooling, which possess several physical, mechanical, and chemical advantages against their crystalline counterparts. In this work, an Fe-based MG is explored as a hydrogen storage material, especially, due to the evidence in previous studies about the capability of some amorphous metals to store hydrogen. The evaluation of an Fe-based MG as a novel negative electrode material for nickel/metal hydride (Ni-MH) batteries was carried out through cyclic voltammetry and galvanostatic charge–discharge tests. A conventional LaNi5 electrode was also evaluated for comparative purposes. The electrochemical results obtained by cyclic voltammetry showed the formation of three peaks, which are associated with the formation of Fe oxides/oxyhydroxides and hydroxides. Cycling charge/discharge tests revealed activation of the MG electrode. The highest discharge capacity value was 173.88 mAh/g, but a decay in its capacity was observed after 25 cycles, contrary to the LaNi5, which presents an increment of the discharge capacity for all the current density values evaluated, reached its value maximum at 183 mAh/g. Characterization analyses performed by X-ray diffraction, Scanning Electron Microscopy and Raman Spectroscopy revealed the presence of corrosion products and porosity on the surface of the Fe-based MG electrodes. Overall, the Fe-based MG composition is potentially able to work as a negative electrode material, but degradation and little information about storage mechanisms means that it requires further investigation.

Exploring titanium niobium oxides recovered from columbotantalite mineral as lithium-ion batteries electrodes

Titanium niobium oxides (TNO) are chemically recovered from a mineral composed of cassiterite, columbotantalite, rutile and wollastonite. The process involves a series of steps, including pyrometallurgical processes, leaching, and liquid-liquid extraction. It takes advantage of the naturally occurring Ti in the extracted mineral, avoiding the separation of Ti and Nb to directly obtain the valuable Ti–Nb–O compounds. Two compositions can be obtained (Ti2Nb10O29 or TiNb2O7, named TNO-cal and TNO-black, respectively) depending on the thermal treatment after the chemical separation from the original mineral. These compounds have been characterized to describe their composition, morphology and crystallographic properties. The recovered material, without any further purification or functionalization, has been studied as anodes in Lithium-ion batteries (LIBs). Different electrochemical behavior has been observed for voltage ranges of 1–3 V and 0.01–3 V, being the second range which gives best results. In the 1–3V range, TNO-black exhibits a reversible capacity of up to 101.4 mA h g−1 at 1C and maintains 97 % capacity retention after 200 cycles, this is mainly due to Li + insertion/de-insertion processes. Additionally, when expanding the voltage range down to 0.01V, TNO-black displays a specific capacity of approximately 139.1 mA h g−1 after 200 cycles at 1C, whereas TNO-cal reaches a specific capacity of 169 mA h g−1. Extended cycling experiments at a 1C rate for both electrodes reveal that after 200 cycles samples deliver efficiencies relative to the maximum discharge capacity values of 83.4 % (TNO-cal) and 64.4 % (TNO-black), with mean coulombic efficiencies of 97.5 %. These results demonstrate that the recovered materials can effectively function as anodes for LIBs, offering promising application potential, despite the presence of residual silica from the mining process.

Enhanced performance of solid polymer electrolytes combining poly(vinylidene fluoride-co-hexafluoropropylene), metal-organic framework and ionic liquid for advanced solid state lithium-ion batteries

The search for sustainable and high-performance materials for lithium-ion batteries is leading to significant advances in solid polymer electrolyte (SPE) technology. However, the current drawbacks of this approach prove the need for further research and development in the field. Herein, novel ternary solid polymer electrolytes have been developed using varying loads of MOF-808 metal-organic framework and [BMIM][SCN] ionic liquid (IL) incorporated in a poly(vinylidene fluoride-co-hexafluoropropylene) matrix. The solid polymer electrolytes were evaluated at morphological, structural, thermal, mechanical and electrochemical levels, and their performance in cycling battery testing was assessed. The results showed a homogeneous structure throughout all the samples and a good dispersion of the distinct components. The polymer polar phase and degree of crystallinity of the samples are increased with increasing IL content, and the thermal and mechanical properties are appropriate for battery application. The ionic conductivity of the samples reaches maximum values of 4.68 × 10−5 S‧cm−1 at room temperature, lithium transference numbers up to 0.65, and high electrochemical stability, making them well-suited for battery applications. The assembled stability after 50 cycles at C/10 with a discharge capacity value of 150 mAh‧g−1 at room temperature was tested/derived. The obtained results show the potential of this system for high performance room temperature solid polymer electrolytes.

