bluuebunny/crossref_metadata_2025 huggingface dataset:
Nano-Sized Iron Oxide Material for Sodium Ion Batteries
Authors: Liu Wen , Zhou Luozeng , Wang Yong , Li Yong , Shi Bin , Guo Rui , Pei Haijuan , Xie Jingying
Published: February 2020

In lithium ion batteries, iron oxide as one transition metal oxide is an excellent electrode material, possessing high lithium stroge capacity, low cost, abundant reserves, environmental-friendly[1-3]. However, iron oxide suffers from poor electrical conductivity and large volumetric expansion during cycling. Accordingly, the researchers seek many atrategies to improve the cyclability and structure stability [4-5].

In this work, iron oxide with a size of about 100 nm (inset in Fig. 1) was employed in sodium ion batteries. Furthermore, binder-free, self-standing iron oxide film electrodes were prepared by vacuum filtration method using chemically obtained graphene oxide sheets (GO), electric conductor (super P) and iron oxide powder. Iron oxide film electrode delivers an initial discharge capacity of 1116.8 mAh g-1 and exhibit an initial Coulombic efficiency of 66.7% at the rate of 0.02C. The cycle performance was shown in Fig. 1. The capacity fades rapidly in the first 5 cycles, then fades laggardly in the subsequent cycles, with a stable capacity of 519.9 mAh/g after 40 cycles.

Fig.1 The cycle performance of iron oxides in sodium ion batteries at 0.02C. The inset is the SEM of iron oxide.

This work was supported by Shanghai Sailing Program (18YF1417000).

Reference
s
:

[1] L. Zhang, H. B. Wu, S. Madhavi, et al. J. Am. Chem. Soc. 134, 2012, 17388.

[2] B. Wang, J. S. Chen, H. B. Wu, et al. J. Am. Chem. Soc. 133, 2011, 17146.

[3] B. Wang, G. Wang, H. Wang. Electrochim. Acta, 156, 2015, 1.

[4] X. Cao, B. Zheng, X. Rui, et al. Angewandte Chemie, 53,2014, 1404.

[5] W. Xiao, Z. Wang, H. Guo, et al. J. Alloy & Compound, 560, 2013, 208.

Figure 1
(Invited) X-Ray Absorption Spectroscopy: Investigations of Catalysis and Batteries at APS Beamline 9-BM
Authors: Wu Tianpin
Published: February 2020

As a beamline dedicated to the X-ray Absorption Spectroscopy, 9-BM is capable to cover very wide energy range (2145.5 eV P-K edge to 24350 eV Pd-K edge). In recent years more efforts have been devoted to the fields of catalysis and energy storage, focusing on catalysis for efficient conversion of energy resources into usable forms, and storage of such energy in efficient and safe capacitors. To understand and predict how catalysts and/or energy storage materials function, it’s very important to characterize the materials under actual reaction conditions (in-situ or operando). 9-BM has leveraged the advanced capabilities for in-situ catalysis and electrochemistry, as well as the ability to collect high quality spectroscopy data at a rapid rate (Quick EXAFS). Scientists using 9-BM are able to gain unique insight to how chemical processes affect and are affected by the materials under investigation. In this talk, the capabilities will be displayed with a few examples of the science enabled by them.
(Invited) Opportunities and Challenges for in-Situ Synchrotron Characterization of All Solid State Batteries
Authors: Hatzell Kelsey B. , Dixit Marm
Published: February 2020

The increasing demand for portable electronics, stationary storage, and electric vehicles is driving innovation in high-energy density batteries. Solid electrolytes that are strong enough to impede lithium dendrite growth may enable energy dense lithium metal anodes. Currently, the power densities of all-solid state batteries is limited because of ineffective ion transport and chemical and physical decomposition at solid|solid interfaces. Solid electrolytes consist of both intrinsic interfaces formed by grains, vacancies, and material junctions and extrinsic interfaces formed at solid|solid interfaces. The former involves transport between two ion conducting phases, and the latter involves ionic transport between an ion conducting phase and a mixed ion and electron conducting phase. The nature of ionic transport at intrinsic and extrinsic interfaces is important for mitigating chemical and structural instabilities. Extrinsic interface instabilities are responsible for high interfacial resistances. Examples of extrinsic interface instabilities include: (1) chemical decomposition and the formation of a solid electrolyte interphase at the electrode|electrolyte interface, (2) regions of excess and deficient lithium content, and (3) poor or delaminating-type contact at the interface which can contribute to non-uniform current distributions and localized degradation. In order to displace liquid electrolytes, new materials and engineering strategies need to be developed to negate these degradation pathways. New insight into the governing physics that occurs at these interfaces are critical for developing engineering strategies for the next generation of energy dense batteries [1,2]. However, buried solid|solid interfaces are notoriously difficult to observe with traditional bench-top and lab-scale experiments. In this talk I discuss opportunities for tracking phenomena and mechanisms in all solid state batteries in-situ using advanced synchrotron techniques. Synchrotron techniques that combine reciprocal and real space techniques are best equipped to track relevant phenomena with adequate spatial and temporal resolutions.

[1] Shen, Fengyu, Marm B. Dixit, Xianghui Xiao, and Kelsey B. Hatzell. "Effect of pore connectivity on Li dendrite propagation within LLZO electrolytes observed with synchrotron X-ray tomography." ACS Energy Letters 3, no. 4 (2018): 1056-1061.

