bluuebunny/crossref_metadata_2025 huggingface dataset:
IR Study on Room Temperature Atomic Layer Deposition of Aluminum Nitride Using Plasma Excited Ammonia
Authors: Saito Kentaro , Yoshida Kazuki , Miura Masanori , Kanomata Kensaku , Ahmmad Bashir , Kubota Shigeru , Hirose Fumihiko
Published: May 2020

Aluminum nitride (AlN) has been attracting much attention since it has a wide direct transition band gap of 6.3 eV and it is applicable for UV-LEDs. The AlN films have been deposited by chemical vapor deposition (CVD) and atomic layer deposition (ALD). These conventional processes were performed at a temperature of 300 °C and higher. To apply the AlN coating on flexible films, the low temperature deposition process has been demanded. To demonstrate the AlN deposition at RT, an RT-ALD of AlN using trimethylaluminum (TMA) as an Al precursor and plasma-excited ammonia are studied based on study on multiple internal reflection infrared spectroscopy (MIR-IRAS).

An n-type Si substrate was used as a prism for MIR-IRAS. The size of prism was 10×45 mm2 and its resistivity was 1000 Ωcm. 45° bevels on each of the short edges were formed. The prism was set in a reaction chamber for the ALD. If the IR spectra before and after the processes are defined as Ir and I0, respectively, we can calculate the absorbance (Abs) from the equation, Abs = log10(Ir/I0). TMA was used as the Al precursor. In the nitridation step, ammonia and argon was mixed with a volume ratio of 7:3, followed by being excited through a quartz tube with an RF power of 250 W and a frequency of 13.56 MHz. The flow rate of the mixed gas was 10 sccm. Ammonia molecules in the mixture were dissociated to NH radicals and some fragments. Plasma excited ammonia was provided in the chamber.

We observed the surface reaction to confirm TMA adsorption and examine if the plasma-excited ammonia generated nitride on the TMA adsorbed surfaces. Fig. 1 shows IR spectra were obtained from a TMA adsorbed surface with exposures from 1000 to 400000 L at RT. Peaks at 2933, 2894, and 2829 cm-1 correspond to C-H vibrations in TMA. The positive peak indicates that the TMA was adsorbed on the surface at RT. Fig. 2 shows IR spectra measured from plasma excited ammonia treated TMA saturated surface. Negative peaks at 2933, 2894, and 2829 cm-1 suggests that the nitride was generated there at RT. We also confirmed the presence of AlN on the prism by an Al 2p peak at 73.3 eV and a N 1s peak at 398.1 eV by X-ray photoelectron spectroscopy. These suggests that it is possible to deposit AlN at RT.

Figure 1
Transparent and Stretchable Supercapacitors Based on PEDOT:PSS/Nano-Metal Oxide Composite Electrodes
Authors: Feng Wei , Chen Han-Yi , Huang Jin-Hua
Published: May 2020

Owing to advances in technology, people focus more on electronic devices that are both aesthetic and functional. Therefore, stretchable and transparent electronic devices have been widely used in wearable devices, transparent displays, and other fields. In the meanwhile, stretchable and transparent energy storage devices are developed to support those electronic devices. Therefore, this study aims to fabricate stretchable and transparent supercapacitors with high electrochemical performance.

Conductive polymer poly(3,4-ethylene dioxythiophene) (PEDOT) doped with poly(styrene sulfonate) (PSS) is a promising candidate for the transparent electrode of supercapacitors as it is highly transparent, stretchable and provides well electrochemical performance. However, the PEDOT:PSS electrode suffers from low capacitance. This study focus on combining PEDOT:PSS with nano-metal oxides as hybrid electrodes. All-solid-state asymmetric supercapacitors assembled with those hybrid electrodes and gel electrolyte are highly transparent, stretchable and possess superior electrochemical performance. This research demonstrates the great potential of highly stretchable and robust all-solid-state asymmetric supercapacitor based on PEDOT:PSS/nano-metal oxide composite electrodes.
Novel Method for Detection of Organic Additives in Copper Plating Baths
Authors: Huang Jhih-Jie , Weng Yu-Ching
Published: May 2020

Appropriate organic additives, including accelerators, inhibitors and leveling additives, are essential in the copper plating process of printed circuit boards to achieve defect-free filling effect. The fluctuation of organic additives would cause product defects and reduce manufacturing efficiency resulting in increasing additional cost. Therefore, it is very important to control the quality of electroplating. Development of sensors that detect the concentration of organic additives is indispensable. At present, the concentration of organic additives can only be measured by offline sampling in industry. An indirect cyclic voltammetry stripping (CVS) are often used to detect the concentration of organic additives based on the stripping peak of copper. This study attempts to measure the organic additives directly at high applied potential by using three different electrochemical methods, including linear sweep voltammetry (LSV), differential pulse voltammetry (DPV) and square wave voltammetry (SWV). The results show that the response current values of the three electrochemical methods have a good linear relationship with the concentration of the organic additives. The sensitivity of the electrode by LSV is the highest. There are two proper potentials to detect the additives by SWV. However, the detection potentials of the three organic additives are quite close. If these organic additives should be accurately identified separately, the electrode would need to be further modified.
Free-Standing Poly (Acrylic) Acid / Potassium Hydroxide Based Polymer Electrolyte Membrane As Electrolyte for Printed Zinc/Silver Oxide Batteries
Authors: Singh Gaganjot , Katiyar Monica
Published: May 2020