Can the calcination products of the mixture containing TiO2 and CuCl be utilized as anode materials of lithium ions batteries (LIBs)？

For the first time, it is discovered that the calcination products of the mixture containing titanium dioxide (TiO2) and cuprous chloride (CuCl) were a novel kind of anode materials of LIBs. Herein, a mixture containing TiO2 and CuCl with a Ti/Cu mole ratio of 2:1 was calcined at different temperatures in air to harvest the samples. The samples sintered at 350°C, 400°C and 450°C were respectively classified as sample a, b and c. As analyzed, TiO2, CuO and CuCl2 were the principal components of all resultant samples. Interestingly, as compared to the pure TiO2, all prepared samples, especially sample b, delivered a markedly enhanced electrochemical property. For instance, the initial DC (discharge capacity) of sample b at 0.1 A g−1 was 487 mAh g−1, being much better than that of sample a, c and the pure TiO2 (sample o). Impressively, the DC value of sample b was around 101 mAh g−1 at 1.0 A g−1 after 100 cycles, which, respectively, was about 1.5, 2.0 and 5.3 times that of sample a (66 mAh g−1), c (49 mAh g−1) and o (19 mAh g−1). After a thorough investigation, the reduced Rct and the evidently increased DLi+ were considered as the main causes providing all samples, especially sample b, a satisfied electrochemical performance. To summarize, the electrochemical properties of all as-produced samples were better than that of the pure TiO2. That is, a groundbreaking concept, that using a calcination product containing TiO2, CuO and CuCl2 rather than a pure substance as the anode materials of LIBs, was developed here.

Ternary composites of poly(vinylidene fluoride-co-hexafluoropropylene) with silver nanowires and titanium dioxide nanoparticles as separator membranes for lithium-ion batteries

In the realm of polymer composites, there is growing interest in the use of more than one filler for achieving multifunctional properties. In this work, a composite separator membrane has been developed for lithium-ion battery application, by incorporating conductive silver nanowires (AgNWs) and titanium dioxide (TiO2) nanoparticles into a poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) polymer matrix. The composite membranes were manufactured by solvent casting and thermally induced phase separation, with total filler content varying up to 10 wt%. The ternary composites composites present improved mechanical characteristics, ionic conductivity and lithium transfer number compared to the neat polymer matrix. On the other hand, the filler type and content within the composite has little bearing on the morphology, polymer phase, or thermal stability. Once applied as a separator in lithium-ion batteries, the highest discharge capacity value was obtained for the 5 wt% AgNWs/5 wt% TiO2/PVDF-HFP membrane at different C-rates, benefiting from the synergetic effect from both fillers. This work demonstrates that higher battery performance can be achieved for next-generation lithium-ion batteries by using separator membranes based on ternary composites.

Study Of Various Types Of Pvd And Ph.D. Joints On Vertical Drainage Performance

An important factor for increasing the effectiveness of the PVD (Prefabricated Vertical Drains) is the value of sufficient discharge capacity so that the PVD can work optimally. The use of PVD is usually accompanied by the use of PHD (Prefabricated Horizontal Drains) as horizontal drainage and combined with preloading. In the field, the connection is made by winding the PVD to the PHD and then tying it with cable ties. The connection system can cause deformation at the top of the PVD thereby reducing the effectiveness of the PVD discharge capacity. This study aims to find the optimal PVD-PHD connection system for the discharge capacity which is affected by confinement pressure, overburden pressure, and hydraulic gradient with a PVD-PHD connection system discharge capacity tester. The test specimens used were PVD (5mm thick; 100mm wide) and Ph.D. (20 mm thick; wide: 100 mm, 200mm, and 300mm). 4 types of connection systems have been tried, namely connections A1 and A2 where the PHD is connected in a horizontal position, and connections B1 and B2 where the PHD is connected in a vertical position. Of the four connection systems B1, the connection system has the largest discharge capacity value and a significant increase in PHD width from 100 mm to 300 mm with an increase of 7.694% at 50 kPa overburden pressure and 1.0 hydraulic gradient the highest compared to other connection types

