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The objective of this research is to explore the role of social media on employee recruitment. As technology continues to grow, human activities cannot be separated from the use and benefits of technology. Technology also helps companies run their business more efficiently. Social media also plays a crucial role in the recruitment process to find potential candidates. This systematic review paper is written based on the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) method. The findings show that social media can be used as an effective platform for a faster and more flexible recruitment process. Social media recruitment can also provide advantages for both in terms of cost and time. Furthermore, social media can be a tool for employers to obtain information about candidates' backgrounds

Rechargeable sodium-ion batteries (SIBs) have received significant attention as a promising alternative to traditional lithium-ion counterparts for large-scale energy storage applications owing to the low cost and abundance of sodium resources. Herein, we demonstrate the photonic irradiated mesoporous reduced graphene oxide (rGO)-TiO2 nanocomposite architectures using environmentally benign, ultrafast split-second (millisecond) intense pulsed light (IPL) process at room temperature. The photonic IPL irradiation spontaneously triggers the deoxygenation of graphene oxide (GO) and the simultaneous structural engineering of TiO2 nanocomposites. The precisely controlled IPL irradiation (energy density of 10 J cm−2) exhibits excellent conductivity, high surface area, and outstanding electrochemical performance as a green anode material for SIBs. The photonic IPL irradiated rGO-TiO2 nanocomposite delivers a high reversible capacity of 244 mAh g−1 at 0.1 Ag-1, a high rate performance of 112 mAh g−1 at 1 Ag-1, and high cycling stability compared to pristine GO-TiO2 and conventional furnace annealed rGO-TiO2 (FH-rGO-TiO2) nanocomposites. The detailed electrochemical analysis suggests that the improved capacitance contribution results from the fast kinetics of the IPL irradiated rGO-TiO2 nanocomposite anode. This work provides new insight into the fabrication of versatile, cost-effective techniques for developing advanced electrode materials for energy applications.

Achieving a highly active cathode surface with extremely efficient electrocatalysts for oxygen reduction kinetics is a fundamental necessity for durable fuel cells. Developing such active materials into desirable nanostructures is crucial in the pursuit of electrocatalysis. A facile preparation of cobalt decorated nitrogen and sulfur co-doped carbon nanostructures (Co–NSC) with the added advantage of Zeolitic imidazolate frameworks (ZIF), ZIF 67@ZIF 8 is reported here. The as-prepared Co, N, S, co-doped carbon (Co–NSC) electrocatalyst comes under platinum group metal-free (PGM-free) catalysts which intends to replace the scarce and highly expensive commercial Pt catalysts. Facile preparation of the Co–NSC catalyst that is scalable, low cost and highly ORR active makes the material advantageous. Co–doping sulfur has dramatically enhanced the intrinsic catalytic activity of the catalyst, and the degree of variation in sulfurization greatly influences the overall catalytic property. Co–NSC 200 with high sulfur doping exhibit a positively shifted onset potential of 0.81 V, and a high yielding current density of 5.5 mA cm−2 at 20 mV s−1.

The ABO3−δ-type perovskite oxides are highly desirable electrocatalysts with interesting surface structures that could be modified to bring out their excellent catalytic performance. The La0.6Sr0.4...

Cellulose in various forms possesses high strength, low density, and high aspect ratio with a three-dimensional open network structure, making them ideal candidates as current collectors in energy conversion application. Herein, a surface rough-cellulose-based bamboo fiber with unique and naturally-convoluted morphology is adopted for the fabrication of catalytically active cobalt substrates for water splitting. For the efficient evolution of hydrogen and oxygen, cobalt-based bimetallic alloys, namely, cobalt–molybdenum and cobalt–iron, were electrodeposited. The proposed system possesses a highly macro-porous network of hexa-filament micro-fibrils that demonstrate exceptional catalytic activities. In quantitative terms, the anodic and cathodic current density of 50 and −10 mA cm−2 at respective overpotentials (η) of 250 and 46 mV with a low activation energy (Ea) of 28 kJ mol−1 were achieved. Moreover, when operated under harsh industrial standards of 5 M KOH@343 K, electrodes demonstrate excellent water electrolyzing catalytic activities (η-100(HER) = 147 mV; η100(OER) = 209 mV). This work, thus, promises a new strategy for designing electrode systems that are highly efficient as well as economical as the substrate was obtained from a ubiquitous earth-friendly material for energy conversion application.

Perovskites are a challenging new class of highly efficient bifunctional catalysts that hold huge significance in advanced batteries and water electrolysis. The surface chemistry and surface electr...