Printable batteries have attracted great attention as an emerging power source for wearable electronics such as RFID tags, implantable medical devices etc. The need for environmentally friendly batteries with high energy density has led to the development of partially printed primary zinc-silver oxide batteries. It has been reported that printed Zn/Ag2O systems have low cost, lightweight and easy processing methods. A free-standing polymer membrane (FSM) made up of poly(acrylic) acid, poly(ethylene)oxide and potassium hydroxide has not been systematically studied for its application as an electrolyte in printed batteries. In this work, we have prepared and characterized FSM for its compatibility to be used as an electrolyte in a Zn/Ag2O systems by employing electrochemical, microscopic and spectroscopic techniques. Cyclic voltammetry is used to understand the electrochemical processes going on the electrode, charge-discharge curves are reported to present the specific capacity of the battery. For printed electrodes, ionic conductivity is of the order of 10-3 siemens.cm-1 transference number (Zn+), for Zn|| FSM||Zn (Printed zinc (Zn)) cell structure is 0.247.

Further, a comparative study of FSM behavior with printed zinc and the zinc metal foil electrodes is done with an intention to understand the electrochemical behaviour of zinc electrodes in Zn/Ag2O all-solid-state battery device. Specific capacities of 3.604 and 2.495 mAh.cm-2are achieved for batteries having zinc printed and metal foil electrodes respectively. Though printed electrodes demonstrated better specific capacity, its repeatability remains an issue. Further work is being done to address the issue of electrode recyclability and performance repeatability.
Vitamin-Based Organic Electrolytes for Redox Flow Batteries
Authors: Shi Raymond Rong Sheng , Lauw Sherman Jun Liang , Foo Nicolette Angelique Bao Yun , Webster Richard David
Published: May 2020

With the current drive towards environmental sustainability, electrochemical energy storage system (EES) such as redox flow batteries (RFB) are thought to be a promising solution as they can play an important role in balancing energy generation and consumption to ensure power network stability and reliability. [1,2] Organic compounds possess tremendous potential for energy storage as they are structural diverse and synthetically tunable. In addition, organic compounds can be cost-effective and environmentally benign due to their abundancy in nature. However, many organic species experience stability issue in their charged form. [3,4] The present study reports an all-organic vitamin-based molecular system based on a non-aqueous, mixed-reactant electrolyte containing modified forms of the naturally occurring vitamin K1 and vitamin E as anolyte and catholyte, respectively. [5,6] In the presence of malonic ester (a relatively weak organic acid), the redox transformations of the organic species were proven chemically stable and reversible under exhaustive electrolysis conditions, as confirmed by UV-vis spectroscopy. [7] The pairing of both half-cells provides a desirable experimental cell voltage of 1.27 V. The proposed system also demonstrates good thermal and ambient stability via series of experiments. The overall findings presented demonstrate the practical significance of the vitamin-based organic electrolytes in the all-organic RFB technologies.

References

1. S. H. Shin, S. H. Yun and S. H. Moon, RSC Adv, (3) 2013, 9095-9116.

2. X. Luo, J. Wang, M. Dooner and J. Clarke, Appl. Energy, (137) 2015, 511-536.

3. X. Wei, X. L.; Xu, W.; Huang, J. H.; Zhang, L; Walter, E.; Lawrence, C.; Vijayakumar, M.; Henderson, W. A.; Liu, T. B.; Cosimbescu, L.; Li, B.; Sprenkle, V; Wang, W. Chem. Int. Ed.
2015, 54, 8684 –8687.

4. X. Wei, X. L.; Pan, W. X.; Duan, W. T.; Hollas, A.; Yang, Z.; Li, B.; Nie, Z. M.; Liu, J.; Reed, D.; Wang, W.; Sprenkle, V. L. ACS Energy Lett. 2017, 2 (9), 2187-2204.

5. Y. L. Hui, E. L. K. Chng, Y. L. C. Chng, H. L. Poh and R. D. Webster, J. Am. Chem. Soc, (131) 2009, 1523-1534.

6. H. M. Peng, B. F. Choules, W. W. Yao, Z. Zhang, R. D. Webster and P. M. Gill, J. Phys. Chem B, (112) 2008, 10367–10374.

7. R. R. S. Shi, M. E. Tessensohn, S. J. L. Lauw, N. A. B. Y. Foo and R. D. Webster, Chem. Commun, (55) 2019, 2277.
Nitric Oxide Synthase-Based NO-Releasing Films for Improved Biocompatibility of Blood-Contacting Medical Devices
Authors: Maher Shaimaa , Kalil Haitham , Bayachou Mekki
Published: May 2020

Blood-contacting medical devices, such as vascular grafts, stents, heart valves, and catheters, are often used to treat cardiovascular diseases. These implantable medical devices, even if labeled as biocompatible, can cause serious complications in patients. Thrombus formation and infection are the main causes of failure of these devices. In contrast to the healthy endothelium, which actively resists thrombosis, artificial surfaces promote clotting through a complex series of interconnected processes that include protein adsorption, adhesion of platelet, leukocytes and red blood cells, ending with thrombosis.

Nitric oxide is an important intercellular and intracellular signal molecule that regulates the cardiovascular, nervous, and immune systems. It is generated from L-arginine by a family of enzymes, called nitric oxide synthases. Under physiological conditions, a constitutive Ca2+-dependent NOS in endothelial cells (eNOS) is responsible for the continuous release of NO. In addition to its role in vasodilation and regulation of vascular tone, continuous release of NO by the endothelium has also been shown to counteract the adhesion of platelets to the inner walls of blood vessels. From this standpoint, NO is a natural antithrombotic agent in blood vessels. In this regard, NO-releasing films as coatings on blood-contacting devices have shown the potential to be effective in preventing platelet adhesion, activation, and aggregation, therefore reducing the risk of thrombus formation on the treated surfaces.