[2] Dixit, Marm B., Matthew Regala, Fengyu Shen, Xianghui Xiao, and Kelsey B. Hatzell. "Tortuosity Effects in Garnet-Type Li7La3Zr2O12 Solid Electrolytes." ACS applied materials & interfaces 11, no. 2 (2018): 2022-2030.
Bayesian Optimization Guided Coarse-Grained Molecular Dynamics for Designing Highly Conductive Solid Polymer Electrolytes
Authors: Wang Yanming , Xie Tian , France-Lanord Arthur , Berkley Arthur , Johnson Jeremiah A. , Shao-Horn Yang , Grossman Jeffrey C.
Published: February 2020

Solid polymer electrolytes (SPEs) are promising building blocks for the next-generation lithium-ion batteries, due to their unique advantages in safety, cost and flexibility. However, the incorporation of current SPEs into real-world applications is largely limited by their low ionic conductivity, which motivates the innovation and development of highly conductive SPE materials. Here we develop a computational materials exploration approach that combines the Bayesian Optimization (BO) algorithm with coarse-grained molecular dynamics (CGMD) simulations. While the CGMD effectively reduces the computational cost in comparison with the fully atomistic models, it reasonably maintains the capability of capturing the ion motions and the polymer conformational evolution. Also, we utilize the CGMD input parameters, including the particle sizes and the intermolecular interaction strengths, as universal and interpretable descriptors, to construct a continuous CG design space that encodes the information from the conventional chemical species space. Adopting the BO algorithm, we conduct efficient explorations of this high-dimensional CG space iteratively, towards achieving complete descriptions of the correlations between the molecular level information and the transport properties. The trained CGMD-BO model predicts the conductivities for several commonly used polymer electrolyte systems, all in good agreement with the experimental measurements. In addition, the model suggests new directions to improve upon existing electrolytes, by showing the dependences of the lithium conductivity on the properties of anions, secondary sites, and backbone chains, respectively. This research improves our understanding of the ion transport mechanisms in polymers, as well as provides a new tool for designing tailored SPE materials.
All-Solid-State Organic/Inorganic Composite Polymer Electrolyte with Enhanced Ionic Conductivity Performance
Authors: Wang Jiali , Zhang Xiaoqiang , Cui Yixiu , Zhao Yu , Wei Su , Cui Yanhua
Published: February 2020

Polymer electrolyte has been attracted ever-increasing attentions in the field of in all-solid-state lithium-ion batteries. But the low ionic conductivity at ambient temperature and poor mechanical strength hinder its broad applications. Based on the extensive literature reading and fundamental experiments, we have proposed Methyl 2-hydroxyethyl cellulose(HEMC) as the organic filler to enhance PEO-based polymer electrolyte. Thus we have obtained a kind of flexible and superior all-solid-state polymer electrolyte. Herein, we discuss the enhancement on ionic conductivity reinforced by active inorganic fillers-Li6.4La3Zr1.4Ta0.6O12 (LLZTO). The obtained flexible and all-solid-state polymer organic/inorganic composite polymer electrolyte with high conductivity at ambient temperature, good mechanical strength, wide electrochemical window and super stability to anode lithium. Also, we have investigated the fundamental mechanism of organic/inorganic composite polymer electrolyte. There is a threshold in the process of reinforcing polymer electrolyte on ionic conductivity by active inorganic fillers. The conductivity is dominated by polymer base when it’s below the optimal value, and vice versa. It provides distinctive solutions and illumination for designing and fabrication of practical all-solid-state electrolyte.

Figure 1
Mitigating Interfacial Issues in All-Solid-State Li Battery By Using a Polymer-Solid-Electrolyte-Incorporated Composite Electrode
Authors: Jung Kyu-Nam , Shin Hyun-Seop , Lee Jong-Won
Published: February 2020

All-solid-state-batteries (ASSBs) provide technical solution to address the challenges of high safety and high energy density for future energy storage. However, their practical applications have been mainly hindered by the interfacial issues, since it is very challenging to construct intimate contact between the solid electrode and electrolyte due to their rigidity in conventional ASSBs, which leads to high polarization and low utilization of active materials. Herein, we demonstrate a simple but effective interfacial engineering approach to mitigate the poor interfacial contact via incorporating deformable polymer solid electrolyte (PSE) into the composite electrode. For the purpose, the poly(ethylene glycol)-based PSE was directly casted on and thermally infiltrated into the composite cathode (LiFePO4). From the various physicochemical and microstructural analyses, it was found that PSE exhibits the moderate Li+ conductivity (~ 6.6 × 10-4 S cm-1 at 65 oC) and wide electrochemical window (~ 4.5 V vs. Li/Li+), and its rheological properties are strongly dependent on the temperature. It was also observed that micro-pores in the composite electrode are completely filled without any cracking and the active components are fully covered by the deformable PSE. The cells assembled with PSE-incorporated cathode clearly exhibited the superior storage capacity, rate-capability and cyclablity in comparison with the pristine composite electrode. Moreover, 10 V-class bipolar ASSB (~10 mAh) comprising three unit cells connected in series was designed and constructed by using PSE-incorporated cathode, and its stable electrochemical performance was also demonstrated. Those results suggest that the PSE-infiltration process is considerably helpful for promoting the Li+ transport in the composite electrode by establishing intimate contacts between the solid electrolyte and active materials, and continuous ionic path through the whole composite electrode.
Mesoscale Chemomechanical Interplay of the LiNi0.8Co0.15Al0.05O2 Cathode in Solid-State Polymer Batteries
Authors: Besli Muenir Mustafa , Kuppan Saravanan , Metzger Michael , Shukla Alpesh Khushalchand , Christensen Jake , Doeff Marca , Liu Yijin
Published: February 2020