Purpose: Setting the context of exploration in beauty clinic industry, the present study aims to examine the influence of SMM on the four dimensions of brand equity: brand awareness, brand association, perceived quality, and brand loyalty. Theoretical framework: The scholarly community is witnessing a marked increase in interest regarding the impact of social media marketing (SMM) on brands. However, despite this trend, the literature concerning the effects of SMM on beauty clinic brands remains scant. Design/methodology/approach: A cross-sectional survey, facilitated through self-administered online methods, was executed among a sample of customers who had availed themselves of the beauty treatment services provided by the Zap beauty clinic within the past annum. The data gathered was subjected to analysis via the utilization of Structural Equation Modelling (SEM) techniques, utilizing the software platforms SPSS and SmartPLS. Findings: The results indicate that SMM exerts a positive and significant impact on brand awareness, brand association, perceived quality, and brand loyalty. Research, Practical & Social implications: The findings of this investigation are anticipated to provide valuable understandings into the effectiveness of SMM on brand equity within the beauty industry which can improve marketing and branding strategies and building competitive advantage. Originality/value: This study is an original attempt to propose and test a theoretical framework, explaining the relationships among SMM on the four dimensions of brand equity: brand awareness, brand association, perceived quality, and brand loyalty in the beauty clinic context.

Reverse electrowetting-on-dielectric (REWOD) is a novel energy harvesting technique that has been gaining considerable amount of attention owing to its high power output even with the small amount of disturbance. To enhance the output power of REWOD, the dielectric layers in the system require a high capacitance. Nevertheless, current leakage is inevitable in such high-k dielectric materials. In this work, the application of a high-k dielectric material TiO2 has been investigated along with a new leakage barrier layer Al2O3 that acts as a lamination, in order to minimize the current leakage and maximize the power output. As expected, the laminated structure with TiO2 and Al2O3 exhibited reduced current leakage and relatively high capacitance compared to the single layer of TiO2 or Al2O3, respectively. As the electrical energy is generated through the interaction of liquid droplets and the multilayered dielectric film, the energy-harvesting performance displayed different behavior about current generation with respect to the top surface material that is in contact with the conductive droplet. Overall, the laminated REWOD energy harvesting system produced an enhanced power density of 15.36 mW cm−2 at a low bias voltage.

Lipids extraction from wet and unbroken microalgae (Chlorella vulgaris) using subcritical water with aid of co-solvents has been investigated. Lipids extraction from wet and unbroken microalgae has a crucial role in order to eliminate dewatering and drying steps. Subcritical water is able to extract lipids from feedstock with high water content. This work was conducted to study several factors affecting in subcritical water extraction (SWE) from wet and unbroken microalgae. In this study, effect of co-solvent types (without co-solvent, chloroform, methanol, ethanol, ethyl acetate, and n-hexane) under subcritical water (microalgae = 5g (dry weight), moisture content= 94.12%, T= 160°C, P = 80 bar, t= 30 min), extraction time (15 min, 30 min, 1 h, 3 h, and 5 h), and temperature (160o C, 180o C and 200o C) on yield of lipids were investigated orderly. Yield of lipids obtained without co-solvent (water polarity index = 10.2) and with co-solvents of methanol (PI=5.1), ethanol (PI=5.2), chloroform (PI=4.1), ethyl acetate (PI=4.4), and n-hexane (PI=0.1) were 38.73%, 26.47%, 26.12%, 51.93%, 53.40%, and 25.59%, respectively compared to the yield of lipids extracted using Bligh and Dyer method. Ethyl acetate is solvent with moderate PI, therefore can extract more lipids that is also have moderate polarity. Ethyl acetate shows a good performance to extract lipids from wet and unbroken microalgae because ethyl acetate can extract broader range of lipids including neutral and polar lipids. This study also found that increasing of extraction time and temperature to extract lipids in subcritical water condition can increase yield of lipids.

The high theoretical energy density of lithium-air batteries has attracted the attention of many researchers as this system is expected to fulfill the demands radically from all sectors. Unfortunately, the issues such as deposition of undesirable discharge in the cathode, formation of lithium dendrites, and decomposition of electrolytes hamper it from commercialization. In the present work, viologens carrying different positive charges were synthesized and used as a catalyst in the carbon-assisted air cathode for the first time, and its cycling performance was analyzed. The lithium air cell with monomeric viologen offered highest discharge capacity and the deposition of Li2O2 in the cycled cathode was confirmed by XRD and FT-IR analyses.

Producing low–cost non–precious metal catalysts in large scales to be used as air–cathodes for efficient oxygen reduction and evolution reactions in Li–O2 batteries is a demanding task. Herein, we report a simple technique for the synthesis of a carbide composite comprising molybdenum and tungsten with a robust nanowire structure. When applied as an air–cathode electrocatalyst in Li–O2 batteries, the nanowire composite delivered high specific discharge capacity with reversibility and cyclability. This work provides a novel approach for tailoring nano–architectures and thereby achieving high–power Li–air batteries.

