bluuebunny/crossref_metadata_2025 huggingface dataset:
Sulfurized-Polyacrylonitrile Cathode with Polyacrylic Acid Binder and Fluoroethylene Carbonate Additive for Improved Performances of Lithium-Sulfur Batteries
Authors: Kim Hee Min , Aurbach Doron , Sun Yang-Kook
Published: February 2020

Sulfurized carbonized polyacrylonitrile (S-CPAN) is a promising cathode material for Li−S batteries owing to the absence of polysulfide dissolution phenomena in the electrolyte solutions and thus the lack of a detrimental shuttle mechanism.1,2 However, challenges remain in achieving high performance at practical loading because of large volume expansion of S-CPAN electrodes and lithium anode degradation at high current densities. To take advantage of the unique charge-discharge mechanisms of S-CPAN electrodes at high sulfur loadings, we introduce a novel cell design through the application of polyacrylic acid (PAA) binder to S-CPAN electrodes using alkyl carbonate based electrolyte solutions with fluoroethylene carbonate (FEC) as an additive. PAA based binders were found to be superior over PVdF in a previous work, in terms of excellent adhesion and cohesion properties of composite electrodes. FEC is considered a ‘magic’ additive/co-solvent in Li salt electrolyte solutions, working with Li metal or Li-Si anodes and high voltage Li insertion cathodes or S-C composite cathodes as its surface reactions lead to polymerization and formation of effectively passivating surface films. We found that Li-S cells comprising S-CPAN cathodes with PAA binder resolve the inherent problems of cathode structure fragmentation through hydrogen bonding of S-CPAN-PAA and S-CPAN-PAA-Al2O3, which strengthen the cathode structure.3 A major advantage of using FEC-containing solutions is the stabilization of the lithium metal anodes by formation of passivating surface films.4 The combination of these three components — S-CPAN, PAA, and FEC — resulted in outstanding electrochemical performance of practically loaded sulfur cathodes with stable cycle life. We demonstrated pouch cells,5 which contained 100 mAh S-CPAN cathodes with a specific capacity around 3 mAh cm-2, which exhibited very stable.

References

J. Wang, J. Yang, J. Xie, and N. