Anodic Half-cell Research Articles

Utilizing a Novel Electrolyte Additive for Improvement of the Solid Electrolyte Interphase on Silicon Anodes of Lithium-Ion Batteries

Graphite is currently the most widely used anode material in lithium-ion batteries due to its layered structure and long cycling stability. However, any lithium-ion batteries built with graphite are inherently limited by graphite’s moderate theoretical capacity of 372mAh/g and subsequent low energy density. A more promising anode material is silicon due to its significantly higher theoretical capacity of 3579mAh/g, creating a much higher energy density. Unfortunately, silicon experiences large volume changes during cycling that causes the pulverization of active materials, thus fracturing the electrode surface and reducing electrical conductivity. The constant morphology changes furthermore damage the formation of a stable solid electrolyte interphase (SEI) on the silicon particles, causing continuous consumption of electrolyte and thickening of the SEI layer. These all contribute to rapid capacity decay and short cycle life. One way to improve the cycling performance of silicon anodes is to include electrolyte additives like fluoroethylene carbonate (FEC) that preferentially reduce on the surface of the anode. These additives enable the ability to develop a more robust and flexible passivation film that can accommodate electrode expansion. In this study, a novel electrolyte additive formulation was used to improve the long-term cycling stability of silicon anode half cells. The resultant SEI layer was characterized using X-ray photoelectron spectroscopy and attenuated total reflectance infrared spectroscopy as well as examined using scanning electron microscopy for morphology changes.

Garnet-Based Composite Cathodes for Polymer-Ceramic Solid-State Li Batteries

Ceramic solid-state Li batteries (SSLBs) with high capacity composite cathodes have a huge potential to outperform conventional Li-ion batteries [1]. Among the most promising ceramic electrolytes is garnet-based Li7La3Zr2O12 (LLZ), which has a wide electrochemical window, stability vs metallic Li, and good Li-ion conductivity at room temperature [1]. However, so far, the electrochemical cycling stability of all ceramic solid-state SSLBs is low [1]. The volume changes in the cathode active materials (CAMs) during cycling can cause cracks at the rigid CAM/ceramic electrolyte interface if the density of the mixed cathode is low. To mitigate the detrimental effects of crack formation, polymer electrolyte can be added to fill the cracks could and ensure a good contact between CAM and ceramic electrolyte. Such a concept is called polymer-ceramic SSLB [2].LLZ-based polymer ceramic SSLBs have already shown good electrochemical properties. Commonly the cells are constructed based on a LLZ separator with a dense and porous side that are manufactured by tape-casting [2, 3]. The tape-casting process is not straight forward as it requires the preparation of a slurry with organic solvents. Furthermore, the grain morphology has a major impact on the final LLZ microstructure. Afterwards, the tape-casted LLZ separator is conventionally sintered and grain growth and loss of volatile elements, such as Li, occurs. The sintered LLZ separator is then infiltrated by CAM solution [3]. After drying the CAM solution the polymer electrolyte is added.In a powder-based process, co-sintering the LLZ and CAM simplifies the manufacturing. Another advantage is that the porous LLZ framework is stabilized by the CAM and allows to reduce the LLZ amount in the porous framework in order to achieve higher CAM loadings. However, the high sintering temperature and long dwell time for the sintering of garnet-based LLZ electrolyte lead to reactions with cathode active materials (CAMs) and hamper the manufacturing of composite cathodesA reduction in sintering temperature and dwell time can be achieved by advanced sintering techniques, such as Field-Assisted-Sintering-Technique/Spark Plasma Sintering (FAST/SPS). FAST/SPS applies rapid Joule heating and mechanical pressure. This shortens the required processing times due to faster heating and an increased sintering rate and reduces the sintering temperatures. By that less grain growth is observed, and the loss of volatile elements is reduced.Recently, we showed, that FAST/SPS can co-sinter LLZ and LiCoO2 (LCO) and allows the preparation of an LLZ/LCO composite cathode in one step. The LLZ/LCO phases are clean and provide a low interface impedance [4]. Another advantage is that the thickness of the composite cathode is easily scalable. However, the obtained density was around 95 % and only closed porosity was observed, that prevents the polymer infiltration.In this work, the FAST/SPS process is adjusted to manufacture phase pure porous LLZ/LCO-composite cathodes in one sintering step. The porosity is easily controllable, without the requirement of pore former by the applied pressure during FAST/SPS. Infiltration of polymer electrolyte into the pores within the composite cathode leads to significantly lowered interfacial impedances. The porous composite cathode can be assembled into a polymer ceramic SSLB by attaching it to an anodic half-cell (separator and anode) to demonstrate the functionality of the presented concept.