Penelitian Tindakan Kelas dilatarbelakangi oleh hasil penguasaan konsep keliling bangun datar peserta didik kelas III SDN Soropadan masih rendah atau belum mencapai kriteria ketuntasan minimal (KKM). Penelitian ini bertujuan untuk meningkatkan penguasaan konsep keliling bangun datar dengan model pembelajaran pair check pada peserta didik kelas III SDN Soropadan Surakarta tahun ajaran 2020/2021 yang berjumlah 28 peserta didik dan diambil sampel 8 anak.Penelitian tindakan kelas yang menggunakan model Kemmis dan Mc. Taggart. Pada siklus I ketuntasan klasikal mencapai 37,5% dan nilai rata-rata 71,63. Pada siklus II, penguasaan konsep keliling bangun datar peserta didik memperoleh ketuntasan klasikal 87,5% dan nilai rata-rata 82,5. Berdasarkan hasil penelitian tersebut dapat disimpulkan bahwa implementasi model pair check dapat meningkatkan penguasaan konsep keliling bangun datar pada peserta didik kelas III SDN Soropadan Surakarta tahun ajaran 2020/2021.

The purporse of this research is to improve concept mastery of Indonesia independent struggle by using CRH model for 5th grade students of SD N Bulakrejo 02 Sukoharjo on 2018/2019. This research is a Classroom Action Research (CAR). This study was conducted in 2 cycles with each cycle consisting of planning, implementing actions, observing, and reflecting. This research uses content validity, technique triangulation, and source triangulation. The results of this study prove that the average pretest score is 58,69 with classical completeness of 12,5%. In the first cycle the average value increased to 72,87 with classical completeness of 43,75%. In the second cycle there was an increase to 84,18 with 87,5% classical completeness. The conclusion of this study is that by CRH learning model, it can improve the concept mastery of Indonesia independent struggle in 5th grade students of SD N Bulakrejo 02 Sukoharjo on 2018/2019.

The choice of electrolyte solvent is expected to play a key role in influencing the lithium-oxygen battery performance. The electrochemical performances of three electrolytes composed of lithium bis (trifluoromethane sulfonyl) imide (LiTFSI) salt and different solvents namely, ethylene carbonate/propylene carbonate (EC/PC), tetra ethylene glycol dimethyl ether (TEGDME) and dimethyl sulfoxide (DMSO) are investigated by assembling lithium oxygen cells. The electrolyte composition significantly varied the specific capacity of the battery. The choice of electrolyte also influences the overpotential, cycle life, and rechargeability of the battery. Electrochemical impedance spectra, cyclic voltammetry, and chronoamperometry were utilized to determine the reversible reactions associated with the air cathode.

Iron phthalocyanine supported on graphite nanofibers (GNF_FePc) were synthesized using a simple solvothermal process and characterized using various structural analyses. GNF_FePc were employed as bifunctional electrocatalysts in the air cathode of lithium-oxygen batteries. Galvanostatic charge–discharge tests, cyclic voltammetry, and electrochemical impedance spectroscopy were performed to assess the Performance of Li-air batteries. The air-cell delivered a high specific capacity of ∼5500 mAh/g at the first cycle which remained close to 90% of that value after 4 cycles. The reversibility was nearly 100% for all the four cycles with comparatively lower over potential.

We have synthesized three dimensional architectural α–MnO2/RuO2 hybrid nanostructures with three different compositions of (75:25), (69:31) and (50:50) by hydrothermal approach and evaluated their bifunctional electrocatalytic activity for Li–O2 battery applications. The morphology of the α–MnO2/RuO2 nanostructures changed from sharp sea urchins to solid nanospheres with increasing RuO2 content in the composition. The variations observed in physical, structural, morphological and electrochemical properties were characterized with respect to the MnO2/RuO2 concentrations by step by step analyses. MnO2 exhibited better ORR catalytic activity, while RuO2 revealed superior OER catalytic activity. Among the concentrations investigated, α–MnO2:RuO2 (75:25) exhibited superior catalytic activity for oxygen reduction and evolution reactions in aqueous media. This excellent catalytic activity logically led us to apply it as air-cathode catalyst in Li–O2 cell, which produced a maximum capacity of >8100 mAh g−1 with high columbic efficiency and cyclability. The superior performance of the hybrid nanostructure is mainly attributed to its structural and compositional design which favors the electrochemical activity. Based on a careful investigation on the structural characterizations, the growth mechanism of the 3D nanostructured α–MnO2/RuO2 mixed oxides is discussed in detail.