MgV3O8 incorporated carbon nanofibers as anode material for high-performance lithium-ion batteries

The rich redox chemistry of vanadate-based materials makes them a potential anode for the fabrication of advanced lithium-ion batteries (LiBs). However, poor electrical conductivity as well as volume variation of vanadate-based anode materials hinders practical applications. Herein, magnesium vanadate (MgV3O8) incorporated carbon nanofibers (CNFs) (MgVO@CNFs) composites were prepared via a simple and scalable electrospinning technique, followed by pyrolysis. The synergistic effect of MgVO and CNFs effectively offers a good conductive path and excellent integrity between the active particles with highly porous network. As an anode for LiBs, the MgVO@CNFs composite electrode exhibited good discharge capacity values of 457 mA h g−1 (over 300 cycles) and 245 mA h g−1 (over 500 cycles) at 0.1 and 0.5 A g−1, respectively and revealed excellent rate performance. The charge storage mechanism of MgVO@CNFs is contributed by both capacitive and diffusion-controlled behaviors. Consequently, this novel preparation process of the MgVO@CNFs may provide a new idea for the fabrication of different kinds of nanostructures for LiB applications.

Selenium incorporated sodium vanadate nanobelts as high-performance electrode material for long-lasting aqueous zinc-ion batteries and supercapacitors

Aqueous zinc-ion batteries (AZIBs) have received growing attention for comprehensive energy storage owing to their affordability and high safety. Still, cathode materials that usually exhibit low capacity or poor cycling performance have hindered the practical application of AZIBs. Herein, the selenium-incorporated sodium vanadate (Na2V6O16) (NVO@Se) nanobelts (NBs) were synthesized via a facile hydrothermal method, followed by calcination under N2 flow. As a cathode for AZIBs, the NVO@Se NBs electrode delivered a high discharge capacity value of 329.15 mA h g−1 at 2 A g−1 with ∼ 99 % coulombic efficiency and excellent rate capability (284.89 and 200.21 mA h g−1 at 4 and 5 A g−1, respectively). Mechanistic analyses of the intercalation reaction in the NVO@Se NBs after cycling using ex-situ X-ray diffraction, field-emission scanning electron microscopy, and X-ray photoelectron spectroscopy techniques revealed their good structural stability and electrochemical reversibility. Developing interactive properties, the NVO@Se NBs material was also studied as a battery-type electrode for hybrid supercapacitors (HSCs). By sandwiching the NVO@Se NBs and activated carbon, the fabricated HSC exhibited good power and energy density values, along with its verification for practical applications. From all the electrochemical characteristic results, the NVO@Se NBs material has good aspects for AZIBs and HSCs, which makes new prospects for the advancement of materials in energy storage applications.

Solid polymer electrolytes based on a high dielectric polymer and ionic liquids for lithium batteries

Solid-state batteries were produced using new solid polymer electrolytes (SPEs) based on the high dielectric constant polymer poly(vinylidene fluoride-trifluoroethylene-chlorofluoroethylene), P(VDF-TrFE-CFE) and 40 wt% of different ionic liquids (IL) sharing the same bis(trifluoromethylsulfonyl)imide [TFSI] anion and different cations. The morphological, thermal, mechanical and electrochemical properties of the SPEs were investigated, as a function of the interaction between IL and polymer matrix. The addition of IL increased the amorphous phase of the polymer with respect to the neat polymer, leading to room temperature ionic conductivity values between 2.3 × 10−5 and 1.4 × 10−4 S cm−1, depending on the specific IL. Further, the highest lithium transference number of 0.71 was obtained for the [PMPyrr][TFSI] sample. Li/LiFePO4 half batteries using these SPEs show excellent and stable battery performance at room temperature at different C-rates. The highest discharge capacity value is achieved for the [PMPyrr][TFSI] sample, reaching 137 mAh.g−1 and 117 mAh.g−1 at C/10 and C/2 rates, respectively, with high coulombic efficiency (∼100%) and low capacity fade after 100 cycles. The use of P(VDF-TrFE-CFE) allows the development of room temperature solid-state lithium-ion batteries and the improved results are associated to the high polymer dielectric constant which facilitates IL ions dissociation, improving SPE ionic mobility.