Electrodeposition of palladium-dotted nickel nanowire networks as a robust self-supported methanol electrooxidation catalyst

Mass activity and long-term stability are two major issues in current fuel cell catalyst designs. While supported catalysts normally suffer from poor long-term stability but show high mass activity, unsupported catalysts tend to perform better in the first point while showing deficits in the latter one. In this study, a facile synthesis route towards self-supported metallic electrocatalyst nanoarchitectures with both aspects in mind is outlined. This procedure consists of a palladium seeding step of ion track-etched polymer templates followed by a nickel electrodeposition and template dissolution. With this strategy, free-standing nickel nanowire networks which contain palladium nanoparticles only in their outer surface are obtained. These networks are tested in anodic half-cell measurements for demonstrating their capability of oxidising methanol in alkaline electrolytes. The results from the electrochemical experiments show that this new catalyst is more tolerant towards high methanol concentrations (up to {5},hbox{mol},hbox{L}^{-1}) than a commercial carbon supported palladium nanoparticle catalyst and provides a much better long-term stability during potential cycling.Graphical

Li-based all‑carbon dual-ion batteries using graphite recycled from spent Li-ion batteries

Recycling and regeneration of spent Li-ion batteries have become an important research topic for a sustainable future. This is predominantly because of the exponentially increasing production & usage of lithium ion batteries (LIBs) leading to an intense reflux as spent/failed/end-of-life batteries in the near future. Research on recycling/regenerating cathode materials has been a major attraction while ignoring the anode part, the graphite. In the present work, we demonstrate the possibility of recycling graphite recovered from spent Li-ion batteries for Li-ion based all‑carbon dual-ion battery (ACDIB) application. Graphite electrodes recovered from failed commercial batteries were thermally treated at different temperatures to optimize their electrochemical activity. Thermally processed graphite was characterized by X-ray diffraction, field-emission scanning electron microscopy, Raman and infrared spectroscopy. The electrochemical performances of both anode and cathode half-cells were optimized and finally all‑carbon dual-ion battery was fabricated and tested with the best performing electrodes. For the anode half-cell, spent graphite thermally processed at 800 °C delivered the highest specific capacity of 250 mAh/g at 372 mA/g and cycling stability over 300 cycles. While for cathode half-cell, the spent graphite processed at 650 °C delivered first discharge capacity of about 65 mAh/g at a specific current of 100 mA/g and reasonable stability for 100 cycles. Coupling these anode and cathode, ACDIB displayed an initial discharge capacity of 58 mAh/g corresponding to an energy density of 255 Wh/kg.

Bis-imino-acenaphthenequinone-Paraphenylene-Type Condensation Copolymer Binder for Ultralong Cyclable Lithium-Ion Rechargeable Batteries

Graphite has been the conventional lithium-ion anode for the negative electrode for the past three decades. One of the major challenges for graphite anodes is the exfoliation of graphite framework on deep cycling at a fast current rate, leading to a gradual capacity fade. In this regard, poly(vinylidene fluoride) (PVDF) has been the conventional binder widely used for stabilizing the graphite framework. Unfortunately, its nonconducting nature, slow dissolution in the electrolyte, and poor adherence to the current collector limit its utility as a robust binder for lithium-ion batteries with a long cycle life. Here, we report an n-type conjugated copolymer bis-imino-acenaphthenequinone-paraphenylene (BP) as an alternate binder material for the graphite anode. The BP binder-based anodic half-cells outperformed the PVDF-based counterpart, showing an excellent performance with a reversible capacity of 260 mA h g–1, cyclability up to 1735 long cycles at 1 C rate, and 95% capacity retention. The superior performance of the BP binder was attributed to its ability to provide mechanical robustness to the electrode laminate, maintain electronic conductivity within the electrode, and undergo n-doping in the anodic environment, influencing the formation of a thin solid electrolyte interface with low interfacial impedance.