Platinum (Pt) and iridium (Ir) catalysts are well known to strongly enhance the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) kinetics, respectively. Pt–Ir-based bimetallic compounds along with carbon-supported titanium oxides (C–TiO2) have been synthesized for the application as electrocatalysts in lithium oxygen batteries. Transition metal oxide-based bimetallic nanocomposites (Pt–Ir/C–TiO2) were prepared by an incipient wetness impregnation technique. The as-prepared electrocatalysts were composed of a well-dispersed homogenous alloy of nanoparticles as confirmed by X-ray diffraction patterns and Fourier transform scanning electron microscopy analyses. The electrochemical characterizations reveal that the Pt–Ir/C–TiO2 electrocatalysts were bifunctional with high activity for both ORR and OER. When applied as an air cathode catalyst in lithium-air batteries, the electrocatalyst improved the battery performance in terms of capacity, reversibility, and cycle life compared to that of cathodes without any catalysts.

We report the synthesis of two-dimensional (2D) Co3S4 in a nanothickness sheetlike morphology via simple hydrothermal process and its application to electrochemical energy-storage devices. The presence of unique mesopores with a combination of core/shell nanoparticles in the nanosheets showed superior electrochemical performances as a negative electrode for a Li-ion battery (LIB) and an electrocatalyst in Li–O2 battery applications. A high discharge capacity of ∼968 mAh g–1 is noted after 60 cycles with excellent cycling stability when evaluated as an anode for a LIB. On the other hand, the first discharge capacity of ∼5917 mAh g–1 is observed with a high reversibility of 95.72% for the Li–O2 battery point of view. This exceptional electrochemical performance in both applications is mainly attributed to the presence of mesoporous with core/shell 2D nanostructure, which translates more catalytic bifunctional (oxygen reduction reaction/oxygen evolution reaction) active sites for Li–O2 and sustains the volum...

The graphene/cubic cobaltite oxide nanosheets (rGO/Co 3 O 4 ) with a face centered cubic crystalline structure are synthesized and are exploited as effective cathode catalysts in high performance Lithium-air batteries. The morphological images enunciate that 220 nm average diameter of Co 3 O 4 nanosheets are effectively anchored over the graphene sheets and the diameter of individual nanoparticles that construct the cubic nanosheets is 5 nm. The growth and composite formation mechanisms of prepared nanostructures are identified from Raman and FT-IR spectroscopic techniques. rGO/Co 3 O 4 composite exhibits a lower voltage, high discharge capacity of 4150 mAh g −1 and displays superior cyclability without any capacity losses, signifying the excellent rechargeability of the fabricated electrodes. The post mortem analysis of electrodes specify the existence of lithium peroxide (Li 2 O 2 ), lithium oxide (Li 2 O) and lithium carbonate (Li 2 CO 3 ) discharge products, revealing the involved electrochemical reaction of Lithium-air batteries. The excellent electrochemical properties of rGO/Co 3 O 4 composite is due to the combination of rapid electrokinetics of electron transport and high electrocatalytic activity toward oxygen reduction reaction given via the synergetic effects of rGO and cubic Co 3 O 4 nanosheets. These findings provide fundamental knowledge on understanding the influence of morphological and structural properties of graphene based nanostructures toward Lithium-air battery performances.

The high performance of α–MnO2/NGNF catalyzed air cathode for Li–O2 battery is reported in this article. The α–MnO2 nanorods are successfully grown on highly conductive nitrogen doped graphite nanofibers with caterpillar like morphology by a simple hydrothermal technique. The as–prepared α–MnO2/N–GNF catalyst exhibits better electrocatalytic performance in terms of oxygen reduction and evolution reactions in the air cathode exhibiting comparatively low overpotential. In addition to the low overpotential, α–MnO2/NGNF catalyzed Li–O2 battery also show high capacity, reversibility and rate capability. The combined effect of α–MnO2 and N–GNF for facilitating electrochemical reactions between Li and O2 is described for improving energy and columbic efficiency of Li–O2 battery.

The need for an alternative electrocatalyst to replace Pt-based noble materials is a major concern of the Li–air battery technology. In this work, α-MnO2 nanorods are synthesized by a simple hydrothermal technique and are modified with palladium (Pd) nanoparticles to form Pd-deposited α-MnO2 (Pd/α-MnO2) nanostructures. The physical characteristics of the thus prepared materials are analyzed by X-ray diffraction (XRD), SEM, and Brunauer–Emmett–Teller (BET) techniques. These analyses confirmed the successful synthesis of 8∼10-nm-sized Pd nanoparticles deposited on 82∼85-nm-sized α-MnO2 nanorods. The catalytic activities of the synthesized Pd/α-MnO2 nanostructure for oxygen reduction reaction and evolution reaction were studied by measuring linear sweeping voltammograms in aqueous solution. The as-prepared material exhibited high electrocatalytic activities which were comparable to that of the commercial Pt/C catalysts. The Pd/α-MnO2 nanostructures were then examined as a bifunctional electrocatalyst in the air cathode of Li–air batteries in non-aqueous media. The Li–air batteries fabricated with the Pd/α-MnO2 catalyst deliver a high discharge capacity with low overpotential compared to the other batteries without Pd deposition or any catalyst.