Grafit Matris Kompozit Faz Dönüşüm Sıcaklığının Kare Dalga Yük Altındaki Küçük Ölçekli Bir Li-iyon Batarya Paketi Performansına Etkisi

An experimental study is performed to illustrate the effect of the melting temperature of graphite matrix composite with phase change materials on the performance characteristics of a small-scale li-ion package (3s2p) under dynamic/square wave load. Paraffin (RT35 and RT42) is used as a PCM. Graphite matrix is manufactured with 75 g l-1 bulk density. The battery package is performed for three different configurations: free-air cooling case (reference case), and graphite matrix composites with RT35 and RT42. The experimental outputs present that graphite matrix composite has considerable potential for thermal management of the Li-ion pack. Safe operating time, discharge and energy capacity values are increased by 140%, 141% and 102% with the graphite composite with RT35 in the comparison reference case, respectively. It is observed that the melting temperature of PCM of graphite composite is of critical importance to the performance of the battery pack. For the graphite composite with RT35, operating time, discharge capacity and energy capacity values are enhanced by 6.2 %, 7 % and 10 % compared to the RT42 case, respectively.

Enhancing electrochemical properties of commercial lithium titanate using cuprous chloride nanoparticle-modified copper foil current collectors

For the first time, CuCl nanoparticles were fabricated at ambient temperature onto the surface of a copper (Cu) foil current collector through using an immersing approach, in which the immersing solution only contained 0.6 M CuSO4 and a very small amount of hexadecyl trimethyl ammonium chloride (HTAC). For simplicity, all as-prepared CuCl nanoparticles modified copper foils were labeled as CuCl/Cu. The specimens of CuCl/Cu prepared in the presence of 4 mM, 8 mM and 12 mM HTAC were designated as specimen a, b and c, respectively. The lithium titanate (Li4Ti5O12, LTO) electrodes assembled using the as-prepared CuCl/Cu exhibited an outstanding electrochemical performance as compared to the conventional LTO electrode manufactured using the commercial bare copper foil. Such as, the initial discharge capacity (DC) value of the LTO electrode assembled using specimen b at 0.2 C was measured to be 216 mAh g−1, which was about 1.3 times that of the conventional LTO electrode (165 mAh g−1). More importantly, at 10 C after 100 cycles, the DC value of the LTO electrode assembled using specimen b was retained to be as high as 143 mAh g−1, being about 3.1 times higher than that of the conventional LTO electrode (46 mAh g−1). A room temperature immersing approach for preparing CuCl nanoparticles and a novel method to significantly improve the electrochemical behavior of the conventional LTO electrode are developed in this work, which is very meaningful not only to the development of CuCl related material science but also to the further progress of LTO based lithium ion batteries (LIBs).

Anthraquinone-Quinizarin Copolymer as a Promising Electrode Material for High-Performance Lithium and Potassium Batteries.

The growing demand for cheap, safe, recyclable, and environmentally friendly batteries highlights the importance of the development of organic electrode materials. Here, we present a novel redox-active polymer comprising a polyaniline-type conjugated backbone and quinizarin and anthraquinone units. The synthesized polymer was explored as a cathode material for batteries, and it delivered promising performance characteristics in both lithium and potassium cells. Excellent lithiation efficiency enabled high discharge capacity values of >400 mA g-1 in combination with good stability upon charge-discharge cycling. Similarly, the potassium cells with the polymer-based cathodes demonstrated a high discharge capacity of >200 mAh g-1 at 50 mA g-1 and impressive stability: no capacity deterioration was observed for over 3000 cycles at 11 A g-1, which was among the best results reported for K ion battery cathodes to date. The synthetic availability and low projected cost of the designed material paves a way to its practical implementation in scalable and inexpensive organic batteries, which are emerging as a sustainable energy storage technology.

Enhancing the Electrode Gravimetric Capacity of Li1.2Mn0.4Ti0.4O2 Cathode Using Interfacial Carbon Deposition and Carbon Nanotube-Mediated Electrical Percolation.