In this project, we use layer-by-layer thin film building strategy to form layers of polyethyleneimine (PEI) and recombinant NOS as NO-releasing coatings. Charge-based Layer-by-layer electrostatic adsorption allows for assembly of multi-component protein/PEI films. When surfaces coated with PEI/NOS multilayered films are exposed to substrate arginine, a source of reducing equivalents, and other ingredients of the NOS reaction, nitric oxide is formed and released. In this work, we characterize the PEI/NOS thin films in terms of structure of NOS within the films as well as the amount of active NOS. Fourier transform infrared (FTIR) spectroscopic analysis was used to characterize structure-activity relationships of these NOS-containing thin films. We used cyclic voltammetry to determine the active enzyme concentration on the modified surfaces, and how this relates to enzymatic activity in terms of NO released fluxes from the thin films. Finally, we conduct platelet adhesion assays to determine if the amount of platelets adsorbed on the PEI/NOS films is affected by the amounts of NO released from these coatings.
Polymer Blends of Poly(ethylene oxide) and Phosphonium Ionenes As Solid Polymer Electrolyte Membranes for Lithium Ion Batteries
Authors: Callaway Jumia , Abdulahad Asem
Published: May 2020

Solid polymer electrolytes offer potential improvements to lithium ion batteries that include extending their operating temperature range and improving the safe use of the batteries by inhibiting lithium dendrite formation. Because solid polymer electrolytes replace traditional liquid electrolytes as the lithium ion transport medium and also act as the electrode separator, these materials must offer good ionic conductivity along with providing good interfacial contact with the electrode material. This work presents the synthesis and characterization of polymer blends comprised poly(ethylene oxide) and phosphonium ionenes. Ionenes are a class of polycation that includes positive charges within the polymer backbone. Because the positive charge is a part of the polymer chain, the spacing and distribution of these charges have a significant impact on the properties of ionenes. This research focuses on determining the role of charge spacing and distribution of charges along the backbone of phosphonium ionenes on their ability to transport lithium ions. To accomplish this, phosphonium ionenes are blended with low molecular weight poly(ethylene oxide) (e.g. less than 3,000 g/mol) at mass ratios of 20:1, 10:1, and 5:1. The resulting blended solid polymer electrolyte membranes are evaluated for their thermal, mechanical and electrochemical properties along with their charge/discharge performance in coin cell batteries. The dependence of phosphonium ionene structure as well as the composition of SPE blends will be presented.
Nanowire Organic Sensor for Ammonia Detection
Authors: Kilani Mohamed , Yu Xuecheng , Mao Guangzhao
Published: May 2020

Ammonia is one of the largest produced chemicals with a global production of 150 million tons in 2017, expected to increase 8% in the next 4 years. It is widely used in several industries mainly in fertilizers manufacturing, but also in refrigeration systems, production of plastics, and as intermediates for pharmaceuticals synthesis. However, ammonia is highly corrosive and can damage cells in the body in contact, posing serious health risks. Despite the developments made in the detection systems, ammonia is still one of the most dangerous substances, responsible for the second highest number of chemical exposure casualties. The current detection solutions have serious limitations to be broadly used in industrial safety. Detection systems can generally fall under two categories, high-end equipment that is expensive, not user-friendly and can be only used in lab settings, and affordable devices that is prone to false alarms in a varying environment (humidity, temperature, etc.).

In this presentation, we will talk about the Nanowire Organic Sensor technology as an alternative solution platform for ammonia monitoring that is affordable and can provide real-time and wide-area coverage. Our patented technology is a room-temperature process based on electrochemical deposition which facilitates scalable manufacturing directly on substrates and devices. Compared with the existing nanowire sensor fabrication methods, out innovation has four main unfair advantages. 1) By direct deposit of a solution droplet, nanowires are created right on chips or micro-fabricated devices. 2) It is a room temperature fabrication process, thus enabling less complex and capital-intensive manufacturing process. 3) It is a modular method that enables combinatory synthesis of a wide range of new organic nanowires. 4) It is a fabrication technology compatible with flexible electronics platforms. We will show how the combination of the sensor arrays, impedance spectroscopy and artificial neural networks model enhances the selectivity in varying levels of humidity. We will also talk about how the technology is compatible with the internet of things technology and cloud services, and how the combination could be leveraged to ensure more flexible monitoring of ammonia for industrial safety.

Keywords: Electrochemical deposition, chemical sensing, nanomanufacturing.
Study of Modified LiFePO4 Cathodes for Lithium-Ion Batteries
Authors: Doumbia Mohamed
Published: May 2020

The electrochemical performance of lithium iron phosphate cathodes is studied after the preparation of composite materials made with the addition of polyaniline and carbon nanofiber. These materials have an enhanced 3-D conducting network which we believe will improve electron mobility. Electrochemical measurements will be made to study the conductivity of the material. We posit that through increasing the cathode material’s electrical conductivity, a battery with high C-rate capability may be easily produced. Preliminary results show that these materials exhibit higher C-rate capability and improved cyclability when compared to pristine lithium iron phosphate cathodes.
Active and Stable Mxene Modified Cu2o Composite Films for Photoelectrochemical Water Splitting
Authors: Yilmaz Meltem , Handoko Albertus Denny , Anasori Babak , Seh Zhi Wei , Goh Gregory Kia Liang , Gogotsi Yury , Tang Junwang , Parkin Ivan P , Sankar Gopinathan
Published: May 2020

Although limited in supplies and non-renewable, fossil fuels currently provide 80% of the global annual energy.1 Furthermore, the combustion of fossil fuels emits lingering gas emissions that exacerbates global warming.