Small and Medium Enterprises are the backbone of major economy and empirical studies prove that small firms are more efficient and innovative in their operation, product development and marketing strategies. The objective in this study is to analyze marketing strategies of SME’s running entrepreneurs in Touliang Oki village. This study is qualitative studied about Marketing Strategy of Small and Medium Size Enterprises. A field survey method was faced to faced interviews were recorded to analyze the marketing strategies of Micro Sall Medium Enterprise Touliang Oki is one of the village in Minahasa, North Sulawesi. Most of them produce Furniture froom wood. Marketing strategy that they use is door to door and online shopping (facebook and whatsapp) strategy. Their innovations were in the shape of unique designs that not only meet the need of customers. Their services are innovative in a sense that they satisfy the customers. They also faced barriers like lack of raw material in this case they are used wood for the raw material and also they are still use standard machine makes their production is not maximal. Findings suggest to build initiatives some programs for students and lecturers to become business consultant of SME in Indonesia.Keywords: marketing strategy, micro, small, medium enterprise

The metal-based catalysts have been playing a major role in various industrial processes, whereas carbon based nanomaterials have recently been demonstrated to be promising metal-free alternatives for low cost catalytic processes. The doping of nitrogen in carbon and the electrocatalytic properties of the nitrogen doped carbon for oxygen reduction reactions are investigated in this article. We propose a simple method for doping nitrogen in various carbon materials like carbon black and ketjen black, and comparatively studied their physical and electrochemical characteristics. Raman and XPS analyses show significant peak shifts of their characteristic peaks caused by nitrogen doping on the surface of carbon materials. N-doped carbons show higher surface area in Brunauer, Emmett and Teller surface area analysis and more porous structure than undoped carbons in scanning electron microscope images. The N-doped sample was also ball milled to study the surface properties. All samples, i.e. undoped, N-doped and N-doped ball-milled carbons were compared for electrocatalytic activity by cyclic voltammetry and oxygen reduction reaction measurements. Nitrogen doped carbons exhibit better electrocatalytic activity with high mass activity and positive shift of peak potential than undoped samples with electron transfer number of 3.6 close to that of commercial Pt/C.

Carbons derived by the pyrolysis of Sorona activated by ZnCl₂ in the ratio of 1:20 and non-porogen Sorona carbons are used as the electrode materials in asymmetric electrochemical supercapacitors and electrochemical behavior is investigated. Scanning electron microscopy (SEM) reveals the porogen free carbons show a flake-like structure and the ZnCl₂-treated Sorona carbons have a loose, disjoint structure without any particular shape. Cyclic voltammetric (CV) studies show specific prolate rectangular shape and gives good capacitive properties.

Increasing demand of energy, the depletion of fossil fuel reserves, energy security and the climatechange have forced us to look upon alternate energy resources. For today’s electric vehicles that runon lithium-ion batteries, one of the biggest downsides is the limited range between recharging. Overthe past several years, researchers have been working on lithium–air battery. These batteries couldsignificantly increase the range of electric vehicles due to their high energy density, which couldtheoretically be equal to the energy density of gasoline. Li-air batteries are potentially viable ultra-high energy density chemical power sources, which could potentially offer specific energies up to3000 Whkg −1 being rechargeable. This paper provides a review on Lithium air battery as alternateenergy resource for the future.Keywords: Porous air cathode, Catalyst, Lithium air battery, Electrolyte, Energy storage Received March 3, 2012 : Accepted March 27, 2012 1. Introduction Depletion of global fossil oil resources has been thetheme topic of the world economic and political cir-cles over the past decades. How the alternatives can beexploitable, while being economically cost-effective,are the key factors in coming up with conclusions andmaking decision on the part of consumers. Over thepast several decades, the consumer countries havebeen weighing up the use of other resources, or substi-tutes, such as solar, water, wind, nuclear etc. Althoughhuge research works have been done, it sounds a seri-ous step has not been taken yet; mainly because therehave been gigantic amount of this noble energy car-rier, namely the oil, comparing with other substituteresources being highly cost effective. So all this havemade weak incentives for the use of other resources.But over the past several years, researchers have beenworking on an alternative battery called a lithium–airbattery which gives the energy density almost equiva-lent to the gasoline. By the use of this battery in elec-tric vehicles just by changing the electrode in thelithium ion to air, it would be possible for a battery ofthe same size and weight to hold up to 10 times moreenergy-potentially harnessing the same energy den-sity as petrol. Such lithium–air batteries have an anodemade of lithium which is oxidized by the oxygen cath-ode (drawn from environment air), releasing energy.Pumping electricity into the battery reverses the proce-dure, pushing out the oxygen and leaving the lithium.In 1996, Abraham and Jiang