Combination of Acid-Base Electrolyte at Each Half-Cell with a Single Zeolite Membrane for Crossover Free and Possible Increased Energy Density in an All Aqueous Redox Flow Battery

Instead of an organic medium, a simple change in pH could lead to a high energy density redox flow battery (RFB). Besides, ion crossover and membrane optimization are problems that limit its commercialization. In this investigation, a zeolite-coated ceramic single membrane is adopted in an acid-base pH electrolyte combination for the vanadium (V4+/V3+)/sulfur (S4 2−/2S2 2−) (V/S) redox couple as a model system. First, the potential widening with a change in pH is explained by difference in OCP (open circuit potential) between the acid-acid and acid-base electrolyte combination that differs by 0.8 V. A 300 mV decrease in the V4+/V5+ redox peak potential and the 10 mV increase in the negative direction in the S4 2−/2S2 2− redox peak potential between acid-acid and acid-base electrolyte combination show the pH effect predominant in anodic half-cell than the cathodic half-cell. UV-visible analysis for the migration of vanadium and sulfur ions demonstrates no migration of vanadium and sulfur ions to each other half-cell via zeolite coated ceramic membrane. The current efficiency of 94%, voltage and energy efficiencies of 45%–50% are achieved under the given current density of 5 mA cm−2. In addition, the acid-base combination of V/S RFB system shows an energy density of 233.2 Wh l−1

Influence of a binder on the electrochemical behaviour of Si/RGO composite as negative electrode material for Li-ion batteries

A composite consisting of silicon nanoparticles and reduced graphene oxide nanosheets (Si/RGO) was studied as a promising material for the negative electrode of lithium-ion batteries. Commonly used polyvinylidene fluoride (PVdF) and carboxymethyl cellulose (CMC) served as a binder. To reveal the influence of the binder on the electrochemical behaviour of the Si/RGO composite, binder-free electrodes were also prepared and examined. Anode half-cells with composites comprising CMC as a binder demonstrated the best properties: capacity over 1200 mAh∙g-1, excellent cycling performance and good rate capability up to 1.0C.

(Invited) Solid State Sodium Satteries: From Solid Electrolytes to Functional Device

Li-ion batteries (LIBs) dominate the electrochemical energy storage technology because of their extraordinary performance, high energy density, and long cycle life. Still, the enormously growing demand of Li due to the expanding market raises concerns about the costs and the availability of lithium in the future, necessitating the development of beyond-lithium electrochemical energy storage concepts. Sodium is among the most investigated alternatives for lithium due to its abundance, widespread availability and much lower costs. The simple replacement of lithium with sodium in liquid electrolyte cells while keeping otherwise similar cell design results however in lower energy densities as compared to LIBs due to a higher molar mass, more positive redox potential and higher reactivity of sodium with liquid electrolytes as compared to lithium. In combination with solid electrolytes, however, much higher energy densities can be expected due to a possible use of metallic sodium as an anode instead of currently used hard carbons, opening new perspectives for the development of Na-based electrochemical energy storage systems.Sodium is among the most investigated alternatives for lithium due to its abundance, widespread availability and much lower costs. The simple replacement of lithium with sodium in liquid electrolyte cells while keeping otherwise similar cell design results however in lower energy densities as compared to LIBs due to a higher molar mass, more positive redox potential and higher reactivity of sodium with liquid electrolytes as compared to lithium. In combination with solid electrolytes, however, much higher energy densities can be expected due to a possible use of metallic sodium as an anode instead of currently used hard carbons, opening new perspectives for the development of Na-based electrochemical energy storage systems.Fundamental prerequisite for the development of high-performance solid state sodium batteries is a sufficiently high total conductivity of all its components at room temperature. The latter includes the ionic conductivity of the electrolyte (simultaneously acting as a separator in solid state batteries), the combined electronic/ionic conductivity of the cathode and the anode half-cells, as well as a high conductivity of key interfaces between the electrolyte and the electrode materials. The total conductivity critically relies on the bulk properties of individual materials, but also on their nanomorphology in the component assemblies as well as on the processing- and operation-dependent interface between the materials. The materials challenge therefore goes far beyond the bulk structure level, including the other fundamental aspects of materials chemistry (such as integration of materials into components, optimization of component microstructure, interface properties), electrochemistry (individual contributions to the total impedance, degradation mechanisms upon cell operation), and engineering (development of processing technology enabling fabrication of optimized components).I will give an overview of the sodium solid state battery development that spans from the development of solid state sodium conductors to their processing to functional battery components and finally to the fabrication and testing of the complete cells. I will discuss bottlenecks in the battery performance and will show the concepts for the mitigation of critical steps.