Mn-based cation-disordered rocksalt oxides (Mn-DRX) are emerging as promising cathode materials for next-generation Li-ion batteries due to their high specific capacities and cobalt- and nickel-free characteristic. However, to reach the usable capacity, solid-state synthesized Mn-DRX materials require activation via postsynthetic ball milling, typically incorporating more than 20 wt % conductive carbon that adversely reduces the electrode-level gravimetric capacity. To address this issue, we first deposit amorphous carbon on the surface of the Li1.2Mn0.4Ti0.4O2 (LMTO) particles to increase the electrical conductivity by 5 orders of magnitude. Although the cathode material gravimetric first charge capacity reaches 180 mAh/g, its highly irreversible behavior leads to a first discharge capacity of 70 mAh/g. Subsequently, to ensure a good electrical percolation network, the LMTO material is ball-milled with a multiwall carbon nanotube (CNT) to obtain a 78.7 wt % LMTO active material loading in the cathode electrode (LMTO-CNT). As a result, a 210 mAh/g cathode electrode gravimetric first charge and 165 mAh/g first discharge capacity values are obtained, compared to the respective capacity values of 222 and 155 mAh/g for the LMTO material ball-milled with 20 wt % SuperP C65 electrode (LMTO-SP). After 50 cycles, LMTO-CNT delivers a 121 mAh/g electrode gravimetric discharge capacity, largely outperforming the value of 44 mAh/g of LMTO-SP. Our study demonstrates that while ball milling is necessary to achieve a significant amount of capacity of LMTO, a careful selection of additives, such as CNT, effectively reduces the required carbon quantity to achieve a higher electrode gravimetric discharge capacity.

High Areal Capacity and Sustainable High Energy in Ferroelectric Doped Holey Graphene/Sulfur Composite Cathode for Lithium-Sulfur Batteries

In this study, we are reporting the impact of the incorporation of ferroelectric nanoparticles (FNPs), such as BaTiO3 (BTO), BiFeO3 (BFO), Bi4NdTi3Fe0.7Ni0.3O15 (BNTFN), and Bi4NdTi3Fe0.5Co0.5O15 (BNTFC), as well as the mass loading of sulfur to fabricated solvent-free sulfur/holey graphene-carbon black/polyvinylidene fluoride (S/FNPs/CBhG/PVDF) composite electrodes to achieve high areal capacity for lithium-sulfur (Li-S) batteries. The dry-press method was adopted to fabricate composite cathodes. The hG, a conductive and lightweight scaffold derived from graphene, served as a matrix to host sulfur and FNPs for the fabrication of solvent-free composites. Raman spectra confirmed the dominant hG framework for all the composites, with strong D, G, and 2D bands. The surface morphology of the fabricated cathode system showed a homogeneous distribution of FNPs throughout the composites, confirmed by the EDAX spectra. The observed Li+ ion diffusion coefficient for the composite cathode started at 2.17 × 10−16 cm2/s (S25(CBhG)65PVDF10) and reached up to the highest value (4.15 × 10−15 cm2/s) for S25BNTFC5(CBhG)60PVDF10. The best discharge capacity values for the S25(CBhG)65PVDF10 and S25BNTFC5(CBhG)60PVDF10 composites started at 1123 mAh/gs and 1509 mAh/gs and dropped to 612 mAh/gs and 572 mAh/gs, respectively, after 100 cycles; similar behavior was exhibited by the other composites that were among the best. These are better values than those previously reported in the literature. The incorporation of ferroelectric nanoparticles in the cathodes of Li-S batteries reduced the rapid formation of polysulfides due to their internal electric fields. The areal capacity for the S25(CBhG)65PVDF10 composites was 4.84 mAh/cm2 with a mass loading of 4.31 mgs/cm2, while that for the S25BNTFC5(CBhG)60PVDF10 composites was 6.74 mAh/cm2 with a mass loading of 4.46 mgs/cm2. It was confirmed that effective FNP incorporation within the S cathode improves the cycling response and stability of cathodes, enabling the high performance of Li-S batteries.