Presently, the challenges faced by batteries are twofold. Firstly, they are expected to possess high energy and power density for powering zero emission electric vehicles. Secondly, they are also expected to be inexpensive and safe for deployment in electric vehicles and consumer applications. A potential candidate ideally suited for this case are solid-state polymer lithium-ion batteries coupled with layered nickel-rich oxides such as LiNi0.8Co0.15Al0.05O2 (NCA) or LiNi1−x−yCoxMnyO2 (NCM). Replacing the non-aqueous, liquid electrolytic solution that is comprised of flammable components, with a solid-state electrolyte such as an inexpensive polymer is highly advantageous. However, layered nickel-rich oxides such as NCA are not only known for their high reversible capacity, but also their inherent structural and thermal instability at charged state, which leads to several degradation mechanisms including intergranular cracking. While this phenomenon has been studied extensively for lithium-ion batteries consisting of a non-aqueous, liquid electrolyte, it has not been studied for solid polymer batteries.

Secondary NCA particles harvested from cycled NCA-poly(ethylene oxide) batteries were subjected to a combination of two- and three-dimensional full-field transmission X-ray microscopy (2D/3D-FF-TXM) and high resolution broad ion beam- and focuses ion beam milling-scanning electron microscopy (BIB-/FIB-SEM). Doing so, the complex chemomechanical interplay within the hierarchically structured lithium-ion battery was investigated to reveal morphological defects and chemical heterogeneity in the secondary particles. Intergranular cracking was found to be extremely apparent after only a few cycles. It was found, that the absence of liquid electrolyte severely affects transport in fractured particles and may also hastens and accelerates fracture due to lower uniformity in current density. Intergranular cracks significantly increase diffusion path lengths of both charge carriers, electrons and lithium ions. While in liquid lithium-ion batteries, electrolyte filling the cracks should maintain lithium ion transport pathways but not electron transport pathways, in solid-state batteries, intergranular cracking compromises not only the electronic pathways, but also the ionic pathways. Eventually, intergranular cracking in polymer batteries seems to lead to isolated and inactivated primary grains within the core of secondary particles.

Figure 1
Effect of in-Situ Developed Carbon Derived from Waste As Efficient Supportive Electrocatalyst for Electrochemical Applications
Authors: Mir Rameez Ahmad , Pandey O. P.
Published: February 2020

The environmental and energy utilization issues are increasing day by day due to overuse of fossil fuels. The need of clean and efficient energy sources are of high demand. Meanwhile the energy density and fast charging and durable energy storage devices are being searched and fabricated. Hydrogen (H2) produced form water through electrochemical water splitting is considered as the principal renewable and ecofriendly energy source. The electrochemical water splitting via hydrogen evolution reaction (HER) is of great importance and research interest. The commercialization of HER is still a prevailing challenge. The search new catalysts of high efficiency with low cost to replace noble metal catalysts is need of the day. In this category molybdenum carbide (Mo2C) is one, which shows efficient performance towards HER in both acidic and basic medium. Thus the synthesis of low cost carbon coated Mo2C at nanoscale is highly desirable. The nature and amount of carbon over Mo2C enhances the electrochemical characteristics. The waste material utilization for its synthesis will further make the process more economical. In the present study, a new path to synthesize carbon coated Mo­2C nano powders utilizing carbon wastes as carbon source in specially designed autoclave at low temperature. The environmental issues caused due to disposal of these wastes will be addressed. The HER activity of Mo2C was studied in acidic medium 0.5M H2SO4 via three electrode setup with glassy carbon electrode (GCE), graphite rod and reversible hydrogen electrode (RHE) as working, counter and reference electrodes, respectively. The as synthesized product showed efficient HER results and higher cyclic stability. Moreover, the double layer capacitance (Cdl) characteristics reveal the synthesized material as suitable electrode candidate for storage applications.
Role of Alloying Elements on the Secondary Passivation of Ni-Cr Based Alloys
Authors: Ter-Ovanessian Benoît , Zhang Zhiheng , Marcelin Sabrina , Normand Bernard
Published: February 2020

At high anodic potentials, two phenomena may generally occur on the surface of a passivated electrode: the oxygen evolution and the transpassive dissolution (at grain boundaries or generalized). For some materials, this anodic dissolution is postponed by the structural or chemical modification of the passive film. This phenomenon is characterized by a second plateau on anodic polarization curves. This latter informs about a limited further dissolution. This feature is commonly called the secondary passivation.

Generally, it is assumed that the passive film grown on Ni-Cr based alloys is mainly composed of chromium (Ⅲ) oxide. However, in certain circumstances, the formation of oxide with higher valence of chromium is related to the secondary passivation. It is of interest to investigate the role of alloying elements in the process of the secondary passivation to solve industrial applications or alloys design issues.