Unlike fossil fuels, the solar energy is abundant, globally accessible and renewable, therefore developing technologies which can efficiently and sustainably harness and utilise this energy source is imperative. Solar-driven water splitting has been one of the most studied reactions because its product (H2) is a clean energy source with 4-fold higher mass energy density than fossil based fuels like gasoline. However, achieving good solar to hydrogen conversion efficiency (STH) in a single device remains a big challenge.

Cu2O is a very attractive photocathode material for the solar-driven water splitting as it has a narrow direct band gap of ca. 2 eV, which is capable to absorb most of the visible portion of the sunlight. It has favourable band positions for the hydrogen evolution reaction, with a theoretical 18% STH efficiency.2 However, one major drawback which limits the wider use of this material is its lack of stability in aqueous solutions when exposed to light.

In this study, we aim to introduce MXene’s as a cocatalyst on to Cu2O films. MXene’s are a family of 2-dimensional transition metal carbides, nitrides and carbonitrides. They have good electronic conductivity, good chemical stability and abundant active sites,3 making them a suitable co-catalyst for solar-driven water splitting reactions.

We observed a 3.7-fold increase in photocurrent density during photoelectrochemical (PEC) measurements at 0 V (vs. reversible hydrogen electrode) on MXene modified Cu2O compared to the plain Cu2O film. We also found that MXene addition, along with deposition of ZnO charge transfer layer, significantly improves the photo-stability of Cu2O photocathodes during simulated solar-driven water splitting reactions. We attribute this outcome mainly to the enhancement of the interfacial charge transfer and electrode photoconductivity upon illumination imparted by MXenes.

References

1 World Energy Counc., 2013, 1–28.

2 A. Paracchino, V. Laporte, K. Sivula, M. Grätzel and E. Thimsen, Nat. Mater., 2011, 10, 456–461.

3 M. Naguib, M. Kurtoglu, V. Presser, J. Lu, J. Niu, M. Heon, L. Hultman, Y. Gogotsi and M. W. Barsoum, Adv. Mater., 2011, 23, 4248–4253.
High Throughput Experimental Technologies for Li-Ion Batteries
Authors: Huang Andy , Jiang Xiaoping
Published: May 2020

Next generation Lithium ion batteries materials with higher energy, lower cost, long lifetime, and better safety, require the investigation of unknown lithium-ion systems and a vast amount of experiments. Advanced cathode, anode and electrolyte materials discovery is one possible solution to the rapid optimization. In this work, MTI Corporation and MTI SZKJ’s effort on modify the existing technologies to develop a high throughput materials experimental line for Lithium-ion batteries materials research are reviewed and discussed.

The first step is high throughput, automatic dispensing of solid powders or liquid. Five powder or six liquid dispensing heads and balances, with one dispensing head for each material component, are integrated with a carousel type sample changer for automatic powder or liquid dispensing with varying ratios between different material components. The second step is high throughput ball milling of the as-dispensed powder samples. With 4 sets of 4 cavity milling jars, totally 16 parallel ball milling experiments of 10 g samples can be carried out in a planetary ball mill machine. The mixed powder samples are then high throughput pellet pressed by a 10 ton electric hydraulic press with a carrousel type sample changer. Next, a compact 16-channel tube furnace up to 1100 °C is employed for sintering, annealing, or quenching operations. Finally, the elemental compositions of bulk samples are high throughput analyzed by an X-ray fluorescence (XRF) scanning system for providing instant feedbacks to the synthesis / processing steps.

Keywords: Li-ion Batteries Materials Discovery, High Throughput

Figure 1
Tuning of D-Band Center of Platinum Nanoparticles By Changing Transition Metal Oxide Support Materials for Enhancement of Oxygen Reduction Reaction
Authors: Ando Fuma , Gunji Takao , Ohsaka Takeo , Matsumoto Futoshi
Published: May 2020

The enhancement of oxygen reduction reaction (ORR) on platinum nanoparticles (Pt NPs) was examined by changing transition metal oxide support for Pt NPs. In order to use transition metal oxide having low electron conductivity as electrocatalyst support materials, thin the transition metal oxides were formed on cup-stacked carbon nanotube (CSCNT). In addition, mixed transition metal oxides having various ratios of two transition metal ions were prepared to produce continuous changes in the electron state (d-band center) of Pt NPs. The ORR activity measured in an acidic aqueous solution depended on the kinds of the metal oxide supports. The plot of the d-band center of Pt NPs deposited on the metal oxides vs. their ORR activity showed a volcano shape. That is, the volcano plot could be drawn by changing the support materials for the first time and maximum ORR activity could be observed at an optimized level of the d-band center. The metal oxide of TiNbOx (Ti:Nb = 1:6.6) could produce the optimized d-band level and could reach the ORR activity to the maximum activity. It was made clear from X-ray photoelectron spectroscopy (XPS) measurements that the d-band center could be down-shifted moderately by donation of electron from the metal oxide supports to Pt NPs for enhancing the ORR.
Highly Stretchable PEDOT:PSS Organic Electrochemical Transistors Achieved Via Polyethylene Glycol Addition
Authors: Li Yang , Zhang Shiming , Li Xinda , Unnava Venkata Ramana Nitin , Cicoira Fabio
Published: May 2020