particles were prepared using avian egg membrane as a template at 800 °C. The preparedmaterials were subjected to XRD, SEM, TEM and Raman spectroscopic studies. Cyclic voltammetry studyshows a single step oxidation and reduction process. Electrochemical lithium insertion behavior of thematerials was examined in coin cells of the 2032 configuration. The material showed a discharge capacity 600mAh/g even after 20 cycles. Key Words: Oxides, Nanostructures, Electron microscopy, Electrochemical propertiesIntroductionThe evolution of lithium-ion batteries can be traced toproblems associated with the use of metallic lithium inrechargeable lithium batteries. Although graphite is the mostpopular anode material in lithium-ion batteries, with aspecific capacity of only 372 mAh/g, it fares poorly com-pared to metallic lithium with a specific capacity of 3862mAh/g. Thus, great efforts are being made towards develop-ment of a variety of other anode materials such as lithium-alloying metals, electro-active polymers and silicon. Researchin such high-capacity anode materials is driven by demand-ing power requirements in emerging applications as inelectric vehicles. Conventional wisdom on electrochemicalinsertion reactions in lithium-ion batteries requires electro-nically conducting electrode materials with crystallographicvoids that can support lithium diffusion. In that sense,interstitial-free 3d-metal oxide structures are consideredunsuitable for intercalation chemistry. Recently, however,there has been a spurt in papers reporting the use of severaloxides, oxysalts, nitrides, fluorides, phosphides, sulphidesand borides as anode materials for lithium-ion batterychemistry.

For recent lithium-ion batteries (LIBs), there have been lots of researches about convert liquid-phase electrolyte to solid-state electrolyte (i. e. all-solid-state battery) to improve safety and stability. Solid-state electrolyte materials have to satisfy some criteria including high ionic conductivity at room-temperature, chemical stability against reducing environment, and mechanical strength. Many solid-materials for electrolyte have been researched, including perovskite, garnet, and sulfide-type of materials. Among them, garnet-type based lithium lanthanum zirconium oxide (LLZO, Li7La3Zr2O12) has been received attention due to its high ionic conductivity (~10-4 S/cm at room temperature) and wide electrochemical stability window (~6 V versus Li/Li+). The main issue of LLZO is the high interfacial resistance with anode and cathode materials such as Li metal and LiCoO2. Many researchers have tried to understand the cause of this interfacial resistance for LLZO. K. Park et al. researched about the cathode/electrolyte (LLZO) interface and revealed co-diffusion and second-phase formation of LLZO at high-temperature [1]. M. Zarabian et al. reported that spin-coated LLZO on the LiCoO2 pellet fabricated at low-temperature (~400oC) and co-diffusion of La and Co at the interface by using X-ray photoelectron spectroscopy (XPS) [2]. They commonly suggested that elevated temperature make chemical interaction and this make high interfacial resistance. In this study, we adopted novel sintering method, flash light annealing (FLA) process, to fabricate LLZO solid-electrolyte. This method is also called rapid, cool sintering because of its unique characteristics compared to conventional sintering methods [3]. FLA uses instantaneous high current to generate intensive pulsed light (IPL), and irradiate IPL toward the specimen to sinter the materials. Unlike the conventional sintering methods, this novel method has lots of advantages including availability of treatment at STP and fast sintering time (~ a few ms). Rapid sintering process gives no time for the diffusion at the interface, thus the interfacial resistance between cathode and LLZO solid-electrolyte must be reduced. We fabricated LLZO solid-electrolyte on the commercial LiCoO2 pellet by using solution-based spin-coating method and sintered the film by using FLA method. XPS and energy-dispersive X-ray spectroscopy (EDX) analysis were conducted to observe interface and diffusion of La and Co elements. Also, X-ray diffraction (XRD) method was used to investigate sintering ability of FLA through crystallinity development. The interfacial resistance between LiCoO2 and LLZO solid-electrolyte was analyzed by electrochemical impedance spectroscopy (EIS) through cross-plane set-up.

The single step hydrothermal synthesis of well-dispersed cobalto-cobaltic oxide (Co3O4) cubic nanocrystals has been reported. Microstructure and phase have been unambiguously characterized by XRD, TEM and Raman spectroscopy. Powder X-ray diffraction (XRD) and Raman spectrum showed that the as-prepared sample was of cubic spinel structure. Transmission electron microscopy indicated that the Co3O4 nanocrystals were cubical with the crystallite size in the range of 20–30 nm. Since the particle size of the powdered samples were found to be equivalent from both TEM and X-ray diffraction technique, it can be expected that the nanocubes are single crystalline. The average BET surface area was found to be 75 m2 g− 1 and the average pore diameter was found to be 15 nm.