Influence of Solvent Evaporation Temperature on the Performance of Ternary Solid Polymer Electrolytes Based on Poly(vinylidene fluoride-co-hexafluoropropylene) Combining an Ionic Liquid and a Zeolite.

Solid polymer electrolytes (SPEs) will allow improving safety and durability in next-generation solid-state lithium-ion batteries (LIBs). Within the SPE class, ternary composites are a suitable approach as they provide high room-temperature ionic conductivity and excellent cycling and electrochemical stability. In this work, ternary SPEs based on poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) as a polymer host, clinoptilolite (CPT) zeolite, and 1-butyl-3-methylimidazolium thiocyanate ([Bmim][SCN])) ionic liquid (IL) as fillers were produced by solvent evaporation at different temperatures (room temperature, 80, 120, and 160 °C). Solvent evaporation temperature affects the morphology, degree of crystallinity, and mechanical properties of the samples as well as the ionic conductivity and lithium transference number. The highest ionic conductivity (1.2 × 10-4 S·cm-1) and lithium transference number (0.66) have been obtained for the SPE prepared at room temperature and 160 °C, respectively. Charge-discharge battery tests show the highest value of discharge capacity of 149 and 136 mAh·g-1 at C/10 and C/2 rates, respectively, for the SPE prepared at 160 °C. We conclude that the fine control of the solvent evaporation temperature during the preparation of the SPE allows us to optimize solid-state battery performance.

Influence of ionic liquid characteristics on the performance of ternary solid polymer electrolytes with poly(vinylidene fluoride-co-hexafluoropropylene) and zeolite

Solid polymer electrolytes (SPEs) are the necessary step towards solid-state lithium-ion batteries (LIBs). Their function as separator and electrolyte allows to increase the safety of energy storage devices by the elimination of the liquid components. In this work, three-component SPEs based on poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) as host polymer, clinoptilolite zeolite, and different ionic liquids (ILs) (1-ethyl-3-methylimidazolium thiocyanate ([EMIM][SCN]), 1-butyl-3-methylimidazolium thiocyanate ([BMIM][SCN]), 1-ethyl-3-methylimidazolium dicyanamide ([EMIM][NCN2]) and 1-butyl-3-methylimidazolium dicyanamide ([BMIM][NCN2]) were produced and characterized. The influence of the nature of the IL anion and cation on the morphology, degree of crystallinity, mechanical properties, ionic conductivity, and battery cycling performance were studied. It is demonstrated that the [SCN]- anion is the most suitable if SPE applications are envisaged. The ionic conductivity depends on the IL type. At room temperature, a maximum value of 1.3 × 10−5 S cm−1 was obtained for the SPE doped with [BMIM][NCN2]. Regarding battery performance, the best value of discharge capacity was observed for the SPE based on [BMIM][SCN], which for an initial discharge capacity of 135 mAh.g−1 yielded a capacity loss below 30% after 30 cycles at room temperature. Thus, it is concluded that proper selection of the IL (cation chain length and anion size) allows tailoring battery performance of solid-state batteries based on three-component SPEs.

Preparation of Metal-Oxide-Doped Li7P2S8Br0.25I0.75 Solid Electrolytes for All-Solid-State Lithium Batteries.

The all-solid-state lithium battery (ASSB) has received great attention due to its greater safety than the conventional lithium-ion battery (LIB). Sulfide-based inorganic solid electrolytes are an important component to fabricate the ASSB. But to attain a better performance, the ionic conductivity and electrochemical stability of the sulfide-based solid electrolytes need to be improved. In this work, we prepared the metal-oxide-doped/mixed Li7P2S8I0.75Br0.25 lithium superionic conductors by a dry ball-milling process. The high ionic conductivity was achieved by a low-temperature (200 °C) heat-treatment process. The metal-oxide-doped Li7P2S8I0.75Br0.25 solid electrolyte exhibited a higher ionic conductivity value of 7.3 mS cm-1 at room temperature than the bare Li7P2S8I0.75Br0.25 solid electrolyte. The structural characteristics of the prepared solid electrolytes were studied by solid NMR and laser Raman analysis. The electrochemical stability of the prepared solid electrolyte was studied by cyclic voltammetry and DC charge-discharge analysis. The addition of metal oxide increased the electrochemical stability and dry-air stability of the Li7P2S8I0.75Br0.25 solid electrolyte. The Ta2O5-doped Li7P2S8I0.75Br0.25 solid electrolyte was stable even after 300 charge-discharge DC cycles and also 100 h of dry-air exposure. Further, the Ta2O5-doped Li7P2S8I0.75Br0.25 solid electrolyte-based ASSB exhibited a high discharge capacity value of 184 mA h g-1 at 0.1 C rate with 66% initial cycle Coulombic efficiency.