The aim of the present work is to study the electrochemical behaviour, especially the secondary passivation behaviour, of different Ni-Cr based alloys and pure Cr. This was mainly achieved by using successive electrochemical impedance spectroscopy (EIS) measurements. After 24h of immersion in borate buffer solution, EIS diagrams for different samples were successively recorded at different potentials from cathodic to anodic direction on a wide potential range. The step-by-step polarization curves (potentiostatic polarization) obtained from successive electrochemical impedance measurements was used as a complementary method to conventional polarization curves.

Besides, each impedance diagram was firstly analysed by enhanced graphical representation and complex capacitance representation to assess electrolyte resistance, constant phase element (CPE) parameters (α and Q), capacitance and thickness of the passive film. Since in most of the cases the CPE behavior observed for passive films could be attributed to a distribution of the resistivity through the film thickness. The power law model was used to adjust the experimental impedance diagrams. This model allows to study the trend of the resistivity profiles within the passive film as a function of the potential. Thus, the variation of the determined parameters related to the potential was presented for the different alloys. The use of this analytical approach in the secondary passivation domain was discussed.

To conclude, the role of the alloying elements on the process of the secondary passivation and especially on the chemical composition of the passive film was discussed.
Passivation Behavior of Friction Stir Welded 304L SS in Thin Layer Electrolyte
Authors: Kundu Arnab , Korjenic Alen , Raja Krishnan S. , Charit Indrajit , Jana Saumyadeep , Darsell Jens
Published: February 2020

Friction stir welding (FSW) is being considered as a potential repair welding technique for nuclear spent fuel dry storage canisters. The heat affected zones (HAZ) of the fusion welded regions of the canisters become prone to stress corrosion cracking (SCC) due to chlorides in the environment. Pitting corrosion is usually observed in the welded regions which is the precursor for SCC. The goal of the present work is to understand the effect of chloride on the atmospheric corrosion behavior of FSW 304L stainless steel. A simulated crack was introduced into hot rolled and annealed 304L plates by electric discharge machining, and FSW was performed at two different temperatures, 725 and 825 °C in order to repair the simulated crack. Figure 1(a)-(c) shows the optical images of the 825 °C FSWed 304L alloy.

Electrochemical corrosion tests are being performed on FSWed 304L alloy in 3.5 wt% NaCl aqueous solution at 20 OC as a thin-layer electrolyte. A comparison will be made between the corrosion behaviors of the base metal, HAZ region and the weld nugget region for both FSWed specimen types. The electrochemical tests are carried out in an in-house designed electrochemical cell with less than 10 ml of electrolyte and variable electrolyte thicknesses in the range of 0.5 – 2 mm. Open circuit potential, cyclic polarization and potentiostatic tests at different passivation potentials are being conducted to understand the pit initiation and growth events as a function of FSW microstructures. Electrochemical impedance spectroscopy and Mott-Schottky analysis are carried out to understand the semiconducting properties of the passive film and their correlation with the passive film breakdown. This presentation will discuss the effect of FSW microstructures on the passivity breakdown in thin electrolytes containing chloride ions, and the results will be compared with that of tests conducted in the conventional bulk electrolyte arrangement.

Figure 1
Protective Coating on Aluminum Alloy Created By Combined Solvothermal and Chemical Methods: Corrosion Test
Authors: Baruah Bharat , Poyraz Altug Suleyman
Published: February 2020

This work demonstrate an in-situ solvothermal deposition of zirconium based metal-organic framework (MOF), UiO-66 derivatives on aluminum alloy. Such protection remarkably enhance the corrosion resistance and hydrophobic properties of the aluminum alloy. The observed corrosion resistance of the fabricated film was attributed to the resistant nature of the UiO-66 coating created on the alloy surface. SEM, FTIR, and XRD techniques were used to understand the microstructure and crystal structure of the designed composite materials. Electrochemical impedance spectroscopy (EIS) was used to assess the surface impedance.
Corrosion Potential Measurement to Investigate Copper Dissolution in Simulated Pore Environment on Ant Nest Corrosion
Authors: Honda Keisuke , Hoshi Yoshinao , Shitanda Isao , Itagaki Masayuki , Kumagai Kengo , Ito Shinnichi , Hosogi Tetsuro
Published: February 2020

Refrigerant leakage due to the occurrence of formicary corrosion, also called ant nest corrosion, has been serious problem in copper piping used for the heat exchangers 1, 2). Because the ant nest corrosion begins at small pit and progresses rapidly in the depth direction, it is difficult to detect the occurrence of the ant nest corrosion. Notoya 2) reported that the progress of the ant nest corrosion in the depth direction was related to the repetition of the proportional reaction composed of copper and divalent carboxylic acid copper complex. In the present study, the corrosion potential measurement was performed to investigate the influence of proportional reaction composed of copper and divalent copper ions on the progress of the ant nest corrosion.

A silicon sheet and two copper plates were used to simulate the pore environment on the ant nest corrosion. The small hole was drilled on the silicon sheet and copper plates. The diameter of the holes was 1 mm. The silicon sheet was sandwiched between copper plates, and the small hole penetrated into the silicon sheet and coper plates. This hole, which simulates the pore on ant nest corrosion, was filled with an aqueous solution of 100 ppm formic acid. In this case, the upper and lower copper plates were defined as working electrode 1 and 2 (WE1 and WE2), respectively. The corrosion potential measurement of the WE2 was carried out during the galvanostatic polarization of the WE1. A phosphor-deoxidized copper plates were used as the WE1 and WE2, and the electrochemical measurement was performed by a four-electrode system using a dual potentiostat.