Organic electrochemical transistors (OECTs) are widely used in biosensing and bioelectronics, due to their ability to convert ionic into electronic signals and their high transconductance. Stretchable OECTs are particularly suited for on-skin and on-organ bioelectronics, since they are able to record or transmit signals under mechanical strain. Most stretchable OECTs are based on the conducting polymer poly(3, 4-ethylenedioxythiophene) doped with polystyrene sulfonate (PEDOT:PSS), which needs to be appropriately processed to yield stretchable films. Here we report stretchable OECTs that are obtained by modifying the mechanical properties of PEDOT:PSS films via the addition of low-molecular weight polyethylene glycol (PEG), which acts as a plasticizer. The presence of PEG in the films prevents the formation of cracks under strain while maintaining a high electrical conductivity, thus resulting in improved electromechanical properties. In particular, the additon of PEG leads to a higher channel thickness and increased ion mobility in the films, thus resulting in stretchable OECTs with high transconductance and fast response time. This work shows that high stretchability, high transconductance and fast repsonse time can be simultaneously obtained in OECTs, paving the way for their applications in conformable devices at the human-machine interface.
Active Sites of Zn Catalysts for CO2 Electroreduction to CO
Authors: Xiao Jing , Gao Minrui , Luo Jing-Li
Published: May 2020

Electrochemical CO2 reduction reaction (CO2RR) is an attractive strategy to mitigate CO2 emissions and enable the conversion of CO2 to valuable fuels. To date, noble metals, such as Ag, Au and Pd, have been reported as the benchmarking electrocatalysts to selectively convert CO2 to CO, but their scarcity and the associated high cost inevitably limit their large-scale applications. Zn holds the promise as a potential alternative to noble metals due to its earth-abundance and intrinsic selectivity for CO production. However, systematic studies that clarify the active sites of Zn catalysts for CO2RR are presently lacking in the literature. In response, density functional theory (DFT) calculations were used in this study to identify the active sites for CO2RR to CO based on a Zn50 model. The binding energies of the key intermediates for CO2RR and the competitive hydrogen evolution reaction (HER) on Zn(100) facet, Zn(002) facet, edge and corner sites were calculated. The Gibbs free energy diagrams for CO2RR and HER were then constructed based on the computational hydrogen electrode model. The results of this work that can guide further experiments to achieve highly efficient CO2RR over Zn-based catalysts.
Modification of Carbon Black by Thermal Decomposition of Lead Acetylacetonate to Improve Activities for Ethanol Oxidation at Supported Pt Catalysts
Authors: Hang Hui , Pickup Peter G
Published: May 2020

Direct ethanol fuel cells (DEFC) are a type of promising energy-conversion device with high efficiency. The investigation of anode catalysts for DEFC is extremely important in improving energy efficiency. Improvement of the catalytic activity and long-term stability of Pt catalysts supported on some metal oxides has been reported for ethanol oxidation in acidic conditions. This synergistic effect mainly arises from the bifunctional effect and charge transfer between metal oxides and Pt catalysts.[1]

In our study, thermal decomposition of Pb(acac)2 (acac = acetylecetonate) was used to rapidly prepare lead oxide supports on titanium foil and high surface area carbon electrode materials for electrocatalysis. On titanium electrodes, a thin layer of lead oxide was first prepared, followed by drop coating with a certain amount of a Pt nanoparticle solution. For high surface area carbon electrodes, Pt nanoparticles were adsorbed onto a carbon black-lead oxide composite, followed by painting a catalyst ink onto carbon fibre paper.

The catalysts were characterized by X-ray diffraction and energy dispersive X-ray spectrometry. The electrochemical performance of the catalysts for ethanol oxidation was studied through cyclic voltammetry, chronoamperometry and in a proton exchange membrane electrolysis cell. Durability was studied through investigating the composition change before and after performing cyclic voltammetry. The lead oxide support was found to have a significant influence on onset potential, current density and product distribution for ethanol oxidation.

Acknowledgments: This work was supported by the Natural Sciences and Engineering, Research Council of Canada and Memorial University.

[1] G.M. Alvarenga, H.M. Villullas, Current Opinion in Electrochemistry, 4, 39, (2017).
The Rational Design of Nanocarbon and Metal Composite Materials for Lithium–Sulfur Battery Cathode: Li- or S-Binding?
Authors: Chen Xiang , Zhang Qiang , Hou Tingzheng
Published: May 2020

Given the high theoretical capacity 1672 mAh g−1 of sulfur cathode, lithium–sulfur (Li–S) batteries have been intensively concerned to fulfill the urgent demands of high capacity energy storage. However, quite a few obstacles are still hindering the practical applications of Li–S batteries. One of the major issues is the complex diffusion of lithium polysulfide intermediates, which in combination with the subsequent paradox reactions is known as the shuttle effect. Heteroatom-doped carbon and polar compound additives are two promising routes in ascendant for the adsorption and immobilization of polysulfide intermediates.

In this work, a series of heteroatom-doped graphene nanoribbons (GNR) was modeled and their binding behaviors toward both polar lithium polysulfide and nonpolar elemental sulfur were evaluated. The first-principle calculation was conducted to systematically describe the complex interactions in terms of different doping atoms. By meticulously analyzing the configuration, binding energy, bond length, charge transfer, and deformation charge density, how the doping atoms including B, N, O, F, P, S, and Cl affect the adsorption of sulfur and Li2Sx species was explored. The local polarization of binding sites within the carbon lattice was correlated to the subsequent dipole–dipole interactions, both of which were considered to play critical role in the system. A set of principle rules and a volcano plot correlating the electronegativity of doping atoms to the adsorption energies were proposed to guide the future screening and design of scaffolding materials with chemical dopants.