In Situ Detecting Lithium-Ion Batteries Thermal Runaway with Resistance Temperature Detector

Advanced next-generation lithium-ion batteries (LIBs) can only be realized when the thermal safety-related incidents, which have been the roadblocks for development, are mitigated. A variety of advanced works have been proposed for safety enhancement viz., isolating shutdown separators, protective electrode coatings, electrolyte additives. However, they have been stalled from further developments on account of their narrow range in working voltage window, stability, performance, and response time. Also, to date in situ safety devices are known to drastically affect LIBs’ performance. Novel temperature measurement schemes have been developed to help battery management systems (BMS) for improved prediction such as Thermocouples, Thermistors, Fiber Bragg-grating (FBG) sensors, etc. but each has its limitation. Hence, this points towards developing an effective temperature management system that is capable of quick detections, compact, cost-effective, and light-weighted. Here, we are reporting in operando thermal runaway detection for LIBs, from beneath the anode current collector, using an internal resistance temperature detector (RTD). Sensing temperature fluctuations from the anode is more critical compared to the cathode is that it has a solid electrolyte interface (SEI) layer, which is comprised of reduced electrolytic compounds like ROCO2Li, (CH2OCO2Li)2 and ROLi and has lithium stored in graphitic interlayers. During thermal runaway events, decomposition of these compounds and reactions of the charged anode with electrolyte leads to the generation of an enormous amount of heat, which can induce fire, smoke, or explosion. Hence, sensing the anode becomes critical and gives direct access to this heat.Here, we studied three such thermal runway events, viz, external short circuit (ESC), overcharging, and overheat using multiple module calorimetry (MMC) to elucidate the thermal detection capabilities and presence of RTD inside the LIB. During ESC and overcharge tests, temperatures of around 36°C and 48°C were recorded using internal RTDs, respectively. These temperatures were about 9°C and 20°C more than the external RTDs. An interesting statistic about the internal RTD was its detection ability, which for 90% temperature rise was about 14 times faster than compared to the external RTD. RTD embedded mesocarbon microbeads (MCMB) anode half-cell was cycled at 0.25C rate giving a stable average capacity of 238 mAh g-1 over 200 cycles with voltage profile congruent to those reported in the literature. Modeling simulated tests elucidated the prevalence of different regions during thermal runaway events initialed by ESC and overcharge. Additionally, Multimode Calorimetry (MMC) for LIB with embedded internal RTD produced more endothermic peaks beyond 150°C and overall heat generated was 1.75 kJ g-1, which is significantly lower than conventional LIB. RTD assembly has another role of being a passive safety device while placed inside the LIB. Using thermal signatures from internal RTD, future BMS can provide a conducive environment for the LIBs, which would deliver power for high energy density applications such as in the grid-storage and EVs industries.

Influence of Relative Humidity on the Reaction Kinetics in Rubidium Silver Iodide Based All-Solid-State Battery

Our previous study on a rechargeable rubidium silver iodide (RbAg4I5) based all-solid-state battery has shown an exponentially improved performance with increasing relative humidity (RH). Previous galvanostatic charge-discharge measurements revealed that while operating in an ambient environment with a relative humidity (RH) of 100%, the specific energy and energy density of the all-solid-state battery reached 68 Wh kg-1 and 400 Wh L-1, respectively; however, the specific energy decreased by 90% under 10% RH. Here, we investigated the effect of humidity on the electrochemical reaction kinetics in the RbAg4I5 based all-solid-state battery. Four-electrode conductivity measurements of the solid electrolyte unveiled that the humidity had no appreciable influence (~4%) on the conductivity, whilst series cell resistances of half cells evaluated from electrochemical impedance spectroscopy measurements change only 3% within an RH ranging from 35% to 100%. On the other hand, linear sweep voltammetry measurements of anode and cathode half cells showed that increasing the RH from 35% to 100% increased the exchange current density by three orders of magnitude. The relationship between the water vapor adsorption and reaction kinetics was examined by constructing water vapor adsorption isotherms. The trend of exchange current density was attributed mainly to the water adsorption/desorption at the electrode/electrolyte interfaces and a model was proposed to explain the impact of water adsorption on the electrochemical kinetics. These results suggest that the all-solid-state battery operates effectively when exposed to a high humidity environment and can be used in the applications requiring very high reliability. Figure 1