A novel Fe(3)O(4)/CNT nanocomposite was synthesized and employed for the modification of carbon paper anode in a mediator-less microbial fuel cell (MFC) to enhance its performance. The Fe(3)O(4)/CNT composite modified anodes with various Fe(3)O(4) contents were investigated to find the optimum ratio of the nanocomposite for the best MFC performance. The Fe(3)O(4)/CNT modified anodes produced much higher power densities than unmodified carbon anode and the 30wt% Fe3O4/CNT modified anode exhibited a maximum power density of 830mW/m(2). In the Fe(3)O(4)/CNT composite modified anode, Fe(3)O(4) helps to attach the CNT on anode surface by its magnetic attraction and forms a multi layered network, whereas CNT offers a better nanostructure environment for bacterial growth and helps electron transfer from E.coli to electrode resulting in the increase in the current production with the catalytic activity of bacteria. The electrocatalytic behavior and all possible mechanism for their better performance are discussed in detail with the help of various structural and electrochemical techniques.

For the further advancement of lithium air battery, the design of a new promising bifunctional electrocatalyst is necessary to improve oxygen reduction and evolution reactions (ORR and OER) kinetics during discharge and recharge processes. In this work, three dimensional (3D) α–MnO2/RuO2 mixed oxides were designed and synthesized using simple hydrothermal method. The morphology of the mixed oxides changed from sea urchin shaped nanostructures to nanospheres with the increase of RuO2 content in the mixed oxides. The growth mechanism of the mixed oxides have been studied by analyzing their step by step growth and development through various characterization techniques such as x-ray diffraction, scanning electron microscopy, transmission electron microscopy (TEM), cross sectional TEM and electron dispersive spectrum, etc. It was found that α–MnO2 and RuO2 significantly served as oxygen reduction and evolution reaction catalysts, respectively, indicating that the mixed oxide is suitable as bifunctional catalyst for Li–O2 battery. Among the four different α–MnO2/RuO2 composition ratios, (75:25) appeared to be the optimum ratio for the mixed oxides with superior activity for both ORR and OER. The superior performance of (75:25) ratio can be attributed to its structural and compositional design which aid in the better catalytic performance. When applied in Li–O2 battery system, the (75:25) ratio exhibited excellent performance with maximum capacity of >8100 mAh/g, high coulombic efficiency and cyclability.

Li-air batteries, which are considered to offer much higher energy density than the current Li-ion batteries suffer from poor cycle life due to electrolyte decomposition and clogging of the air cathode by insoluble discharge products. Efficient bifunctional catalysts could improve the stability of Li-air batteries by lowering the overpotential and prolonging the battery cycle life. This study focuses on Iron phthalocyanines (FePc) as possible bifunctional electrocatalysts. Metal phthalocyanines were utilized mainly because of their structural analogy which could be fine- tuned by the metal being used, accessibility, and low cost. In this work, firstly, FePc supported on graphite nanofibres (GNF) was investigated as solid electrocatalyst in non-aqueous LiTFSI (TEGDME) electrolyte. Secondly, FePc was dissolved in the non-aqueous electrolyte and studied as liquid catalyst with GNF cathode. FePc/GNF (solid catalyst) delivered superior electrocatalytic performance for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) comparable to that of commercial Pt/C. FePc_electrolyte (liquid catalyst) exhibited a steady profile for chronoamperometry, and good diffusivity of lithium ions as measured from electrochemical impedance spectroscopy. The bifunctional catalysts when applied as electrocatalysts in non-aqueous lithium air batteries delivered better electrochemical performance mainly by reducing the large overpotential associated with ORR and OER. Both the cells with solid and soluble FePc exhibited better reversibility and cyclability. The performance of FePc catalyst as solid and liquid has been comparative analyzed in detail.

Lithium–air (O2) batteries still suffer from a relatively low practical energy density even though it far exceeds other energy storage systems with its extremely high theoretical energy density. The multiphase electrochemical reaction on the air–cathode of a Li–air battery has difficulty in proceeding when operated with solid catalysts. The battery reaction involves three-phase (solid–liquid–gas that is, catalyst–electrolyte–O2) electrochemical interface which landed in the investigation of a diffusive liquid phase electrocatalyst. Iron phthalocyanines (FePc) were dissolved in 1M LiTFSI (DMSO) electrolyte and employed as liquid catalysts in Li–air batteries. The dissolved FePc facilitated the cell reaction kinetics by acting as a transporter for superoxide species (O2)- and electrons between the cathode surface and discharge products, Li2O2. The electrochemical battery testing and impedance analyses exhibited better performance with liquid FePc catalysts than the solid catalysts. The proper formation and decomposition of Li2O2 without direct contact with carbon surface or blocking of pores were evident from the post characterization studies of the air cathode surfaces. Figure 1