Besides doped carbon hosts, various metal composites have been considered as additives to enhance the binding effects and promoting the conversion of high-order polysulfides. The first-row transition-metal sulfides (TMSs) are selected as the model system to obtain a general principle for the rational design of a sulfur cathode. The strong S-binding that is induced by charge transfer between transition-metal atoms in TMS slabs and S atoms in Li2S is confirmed to be of great significance in TMS composite cathodes. An analogous periodic law of anchoring strength was find in 3D-metal sulfide system, which can be extended well to the 3D-metal oxide system well, and VS was predicted to be an excellent polar host candidate for sulfur cathodes. This finding provides a general and practical principle for rational design of advanced sulfur cathode materials, which is expected to be an effective toolbox to screen composite sulfur cathode for Li–S batteries with high energy density and long cycle life.

References:

[1] X. Chen, H.-J. Peng, R. Zhang, T.-Z. Hou, J.-Q. Huang, B. Li, Q. Zhang, ACS Energy Lett.
2017, 2, 795−801.

[2] T.-Z. Hou, X. Chen, H.-J. Peng, J.-Q. Huang, B.-Q. Li, Q. Zhang, B. Li, Small
2016, 12, 3283−3291.

[3] T.-Z. Hou, W.-T. Xu, X. Chen, H.-J. Peng, J.-Q. Huang, Q. Zhang, Angew. Chem. Int. Ed.
2017, 56, 8178−8182.
Lithium Polysulfide-Based Electrolytes for Li Metal Anodes
Authors: Zhao Chen-Zi , Huang Jia-Qi , Zhang Qiang
Published: May 2020

Li metal batteries (such as lithium–sulfur (Li–S) and lithium-air batteries) have been strongly considered as the promising candidates for the next-generation energy storage devices. Unfortunately, as the result of the notorious Li dendrite growth inherent in these batteries (upon repeated charge/discharge cycling), the concomitant serious safety concerns and low Coulombic efficiency have retarded their practical applications. Herein, we report a facile but effective strategy to in-situ construct a stable and compact solid electrolyte interphase (SEI) layer to protect Li deposits by the synergetic effect of Li2S5-based ternary-salt (LiTFSI–LiNO3–Li2S5) electrolyte. LiTFSI affords a high Li conductivity of the electrolyte in a working battery. The reactions between LiNO3 and Li2S5 induce Li2SO3 formation, which is favorable to build protective SEI layer. Compared with routine LiTFSI mono-salt electrolyte, the Li2S5-based ternary-salt electrolyte renders Li metal anode (1) dendrite-free morphology, (2) improved Coulombic efficiency (94% compared with 60% in routine electrolyte), (3) suppressed polarization, and (4) prolonged lifespan (80 h compared with 20 h). These superior characteristics are attributed to the enhanced stability of the SEI layer by deliberately introducing the Li2S5 polysulfide as a pre-existing precursor, which, however, is always considered as an undesirable intermediate in Li–S batteries. Further development of this electrolyte enables practical applications for rechargeable lithium metal batteries, especially Li–S batteries.

References

[1] C. Z. Zhao, X. B. Cheng, R. Zhang et al.
Energy Storage Mater. 2016, 3, 77.

[2] C. Z. Zhao and Q. Zhang. Trends in Chem. 2019, 1, 709.

[3] X. B. Cheng, C. Z. Zhao, Y. X. Yao et al.
Chem. 2019, 5, 74.

[4] L. P. Hou, H. Yuan, C. Z. Zhao et al.
Energy Storage Mater. 2019, DOI: 10.1016/j.ensm.2019.09.037.

[5] G. Zhang, H. J. Peng, C. Z. Zhao et al.
Angew. Chem. Int. Ed. 2018, 57, 16732.
Characterization of Formic Acid Oxidation at Surface-Modified Pt/C Catalysts
Authors: Akther Jasmeen , Pickup Peter G
Published: May 2020

Over the last several decades, much attention has been given to low temperature fuel cells which provide energy based on electrochemical oxidation of fuels such as hydrogen and small organic molecules. Many researchers in the field of fuel cell technology have been focusing on the development of cost effective and durable catalysts. Among the small organic fuel molecules, electrochemical study of formic acid oxidation is being intensively investigated for two main reasons; formic acid can be used as a fuel in direct formic acid fuel cells and it can serve as a model reaction that can be used to understand more complex oxidation reactions, such as the oxidation of methanol and ethanol.

Platinum is one of the most commonly used and effective catalysts for the oxidation of small organic molecules, despite the fact that it has significant disadvantages, such as high cost and loss of performance due to extreme susceptibility to poisoning by CO. To solve these problems several techniques have been applied, most of which are based on modifying the bulk and/or surface of Pt by a second metal. Heterogeneous bimetallic catalysts often show significantly enhanced catalytic performances because of their improved electronic and chemical properties that are different from their parent metals. Bimetallic catalysts provide opportunities to significantly improved catalytic selectivity, activity and durability.

In order to improve the electrochemical oxidation of formic acid, addition of second metals such as Ru, Pb, Os, Sn, Cu, Pd, Rh, Bi has been widely applied. Among them, bismuth especially has received much attention as a Pt surface modifier. Various structures such as PtBi alloy, PtBi intermetallic, and surface modified systems have been reported. Co-deposited, carbon supported PtBi/C [1], under potential deposition [2] and irreversibly absorbed [3] Bi modified Pt surfaces were reported to be good catalysts for formic acid oxidation, in terms of onset potential, activity as well as stability and durability.