Insight into pre-sodiation in Na3V2(PO4)2F3/C @ hard carbon full cells for promoting the development of sodium-ion battery

Sodium-ion battery has been put into an eager consideration in the large-scale energy storage system, owing to its inexpensive cost ($/kWh) than that of the lithium-ion battery. The gap from research to industry still exists, however, including low energy density and unsatisfactory cycling lifespan in full cells. Here we report a Na-ion full cell with spray-dried Na3V2(PO4)2F3/C (NVPF/C) cathode and pre-sodiated hard carbon (HC) anode. It is demonstrated that the full cells (NVPF-HC), assembled with 100% presodiated HC anode, exhibits the best energy storage capability and rate performance. A remarkable reversible capacity of 114.1 mA h g−1 at 0.5C (attaining 95% of capacity for NVPF-Na anode half-cell), a desirable power performance with 90.6 mA h g−1 at a high rate of 20C, and an impressive cycling life (71.8% capacity retention after 600 cycles at 10C) are achieved. The outstanding battery performance is ascribed to that the electroactivity Na+ in HC can maximize the scavenger effect and forms the more stable solid-electrolyte interface (SEI). Moreover, an HC pre-sodiation degree dependent Na-ion battery performance is proofed. The findings in this paper offer new insights on the electrode design strategy, which facilitates the development of sodium-ion technology.

Effect of relative humidity on the reaction kinetics in rubidium silver iodide based all-solid-state battery

Our previous study on a rechargeable rubidium silver iodide (RbAg4I5) based all-solid-state battery showed an exponential increase of the performance with increasing relative humidity (RH). Here, we investigated the effect of humidity on the electrochemical reaction kinetics at the Ag/RbAg4I5 anode and graphite/RbAg4I5 cathode using three-electrode cells. Four-electrode electrochemical impedance (EIS) measurements were conducted to evaluate the ionic conductivity of the solid electrolyte. The results unveiled that the ionic conductivity varied 4% between 35% and 100% RH in consistence with the variation of series cell resistances of the half cells. On the other hand, linear sweep voltammetry measurements of the anode and cathode half cells showed that increasing the RH from 35% to 100% increased the exchange current density by three orders of magnitude. The relationship between the water vapor adsorption and reaction kinetics was established by introducing water vapor adsorption isotherms. A proportionality was observed between the exchange current density and the number of water layers adsorbed at the electrolyte/electrode interface and a model was proposed to explain the impact of water adsorption on the electrochemical kinetics. These results suggest that the all-solid-state battery operates effectively when exposed to a high humidity environment and can be used for the applications requiring high reliability.

Producing electrical energy in microbial fuel cells based on sulphate reduction: a review.

Combination of the treatment of effluents with high organic loads and the production of electricity is the driving forces stimulating the development of microbial fuel cells (MFC). The increase in electricity production in MFCs requires not only the optimization of the operational parameters but also the inhibition of themetabolic pathways, which compete with electricity production, such as methanogenesis. The presence of both sulphate and sulphide ions in conventional anaerobic reactors hampers the growth of methanogenic archaea and justifies the use of sulphate and therefore sulphate-reducing bacteria (SRB) in the anodic half-cell of MFC. Most importantly, the literature on the subject reveals that SRB are able to directly transfer electrons to solid electrodes, enabling the production of electrical energy. This technology is versatile because it associates the removal of both sulphate and the chemical oxygen demand (COD) with the production of electricity. Therefore, the current work revises the main aspects related to the inoculation of MFC with SRB focusing on (i) the microbial interactions in the anodic chamber, (ii) the electron transfer pathways to the solid anode, and also (iii) the sulphate and COD removal yields along with the electricity production efficiencies.

X-Ray CT 3D Structure Measurement and Performance Evaluation of All Solid-State Lithium-Ion Battery Anode

X-ray computed tomography (CT) measurements with high-pressure compression and performance measurements were conducted for anode half-cells with a sulfide solid electrolyte and different volume ratios of graphite as the active material, in order to elucidate the relationship between the three-dimensional structure and performance of the anodes. The X-ray CT images were captured by a laboratory-scale CT imager and battery performance was measured using charge–discharge cycles and the current interrupt method. It was found that a high volume ratio of active material led to a decrease in the battery charging speed, because there was a decrease in connections between solid electrolyte and active material due to the aggregation of the active materials.