The corrosion potential of the WE2 was measured during the applying the constant current of 20 μA to the WE1. The corrosion potential of WE2 was shifted to noble potential because of the dissolution of the divalent copper ions on the WE1. This implies that the cathodic reaction rate of WE2 was increased due to the increase of the divalent copper ions concentration near the electrode interface of WE2, leading to the repetition of the proportional reaction composed of copper and divalent copper ions.

References:

[1] S. Yamauchi, K. Nagata, S. Sato, M. Shimono, Sumitomo light metal technical reports, 52, 1-7 (1984).

[2] T. Notoya, T. Hamamoto, K. Kawano, Sumitomo light metal technical reports, 30, 123-128 (1989).
Meso-Structure Controlled Synthesis of Sodium Iron-Manganese Oxides for Na-Ion Batteries
Authors: Hirsh Hayley S , Zhang Minghao , Chung Hyeseung , Li Yixuan , Meng Ying Shirley
Published: February 2020

Increasing deployment of large scale electric storage applications would benefit from the development of inexpensive batteries. Na-ion batteries (NIBs) are of great interest since their cathodes can be made from inexpensive and abundant materials such as sodium, iron, and manganese. However, existing iron and manganese oxide cathodes lack the electrochemical performance, including capacity retention, required for these NIB applications and significant improvement is needed.

Prior work on lithium ion battery cathodes demonstrates that meso-structured materials can improve electrochemical performance for batteries. Incorporating spherical meso-structured materials in lithium ion battery cathodes was shown to improve capacity retention. To emulate this approach in NIB cathode materials, a synthesis method for producing pure phase spherical meso-structured sodium iron manganese oxide is first needed. No literature has been found that describes a method for this synthesis. Key synthesis parameters to be controlled include the choice of method, material precursors, pH of reaction, calcination time, and cooling rate.

In this work we demonstrate a modified co-precipitation method to synthesize spherical meso-structure pure phase P2-Na0.67Fe1/4Mn3/4O2 (see Figure 1) and we report initial characterization of the electrochemical performance of this material. The key parameter found to control the formation of a spherical meso-structure is the cooling rate applied during synthesis. The slow cooled material forms spherical meso-structures while the quenched material has no ordered meso-structure. Additionally, the spherical meso-structured material shows increased capacity, improved cyclability, and reduced polarization. The electrochemical performance enhancement is attributed to higher surface area, reduced surface concentration of sodium carbonate, and lower internal resistance during cycling. Further exploring the synthesis and mechanisms of meso-structured materials offers a path for improving Na-ion battery cathodes.

Figure 1
Study of Redox and Pseudocapacitive Processes of K-Ion Storage Using New Transition Metal Oxides Derived from PBA Type-Materials
Authors: Guzmán Vargas Ariel , Vazquez Juvencio , Acevedo-Peña Prospero , Martínez Ortiz María de J.
Published: February 2020

The fast growing use of natural energy sources such as solar and wind to generate electricity, requires the development of reliable, affordable, and efficient electric energy storage systems [1]. Thus, electrochemical capacitor systems can offer excellent devices showing high power (>10 kW kg-1), high rate capability and long cycle life (>1 000 000 cycles) [2]. Many kind of materials have been widely investigated as supercapacitor electrodes, such as carbon materials, graphene-based composites of metal hydroxides and metal oxides. In this work, new pseudocapacitive materials were obtained by thermal descomposition of cyanometalates (PBAs) obtained by precipitation over different carbon structures (graphene oxide, carbon nanotubes and mesoporous carbon). The materials were characterized using XRD, Raman, ATR-FTIR, SEM, TEM and XPS. Furthermore, the electrochemical performance of the materials was tested by cyclic voltammetry, step potential electrochemical spectroscopy, electrochemical impedance spectroscopy and charge-discharge curves at different current rates in 1 M KOH. These techniques were applied in order to understand the double layer and pseudocapacitive mechanism of K ion storage. The material formed in presence of graphene oxide exhibited the best electrochemical behavior, maintaining almost constant its initial capacitance after 500 cycles at 1 A g-1.

References

1. Yang, J. Zhang, M. C.W. Kintner-Meyer, X. Lu, D. Choi, J. P. Lemmon, J. Liu, Electrochemical Energy Storage for Green Grid. Chem. Rev., 2011, 111, 3577-3613.

2. S. Aric, P. Bruce, B. Scrosati, J.-M. Tarascon, W. V. Schalkwijk, Nanostructured materials for advanced energy conversion and storage devices. Nat. Mater., 2005, 4, 366 – 377.
Fundamental Chemistry behind Rechargeable Lithium Ion Batteries: An Ab Inito Study
Authors: Awasthi Shalini , Widanage Widanalage Dhammika
Published: February 2020

In recent years, due to increase in global energy demand, developing energy storage systems with higher energy densities are an urgent need. Rechargeable Li-ion batteries (LIBs) emerge as an important power sources for energy storage device for portable electronics and are being continuously investigated and developed for use in automobile electric vehicles (EV). However, during the cycling of LIBs, due to the decomposition of electrolyte, a passivation layer called solid electrolyte interphase (SEI) is formed on electrode surface. Although, SEI formation is vital in LIBs for long term performance, it leads to irreversible loss of lithium and thus, storage capacity of battery. While several studies have been performed in the past few decades on SEI, it is difficult to control its formation and growth, as the chemical composition, and stability of SEI depend on a list of factors. These factors include the electrode material, electrolyte composition, electrochemical conditions, and cell temperature. The perfect SEI would be a fast forming, flexible, stable, and contains insoluble species with low electronic and high ionic conductivity. Thus, the formation of SEI and the electrochemical stability of SEI components should be a primary topic of investigation in future development of LIBs.