The primary objective of this research is to obtain mechanistic information on the oxidation of formic acid, methanol and ethanol by comparing the effects of various modifying metals on voltammetric data at surface-modified Pt/C catalysts. For example, Bi was found to greatly enhance oxidation of formic acid through the direct pathway in which absorbed CO is not formed, while it strongly inhibits methanol oxidation. Data for Pb and Rh modified Pt will also be presented.

References:

1. X. Yu and P.G. Pickup, Electrochimica Acta, 56, 4037-4043, (2011)

2. S. Kang, J. Lee, J.K. Lee, S.Y. Chung and Y. Tak, The Journal of Physical Chemistry B,
110, 7270-7274, (2006)

3. J.B. Kim, K. Kwon, C.K. Rhee, J. Han and T.H. Lim, Electrochimica Acta,
53, 7744-7750, (2006)
Synthesis of Mixed Phase nanoTiO2 particles & Their Application in Photocatalytic Water Decontamination
Authors: Chalastara Konstantina , Demopoulos George P.
Published: May 2020

A green, sustainable hydrolytic precipitation process is used to synthesize different blends of intrinsically heterostructured (mixed phase) titanium dioxide (TiO2) nanoparticles (NPs). NPs are evaluated for the decontamination of organic and inorganic pollutants. The NPs are characterized for their morphological, semiconductor and photocatalytic properties. As organic compound, methyl orange was used to evaluate the mixed phase TiO2 NPs through adsorption and photo-oxidation, while selenium (IV and VI) species were the inorganic pollutants of interest, removed by adsorption and photo-reduction. A comparative assessment of photocatalytic effectiveness of different nanoTiO2 varieties is presented revealing contrasting behavior between organic and inorganic removal, while exemplifying the importance of tuning phase composition, as per intended application.
A Novel Biomass Derived Interconnected Nanosheets Porous Carbon from Withered Rose Derived as Inexpensive and Sustainable Energy Material for Advanced Supercapacitor Application
Authors: Khan Abrar
Published: May 2020

The porous carbons derived from bio-mass precursors for energy storage devices have

been gained increased research attention due to their cost effectiveness, easy way to fabrication, ecofriendly nature and more sustainability. Carbon derived from biomass is more favorable electrode material for supercapacitor. In the recent work we successfully prepared interconnected nanosheets porous carbon from withered rose by facile, post treatment, pre carbonization, acid washing and activation process. This rose-derived active carbon nanosheets (RDPC) display a high specific surface area (1980m2g-1) with a small pores after activation process. RDPC exhibit the electrochemical properties of the prepared porous carbon were analyzed by 3-electrode configuration with 6 M KOH electrolyte. It is implies that the porous carbon exhibited the high specific capacitances of 350 F g-1 at 1 A g-1, and 165 F g-1 at 150 A g-1. Besides, the porous carbon can be achieved an excellent long-cycling life with only loss 2.7% of its initial capacitance over 1,20,000 cycles even at 150 A g-1. The observed very attractive electrochemical behavior of the new biomass porous carbon derived from tea waste will be a competitive candidate as cathode material in the development of high-performance and green supercapacitor for advanced energy storage devices.

Figure 1
(Invited) Can Phosphorus-Doped Graphene be a Good Anode for Na-Ion Batteries? A First-Principles Study
Authors: Paek Eunsu
Published: May 2020

Secondary energy storage technologies based on sodium ions are an important emerging alternative to lithium ion batteries (LIBs). Sodium is less expensive than lithium, with its supplies being much wider and more democratically distributed throughout the globe. There are fundamental physical differences between Na and Li, and it is clear the knowledge available from extensive research on LIBs does not translate to sodium. However, the understanding of Na-based systems is at their infancy, and their complexities are just beginning to be understood. In this talk, we theoretically investigated the possibility of using phosphorus-doped (P-doped) graphene as an anode material in sodium ion batteries (NIBs). We reveal some fundamental physical properties of sodium adsorption on P-doped graphene by calculating formation and adsorption energies, voltage vs. capacity curves, migration for Na transport, and electron density of states and mobility. Our calculations suggest that Na adsorption on the same side of protrudent P is the preferred configuration for application in NIBs. This particular configuration possesses very large Na capacity (~582 mAh/g). More importantly, Na has to cross a diffusion barrier (~0.3 eV) and it diffuses in a zigzag path on the P-doped structures due to the presence of protrudent P with larger atomic size compared with the size of a carbon. We will also present electronic movements and accumulations during sodiation. Though carrier mobility may be not as fast as in metals or pristine graphene because P-doped graphene with Na adsorbed on it becomes a semiconductor, the calculated carrier mobility is still significantly large with the order of 103 to 105 cm2/V/s. Lastly, we will discuss the guidelines for the efficient design of P-doped graphene as a promising anode for NIBs.
Immobilization of Multi-Carbonyl Molecules on High Surface Area Carbon for Energy Storage Applications
Authors: Delaporte Nicolas , L. Belanger Rachel , Lajoie Gilles , Trudeau Michel , Zaghib Karim
Published: May 2020