Li-air batteries are appealing as they offer much higher energy density than the current Li-ion batteries. However, the non–aqueous Li-air batteries suffer from poor cycle life due to electrolyte decomposition and clogging of the air electrode by insoluble discharge products. Efficient bifunctional catalysts could lower the overpotential and improve the stability of Li-air batteries, thus prolonging its cycle life. This study focuses on Iron phthalocyanines (FePc) supported on carbon materials as a solid electrocatalyst for lithium air batteries. Metal phthalocyanines were utilized mainly because of their structural analogy which could be fine- tuned by the metal being used, accessibility, and low cost. The carbon supports such as reduced graphene oxide (rGO) and carbon nanotubes (CNT) were utilized which rendered desirable surface properties like high surface area and high electronic conductivity. FePc/carbons delivered superior electrocatalytic performance for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) comparable and better than that of commercial Pt/C. The bifunctional catalysts were then applied as electrocatalysts in non-aqueous lithium air batteries. The air cells delivered better electrochemical performance mainly by reducing the large overpotential associated with ORR and OER. The cells exhibited better reversibility and cyclability as well. The improved electrocatalytic activity was mainly because of the π–π interaction between carbons and iron phthalocyanines. In addition, the effects of ball milling by ball milling the FePc, and the effects of nitrogen (N2) doping by doping the carbon supports with N2 were investigated. Ball milling has significantly improved the electrocatalytic properties of FePc and N2 doping further enhanced the overall performance.

The increased concern for energy storage technology leads many scientists to have interests in the development of new conceptual batteries. Among many storage devices, lithium air batteries are attractive because they are compact, light weight and cost-effective and, more to the point, employ a lighter air cathode operating on environmentally abundant oxygen. Despite the high energy density of lithium air batteries, current lithium air battery system presents many challenges, like limited electrical efficiency which is due to the overpotential or polarization losses at the cathode during discharge and charge. Current Li–air batteries can only be discharged–charged at a current density of 0.1–0.5 mA cm2 and the voltage gap between the charge and discharge is larger than 1.0 V, which results in a low voltage efficiency of Recently we have investigated improved electrocatalytic activity of carbon materials by nitrogen doping. After nitrogen doping all the carbon materials exhibit increase in surface area, which is basic requirement for cathode materials of lithium oxygen batteries. All the nitrogen doped carbons show the positive peak potential than undoped carbon materials and as well as the electron transfer number calculated for the nitrogen doped carbons are closed to the commercial Pt/C which attributed to the improved performance of carbon materials by nitrogen doping[1]. On the other hand Manganese oxides (MnOx) have been widely studied as an alternative to Pt-based catalysts because of their many advantages, such as abundance, low cost, environmental friendliness, and acceptable activity. We have investigated the performance of α and δ-MnO2 with various different nanostructures as cathode catalyst in lithium air batteries. α-MnO2 shows the best capacity retention and 100% efficiency in comparison with δ-MnO2. [2] Although α-MnO2 is believed to be a promising bi-functional catalyst for ORR and OER. Nevertheless, it is evident that the bifunctional activity of α-MnO2 still falls below those of Pt-based catalysts. Therefore, in order to enhance the catalytic activity of α-MnO2 nanostructures, silver nanoparticles have been deposited over the α-MnO2 nanorods by a simple hydrothermal assisted Polyol method. Silver exhibits similar electrocatalytic activity as that of platinum which is also comparatively cheaper and abundant. We have optimized the deposited ratio of silver nanoparticles on α-MnO2 nanorods. The silver deposited MnO2 materials exhibit improved cycleability with reduced voltage gap than bare MnO2 nanorods throughout the cycle life of lithium air battery. In order to improve further catalytic activity of MnO2 nanomaterials, currently we are working on different morphologies of α-MnO2-RuO2 composites as well as MnO2/N-doped Carbon composites. Addition of ruthenium in the α-MnO2 has significantly improved the OER activity of the composite which results in the reduction of charge potential. On the other hand α-MnO2/N-doped carbon composite shows the best capacity retention and stable cycling even after 50 cycles. Other physical and electrocatalytic studies are under investigation. In this presentation, we will mainly introduce some of promising results from α-MnO2-RuO2 and MnO2/N-doped Carbon composites works. Our findings add to our understanding of non-precious catalysts and further development of low-cost and high-efficiency alkaline polymer electrolyte fuel cells and metal-air batteries. [1] Awan Zahoor, Ho Saeng Jang, Jeong Sook Jeong, Maria Christy, Yun Ju Hwang, Kee Suk Nahm, Applied Catalysis B: Environmental, 147, 633-641 (2014). [2] Awan Zahoor, Ho Saeng Jang, Jeong Sook Jeong, Maria Christy, Yun Ju Hwang, Kee Suk Nahm, RSC Adv., 2014, 4, 8973.