The COVID-19 Pandemic, Part 1: Can Antimicrobial Copper-Based Alloys Help Suppress Infectious Transmission of Viruses Originating from Human Contact with High-Touch Surfaces?

The COVID-19 Pandemic, Part 1: Can Antimicrobial Copper-Based Alloys Help Suppress Infectious Transmission of Viruses Originating from Human Contact with High-Touch Surfaces?

X-Ray CT 3D Structure Measurement and Performance Evaluation of All Solid-State Lithium-Ion Battery Anode

X-ray CT and battery performance measurements of LiIn-SE-Anode (SE + Graphite) half cell are conducted to elucidate the relationship between electrode performance and 3D internal structure. LGPS that is one of the highest lithium-ion conductive solid electrolyte are used in this study. Fig.1 illustrates an experimental setup in this study. The anode half sell is installed in high pressure X-ray CT measurement jig. The X-ray CT are conducted with In-situ high pressure condition (100MPa) to measure the volume ratio of SE and graphite and tortuosity of SE network those can be changed with decompression. The battery performance are measured by a potentiogalvanostat with CC charging and discharging and an electrochemical impedance spectroscopy (EIS) are conducted to measure the overpotential in the cell. The performance measurement and EIS are conducted for the same X-ray CT measured anode half sell, therefore, the battery performance can be directory discussed with 3D structure.Figure 2 illustrates the ratio of actual capacity to theoretical capacity as a function of electrode thickness and volume ratio of active material (graphite). The highest capacity ratio is obtained for thin electrode (30um) and low active material volume ratio (50%) and is decreased by increase in the electrode thickness and the active material ratio.Table.1 shows the electrode structure parameters measured by the X-ray CT and high-frequency and low-frequency resistance measured by the EIS. The high frequency resistance of the anode half-cell is originated from overpotential of lithium ion transportation in SE network and activation overpotential on graphite and that of low-frequency resistance is diffusion of Li-ion in graphite particle. From table.1, in the case with graphite ratio of 50%, both high frequency and low frequency resistance are increased with increase in the electrode thickness. It is considered that the low frequency resistance is increased with the increase of SE network resistance by increase in the length of the lithium-ion transportation length. The increase of the electrode thickness decreases the lithium ion flux for each graphite particle and the diffusion in the graphite is suppressed and the low frequency resistance is increased. The increase of graphite volume ratio dramatically decreases the ratio of actual capacity to theoretical capacity as shown in fig.2. The tortuosity of SE network that has a positive correlation to the resistance of the SE network is increased with the increase in the graphite volume ratio. It can be a reason of the increase of the high frequency resistance. Moreover, the specific surface area between SE and graphite is decreased with the increase in graphite volume ratio. It means the graphite is condensed in the electrode and the contact surface of the graphite to SE is decreased and the diffusion length of lithium ion in the graphite is increased. This suppression of the lithium ion diffusion in graphite particle is corresponds to the increase of the low frequency resistance as shown in table 3.From the mentioned above, it can be said that the battery performance improvement with high volume ratio of graphite for would be achieved with the improvement of the dispersiveness of graphite and ion conductivity of the solid electrolyte. Figure 1

A newly synthesized green corrosion inhibitor imidazoline derivative for carbon steel in 7.5% NH4Cl solution

Corrosion and corrosion inhibition behaviors of steel Q-235 were studied in 7.5% NH4Cl solution with the newly synthesized inhibitor by potentiodynamic polarization together with tests of electrochemical impedance spectroscopy and weight loss measurements in 298–338 K temperature range. The new inhibitor 2-(2-heptadecyl-4, 5-dihydro-1H-imidazole-1-yl) ethanol (HDIE) is synthesized with the help of microwave radiations in solvent free conditions. The results showed that inhibition efficiency above 90% is achievable at 298 K with 0.5 mML−1 inhibitor concentration. The Adsorption studies revealed that HDIE follows Langmuir model and its adsorption mechanism was mixed-type with predominant effect on anodic half cell. It was seen from the EDS characterization of corroded steel surfaces that the HDIE retarded the corrosion by impeding the chloride attack. Quantum chemical calculations demonstrated that the imidazoline ring and hetero-atoms were active sites. Moreover, an inhibition mechanism was proposed on the basis of the quantum chemical calculations and experimental corrosion studies.