To understand the stability and chemistry of SEI layer, density function theory based molecular dynamics simulations were performed. We used metadynamics to understand various degradation pathways of electrolyte decomposition in LIBs in various reaction conditions as well as in presence of additives. Car-Parrinello molecular dynamics based simulations were performed to determine the solvation structure of Lithium ion in presence of additives. Fig (1) shows the structure of solvation shell of Lithium ion (Yellow color code) in Ethylene Carbonate (EC). EC molecules in the first solvation shell is shown by ball and stick model. For the purpose of clarity Hydrogen atoms are not shown in EC molecules. color code: Lithium-Yellow, Oxygen-Red, Carbon-Grey.

Figure 1
Nanostructured Cobalt Oxide Directly Grown on Carbon Cloth for High-Capacity Lithium-Ion Battery Electrodes
Authors: Yoon Hyunseok , Song Hee Jo , Kim Dong-Wan
Published: February 2020

Nowadays, with the breakthrough development of various smart devices and electric vehicles that require a large power supply, rechargeable lithium-ion batteries are the most attractive energy storage system because of their high energy density and long lifetime by low self-discharge rate and no memory effect [1,2]. However, due to ever-increasing demands for rechargeable batteries with higher energy density, it is necessary to develop suitable electrode materials to satisfy the sufficient capacity and energy density required for large-scale energy storage systems [3]. As a commercial lithium-ion battery anode, graphite is widely used due to its low operating potential and high stability. However, it cannot fulfill the considerable demands of large-scale energy storage owing to its low practical capacity. As alternatives, transition metal (TM; Mn, Fe, Co and Ni) oxides have attracted great attention due to their high capacity. In this work, we develop the cobalt oxide (Co3O4) with attractively nanostructured architectures (nanowire, nanosheet) directly grown on carbon cloth substrate by a facile hydrothermal reaction followed by heat treatment process. For this, first, Co(NO3)2 and urea are dissolved in deionized water, and then carbon cloth is immersed in the solution. During the hydrothermal reaction, Co2(OH)2CO3·xH2O nanowires or Co2(OH)2CO3 nanosheets are grown on carbon cloth at 90 or 120 °C, respectively. After thermal treatment at 350 °C for 1 h in furnace, Co3O4 nanowires or nanosheets can be obtained. When tested as anodes for LIBs, as-fabricated electrodes without any conductive agents and polymeric binders exhibit high specific capacity because of their large specific surface area and enough space to buffer the volume change during conversion reaction. Therefore, it is considered that these high-performance electrodes can be used as high-capacity anodes for large-scale energy storage system.

References

[1] H. J. Song, D. S. Kim, J. C. Kim, S. H. Hong, D. W. Kim, J. Mater. Chem. A. 5 (2017) 5502–5510.

[2] Y. Yao, Y. Zhu, S. Zhao, J. Shen, X. Yang, C. Li, ACS Appl. Energy Mater. 1 (2018) 1239−1251.

[3] R. Hu, H. Zhang, Y. Bu, H. Zhang, B. Zhao, C. Yang, Electrochim. Acta 228 (2017) 241–250.
Parameters Identification of Solar Cell Batteries
Authors: Achaibou Nadia
Published: February 2020

Photovoltaics and wind energy cause instability of power grid due to their out put fluctuations. Battery energy storage system (BESS) is the current and typical means of smoothing solar power generation fluctuations. This paper will initially present a review of the several battery models used for battery energy storage system applications. Models will be discussed which takes into account the non-linear characteristics of the battery with respect to the battery’s state of charge. We identified the parameters of solar cell batteries using the method “parameter estimation tool” of simulink library. The selected mathematical models are the Macomber model and Thevenin model. In order to validate models, a comparison between results gotten by calculation with those by experimental data found by testing these batteries under different constant currents has been undertaken. This method allows us to know and predict the behavior of the battery in the applications of photovoltaic solar energy.

We note easily that the correlation between measured data and those calculated by the Macomber and Thevenin models for ambient temperature of 25 °C is good and very encouraging, so these models have been chosen for the survey of photovoltaic system simulation.
Identification of Battery State of Health By Combining Machine Learning and Impedance Spectroscopy
Authors: Tang Qiaochu , Zhang Yunwei , Lee Alpha , Stimming Ulrich
Published: February 2020

The possibility of diagnosing Li-ion battery’s state of health (SoH) and remaining useful life from electrochemical impedance spectra (EIS) using Machine Learning is investigated. The Gaussian Process (GP) with automatic relevance determination is used to identify degradation patterns without relying on any equivalent circuit models. The experiment consists of continuous charge-discharge cycling of commercial Li-ion coin cells. With the GP model trained with the entire spectrum measured on identical cells cycled under the same condition, the cycle number of a testing cell can be predicted by providing the corresponding EIS data. The trained GP model selected one frequency that is most indicative for the battery degradation, indicating the potential that the battery SoH can be diagnosed by measuring impedance at certain frequencies instead of taking a full-range EIS. Moreover, the GP model trained with all sets of data is able to identify the cycle number without knowing temperature or SoC, showing the possibility of developing a universal diagnosis methodology for battery management systems.