Investigation the effects of chlorine doped graphene oxide as an electrolyte additive for gel type valve regulated lead acid batteries

In this study, chlorine-doped graphene oxide (Cl-GOP) was used as an additive in the fumed silica-based gel electrolyte system of Valve Regulated Lead Acid (VRLA) batteries for the first time in the literature, and the performance of the gel electrolyte was increased. In this context, chlorine-doped graphene oxide produced by electrochemical methods was characterized using spectroscopic and microscopic methods, and then it was added to the fumed silica based gel electrolyte as an additive. The amount of Cl-GOP in the gel electrolyte system was optimized using electrochemical methods and 0.6 % by mass was determined as the most suitable. Then, the stirring rate and agitation time, which are the most important parameters affecting the performance of the gel electrolyte system, were optimized and the optimum values were determined as 500 rpm and 30 min, respectively. Finally, the prepared fumed silica-based electrolyte systems and aqueous electrolyte systems were subjected to charge-discharge tests and the highest discharge capacity value was determined as 42 mAh.cm−2 in the fumed silica-based gel electrolyte system containing Cl-GOP with 20 mA.cm−2 charge-discharge current densities. The results showed that Cl-GOP is an important additive in the fumed silica-based gel component of gel type VRLA batteries.

Exploring the intercalation chemistry and Li ion dynamics in Li4WO5: An anode material for Li-ion batteries

Electrochemical properties, Li ion dynamics and intercalation chemistry in Li4WO5 bulk material is explored in this work. X-ray diffraction and Raman spectra studies confirm the formation of Li4WO5 in orthorhombic structure. Electrochemical charge discharge studies at 0.1 C rate reveal that the discharge and charge capacity values at 2nd cycle is 364 mAh/g 286 mAh/g respectively. After 100 cycles the discharge and charge capacity values are seen to increase to 575 mAh/g and 549 mAh/g respectively with 99% Columbic efficiency. Intercalation chemistry and retention of orthorhombic structure during the electrochemical cycling with small changes in the lattice parameters in Li4WO5 is confirmed from the ex-situ XRD and Raman studies. In-situ XRD measurement during the first cycle confirms the stable structure of Li4WO5 with a small distortion in (531) plane due to the removal and insertion of Li. Irreversible redox peak and the unknown phases from the solid electrolyte interface appeared at 0.7 V during the first discharge process are probed from the addition diffraction peaks appeared in the in-situ XRD pattern. The Li ion diffusion coefficient value is calculated to be 2.96 × 10−14 cm2/s. Electrochemical impedance spectroscopy (EIS) studies showed the reduction in charge transfer resistance with increasing cycle number. Observed intercalation chemistry, high-rate performance and virtuous specific capacity in Li4WO5 indicates that it can be applied as an anode material for high performance LIB’s.

Improved Performance of Silicon Anodes Using Copper Nanoparticles as Additive

Abstract Nanoscale copper has been successfully integrated into a silicon-based anode via a cost-effective, one-step process. The additive was found to improve the overall electrical conductivity and charge/discharge cycling performance of the anode. Analysis of the new material shows that copper particles are homogeneously interspersed into the silicon active layer. The formation of Cu3Si during the annealing step of the fabrication process was also confirmed using X-ray diffraction and is thought to contribute to the structural stability of the anode during cycling. Despite the inclusion of only small quantities of the additive (approximately 3%), anodes with the added copper show significantly higher initial discharge capacity values (957 mAg−1) compared to anodes without copper (309 mAg−1), and they continue to outperform the latter after 100 charge/discharge cycles. Results also show a significant decrease in the resistance of anodes with the additive, a contributing factor in the improvement of the electrochemical performance.