An insight of bioelectricity production in mediator less microbial fuel cell using mesoporous Cobalt Ferrite anode

Microbial Fuel Cells (MFCs) are an alternative sustainable approach that utilizes the bacteria present in waste water as a bio-catalyst and produce electricity. Herein, Cobalt Ferrite (CF) is fabricated hydrothermally and deposited over graphite sheet to envision a cost-effective MFC anode. The intrinsic biocompatibility, together with mesoporous structure of CF greatly enhanced the microbial colonization. A comparative time dependent study of kinetic activity of CF/Graphite in domestic waste water and artificial waste water is reported. Electrochemical characterization (CV & EIS) indicated the process of active bio film formation on anode from day 1st to day 20th and then restricted bio film till day 30th. Improved extracellular electron transfer of exoelectrogens due to the variable valence state and high redox stability of CF, facilitated the MFC to deliver an excellent power density (1856 mW m−2) with the maximum anodic half–cell potential of 0.65 V in waste water. High capacitance (280%) and appropriate pore size (9.3 nm) of CF formed a capacitive bridge for an effective flow of electrons generated by the electro active bacteria. Therefore, use of noble metal free, low cost anodic material Cobalt Ferrite with long-term cell stability makes it a promising and sustainable power source for commercial application.

The Use of Succinonitrile as an Electrolyte Additive for Composite-Fiber Membranes in Lithium-Ion Batteries

In the present work, the effect of temperature and additives on the ionic conductivity of mixed organic/ionic liquid electrolytes (MOILEs) was investigated by conducting galvanostatic charge/discharge and ionic conductivity experiments. The mixed electrolyte is based on the ionic liquid (IL) (EMI/TFSI/LiTFSI) and organic solvents EC/DMC (1:1 v/v). The effect of electrolyte type on the electrochemical performance of a LiCoO2 cathode and a SnO2/C composite anode in lithium anode (or cathode) half-cells was also investigated. The results demonstrated that the addition of 5 wt.% succinonitrile (SN) resulted in enhanced ionic conductivity of a 60% EMI-TFSI 40% EC/DMC MOILE from ~14 mS·cm−1 to ~26 mS·cm−1 at room temperature. Additionally, at a temperature of 100 °C, an increase in ionic conductivity from ~38 to ~69 mS·cm−1 was observed for the MOILE with 5 wt% SN. The improvement in the ionic conductivity is attributed to the high polarity of SN and its ability to dissolve various types of salts such as LiTFSI. The galvanostatic charge/discharge results showed that the LiCoO2 cathode with the MOILE (without SN) exhibited a 39% specific capacity loss at the 50th cycle while the LiCoO2 cathode in the MOILE with 5 wt.% SN showed a decrease in specific capacity of only 14%. The addition of 5 wt.% SN to the MOILE with a SnO2/C composite-fiber anode resulted in improved cycling performance and rate capability of the SnO2/C composite-membrane anode in lithium anode half-cells. Based on the results reported in this work, a new avenue and promising outcome for the future use of MOILEs with SN in lithium-ion batteries (LIBs) can be opened.

Na–Ge glass anode network mixed with bismuth oxide nanocrystallites: A high capacity anode material for use in advanced sodium-ion battery design

Exploring the growing phenomenon of amorphous intermediate domains at nanoscale and its application as flexible active centres in a glass anode network is decisively significant to enhance sodium-ion battery performance. The outstanding stability of nanosized h-Na3Bi and NaGe domains in the glass anode network makes it more electrochemically efficient and increases its ionic conductivity. Subsequently, improved cycle stability and rate capability of glass anode half-cell have been achieved due to optimum void space between domains and open glass network. It also exhibits enhanced ability to withstand extensive volume variations during the repetitive sodiation/de-sodiation process. The size of the amorphous intermediate domains, structure, and lattice planes separation has been estimated based on the HRTEM and SAED images. The advantages gained by the growth of amorphous domains in the sodium-germanate glass network highlights its potential application as high-performance anode components for the advancement of Na-ion battery (NIB) efficiency.