[1] R. R. Richardson, M. A. Osborne, D. A. Howey,
J. Power Sources
, Vol. 357, 31 Jul. 2017, pp209-219

[2] M. Galeotti, L. Cina, C. Giammanco, S. Cordiner, A. D. Carlo,
Energy
, 89 (2015) 678-686

Figure 1
Silica-Based Ionogels Deposited By Spray Coating for All-Solid-State Lithium-Ion Microbatteries
Authors: Hartmann Korina , Calberg Cédric , Paez Martinez Carlos , Heinrichs Benoît
Published: February 2020

The emerging market of the Internet of Things, smart objects and others increase the demand for micro energy sources. Rechargeable Li-ion batteries are a well-known technology for energy storage. However, safety issues and high production costs constrain progress. Research on solid electrolytes, such as LiPON, was performed to evade leakage. But LiPON suffers from low ionic conductivity and a cost and time intensive production process. Another approach is the substitution of volatile and flammable organic electrolyte solvents with ionic liquids (IL), which display negligible vapor pressure and wide chemical, electrochemical, and thermal stability. Electrolyte solution based on ILs can be confined into inorganic porous networks forming so-called ionogels (IG), which are investigated as solid electrolyte materials. IGs combine low hazard and good ionic conductivity [1].

Silica-based IGs compatible with Li/LiCoO2 systems were prepared in a one-pot sol-gel process. The composition of the IG precursor solution and the influence of trifluoroacetic acid as catalyst were studied to obtain a fast condensation. Homogeneous and transparent IGs were obtained with a gelation time of less than 12 h. The physical properties of the host matrix were characterized by N2 sorption and SEM.

The silica host matrix is a 3D network predominantly built from 3-fold condensed silicon centres. Its structure changes from densely packed silica particles to open porous architecture.

The electrochemical performances of the IG deposited by spray coating under ambient contitions were evaluated by impedance spectroscopy measurements. First results show that these promising IGs may be successfully used as electrolyte in Li/LiCoO2 cells, with ionic conductivities up to 0.15 mScm-1. The coin cell batteries prepared with our IGs did not show dendritic growth after more than 100 cycles of galvanostatic cycling at a C/4 rate.
Study on Water Swellable Enzyme-Polymer Conjugate for Biosensor
Authors: Chung Yongjin , Ji Jungyeon , Kwon Yongchai
Published: February 2020

Water swellable enzyme-polymer conjugate prepared by polyacrylic acid and glucose oxidase(PAA-GOx) is suggested to enhance a performance of biosensor. According to results, PAA-GOx shows better electrochemical performance although the amount of enzyme in biocatalyst using polyethyleneimine and graphene oxide composite(PEI-GO) is lower than that of glutaraldehyde-GOx(GA-GOx) conjugate. The catalytic activity and sensitivity are 98.0 μA cm-2 with 20mM of glucose in PBS solution and 6.9 μA cm-2 mM-1, which are ca. 10 times higher value compare to GA-GOx due to its high swellability in water. Due to the reason, PAA-GOx conjugate show an excellent ability to absorb water based electrolyte and cause high response and sensitivity through smooth mass transfer of glucose substrate to active site of enzyme. Moreover, the long term stability of catalyst is also improved due to the amide bonds prepared by carboxylic acid of PAA and amine of GOx and PEI.

This was supported by Korea National University of Transportation in 2019
(Invited) Electrocatalytic N2 Reduction to NH3 Using the Enzyme Nitrogenase
Authors: Seefeldt Lance C , Badalyan Artavazd , Yang Zhi-yong
Published: February 2020

The reduction of dinitrogen (N2) to ammonia (NH3) is an important reaction that supports all of life and many industrial processes. An enzyme found in bacteria called nitrogenase catalyzes this reaction under mild conditions. We are unravelling the mechanism of N2 reduction catalyzed by nitrogenase by studying the purified enzyme. One of the most interesting aspects of mechanism involves the delivery of electrons to the enzyme to support the N2 reduction reaction. Using mediated electrocatalysis, we have developed a system that allows electron delivery to nitrogenase to be achieved, revealing the rate limiting chemistry of the enzyme. This system allows the flow of electrons into nitrogenase to be quantified under different conditions to answer key mechanistic questions. For example, this system has been used to measure the rate of electron delivery to nitrogenase as a function of the concentration of substrate, N2. It is shown that the electron delivery rate is constant across the N2 concentration up to 1 atm partial pressure. This finding clarifies a confusion in the literature where earlier work suggested that the rate of electron delivery through nitrogenase decreased by 40% as the partial pressure of N2 increased up to 1 atm. The electrocatalytic system is now being used to reveal different aspects of the catalytic mechanism of nitrogenase.