The synthesis of diamino-aryl-1,4,5,8-naphtalenetetra-carboxylic diimide molecule (NTCDA-(aryl-NH2)2) was reported. This molecule was characterized by elemental analysis, SEM, IR and TGA. A organic Li-ion electrode with NTCDA-(aryl-NH2)2 as active material was tested and a reversible behavior was observed with a multiple electrons process delivering about 100 mAh.g-1 at an average potential of 2.45 V vs. Li/Li+. In parallel, the diazotization study of this molecule was investigated with a three-electrode assembly. Then, the electrochemical reduction of freshly formed NTCDA-(aryl-N2
+)2 ions was followed by cyclic voltammetry experiments. An irreversible cathodic wave at around 0.0 V vs. Ag/AgNO3 that is associated to the reduction of the in-situ generated NTCDA-(aryl-N2
+)2 ions was observed. The blocking effect of the grafted layer deposited on the glassy carbon surface was verified with ferrocene as a redox probe. Finally, the immobilization of this molecule on Ketjen black carbon powder by spontaneous reduction of freshly formed NTCDA-(aryl-N2
+)2 ions was realized in a one-pot reaction. The redox-active carbon with a loading of grafted groups estimated between 26.4 and 36.7 wt. %, depending of the method of modification, cycled at high rate for thousands of cycles.
Development of Waste Red-Mud Nanoparticle Decorated Laser-Induced Graphene Flexible Sueprcapacitor
Authors: Bhattacharya Gourav , Fishlock Sam Jeffery , Roy Susanta Sinha , McLaughlin James
Published: May 2020

Environmental benign, inexpensive, flexible, smart energy storage micro-supercapacitors, with high energy and power densities and long-term cyclic stability are appealing for next generation energy storage devices. Conventionally, highly conducting carbon-based nanomaterials with high-surface areas are extensively used as supercapacitor electrode and the introduction of metal oxides (or conducting polymers) induces pseudocapacitance and can further enhances the specific capacitance and energy density. Red mud (RM), an aluminum industry waste by-product which is a rich source of hematite phase Fe2O3. RM is environmentally hazardous due to its alkalinity and is produced at an annual rate of ~ 110 million tonnes each year, much of which is not well utilized, and left to lie in large lakes; thus, methods of finding value-added applications for RM are well sought after. In this study, we used mechanical milling to produce uniform spherical RM nanoparticles and utilized these in a flexible micro-supercapacitor device. The as-synthesized nanoparticles were decorated over a laser induced porous 3D graphene (LIG) on a polyimide substrate. The composite electrode material was characterized using transmission electron microscopy (TEM), field effect scanning electron microscopy (FESEM), X-ray photo electron spectroscopy (XPS), Raman spectroscopy and cyclic voltammetry (CV). A solid-state ionic liquid based polymer gel electrolyte was produced using a mixture of ionic liquids {[EMI][TFSI] and [EMIM][BF4]} and a PVDF polymer. Inkjet printing technique was employed to produce the silver current collector and the as fabricated inter-digitated micro-supercapacitor device (Figure 1a) exhibited an areal capacitance of 203 mF cm-2 with a higher potential window of 2.7 V, high energy density of 0.018 mW h/cm2 at 0.66 mW/ cm2 power density. RM decoration increased the energy density of the device by 3.7 fold compared with pristine LIG device (Figure 1b). Rapid lateral ion flow in the planar architecture, presence of metal oxides (mostly hematite), higher electrochemically active surface area, better charge transfer kinetics were shown to yield improvements in the energy-density and the electrochemical performance of the device. An in-depth electrochemical study also revealed that the charge storage mechanism was governed by diffusion driven pseudocapacitance. The device exhibited good robustness and could resist bending and flexing and the prototype device exhibited to power a white-light LED (Figure 1c). Overall, this work demonstrates that RM may be used as a low-cost pseudocapacitive element in supercapacitor electrodes and aid in reducing the environmental impact of the aluminium production cycle by recycling this abundant waste product.

Figure 1
Incorporation of Carbon Nanotubes in Silicone Matrices to Improve Wave Energy Converters Performance’s
Authors: Sylvestre Alain , Zhao Hang , Fan Benhui , Jean-Mistral Claire , Bai Jinbo
Published: May 2020

The marine energies constitute a strategic sector of the renewable energies to diversify and complete the energy mix. At present, offshore wind energy and the marine turbines are the main approaches. In stages of more upstream research, demonstrators of wave energy converters (WEC) based on a hydraulic conversion have difficulty in developing because of problems of reliability. The harnessing of this field of wave energy could find a new impetus thanks to the development of concepts in break based on innovative and economically technologies: electroactive polymers (EAP). Based on the distortion of an EAP which plays the double role to get the wave energy and to convert it in electrical energy, these generators open interesting perspectives of development because they free themselves from mechanical absorber at the origin of numerous failures of the WEC.

Among challenges identified for the realization of performant EAP-WEC, the availability of more successful materials to convert the mechanical energy is at the heart of the concerns. Starting from carbon nanotubes nano-object to end in a viable mechanical structure, we have developed methods and processes which will be implemented in the future technologies of the wave energy but also aim at the manufacture of a functional prototype of laboratory.

Our strategy is based on the incorporation of nano/micro hybrid reinforcements of carbon nanotubes within a silicone matrix in order to realize (i) flexible conductive electrodes and (ii) to improve the properties of the active material. A parylene coating of carbon nanotubes has demonstrated to reduce percolation and thus an improvement of the dielectric strength of the active silicone matrix. Finally, mechanical – electrical conversion is undoubtedly improved by this approach as confirmed by mechanical tests, dielectric spectroscopy and dielectric strength.

Acknowledgements : The authors thankfully the national French program ANR SEASEA for funding.