Figure 1
Surface Recognition and Electron Transfer in Electroactive Bacterial Biofilms: Principal Component Analysis
Authors: Lebedev Nikolai , Yates Matthew , Griva Igor , Tender Leonard M.
Published: February 2020

Bacterial electroactive biofilms attract researchers’ attention due to their ability for generation of electric current when electrons travel for very long, up to several tens microns, distance. It was demonstrated that this electron transfer ability correlates with the accumulation in the BF a c-type cytochrome (Cyt), but molecular nature of this Cyt, its spatial localization, interaction with the environment, regulation and the controlling factors are not understood. Bacterial cell polarity is an internal cell asymmetry that correlates with the cell ability to sense energy and metabolite sources, chemical signals, quorum signals, toxins, and movement in the desired directions. This ability also plays central role in cell attachment to various surfaces and biofilm formation. In the present work, we develop a new experimental approach for analyzing redox potential spatial distribution within individual bacterial cells and use this approach for identification how attachment to inorganic mineral, mica affects redox state inside individual G. sulfurreducens cells. The approach is based on confocal Raman microscopy allowing for precise estimation of redox state and localization of subcellular cytochromes. Applying Gaussian deconvolution and principal component analysis we are able to identify spectral signatures of cytochromes in different redox states and intracellular locations. Our results give a new tool for quick identification of internal and surface exposed cytochromes and their localization at bacterial cell sides facing the substrate and the solution. They open up the possibility for analyzing electrochemical potentials inside individual bacterial cells and indicate that Cyt redox state might be a driving force switching cell metabolic activity that leads to irreversible cell attachment to electrode, cell-to-cell association, and biofilm formation.

Nikolai Lebedev, Matthew Yates, Igor Griva, and Leonard M Tender: Internal Polarity of G. Sulfurreducens Bacterial Cells attached to an Inorganic Substrate. ChemPhysChem 19:1–11, 2018

Nikolai Lebedev, Igor Griva, Anders Blom and Leonard M. Tender Effect of iron doping on protein molecular conductance. - Physical Chemistry Chemical Physics 20: 14072-14081, 2018
Enhanced Osteogenic Differentiation of Human Mesenchymal Stem Cells on Ti Surfaces with Electrochemical Nanopattern Formation
Authors: Kim Doohun
Published: February 2020

To increase bone regeneration around a titanium implant, nanopattern surfaces with 10 nm nanopores in 120 nm dimples were produced by electrochemical nanopattern formation (ENF). The ENF surfaces were obtained by removing the TiO2 nanotube layers prepared by an anodization process. To determine the effect of the ENF surface in vitro, cell proliferation assays, alkaline phosphatase (ALP) activity assays, Alizarin red staining, western blotting, and immunocytochemistry were performed. Atomic force microscopy and scanning electron microscopy analysis showed that the ENF surface had an ultrafine surface roughness with highly aligned nanoporous morphology. In vitro, human mesenchymal stem cells exhibited increased cell proliferation and enhanced expression of osteogenic molecules such as ALP, osteopontin, and osteocalcin on ENF surfaces compared to the TiO2 nanotube surfaces. Therefore, ENF is a promising technique for coating osteointegrative implant materials.
Noble Metal Free Molecular Based Anode for H2-O2 Fuel Cell
Authors: Reuillard Bertrand , Coutard Nathan , Artero Vincent
Published: February 2020

The implementation of hydrogen as a sustainable energy vector relies on the efficient production and oxidation of H2 at low cost using electrolysers and fuel cells, respectively.[1] The hydrogen oxidation reaction (HOR) at the anode of state-of-the-art fuel cell is performed by catalysts based on rare and expensive platinum metal, making these fuel cells less suitable for industrial applications.[2] Hydrogenases (H2ase) enzymes are the only known catalysts able to compete with Pt for the HOR with turnover frequencies up to 10000 s-1 thanks to the complex environment of the active site.[3] These H2ases are also known for their sensitivity to a large number of inhibitors such as CO, H2S and O2 and can show limited stability over time.

In order to carry out H2 oxidation there are only a few examples of molecular catalysts able to perform this reaction near the thermodynamic potential with high turnover frequencies. They all belong to the family of Ni-based diphosphine complexes bearing integrated proton relays (Ni(P2N2)2), originally developed by the group of D. L. DuBois.[4] These bio-inspired catalysts have been immobilized onto carbon electrode surfaces and showed efficient H2 production and oxidation properties under acidic aqueous conditions.[5,6]

More recently, the modification of the outer coordination sphere of these Ni based catalysts with arginine (Ni(P2NArg2)2) moieties showed drastic improvement in the electrocatalytic HOR performance in homogeneous conditions. The immobilization of this catalyst onto a carbon nanotube modified electrode gave rise to high current densities for HOR, up to 20 mA cm-2.[7] We will show how the elaboration of porous nano-structures led to further increased performance of the molecular based anode.

The research leading to these results has received funding from the Fuel Cells and Hydrogen 2 Joint Undertaking under grant agreement No 779366. This Joint Undertaking receives support from the European Union’s Horizon 2020 research and innovation programme, Hydrogen Europe and Hydrogen Europe research.

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Semi-Artificial Photosynthetic Tandem Systems
Authors: Zhang Jenny Z
Published: February 2020

The emerging field of semi-artificial photosynthesis aims to combine the strengths of materials chemistry with biology to explore novel pathways for solar-to-chemical conversion. Here, I will describe the wiring of the water oxidation enzyme, photosystem II (PSII), to high surface area electrodes, thus allowing for electrons extracted from the first step of photosynthesis to be better harnessed for driving solar fuel conversion reactions and for interrogating enzyme functionality. I will focus on recently developed semi-artificial Z-schemes that rationally combines synthetic light harvesters with PSII to utilise more of the solar spectrum and achieve bias-free solar fuel production. These include tandem systems that utilise a p-Si based photocathode, and another that utilises a dye-sensitised PSII photoanode.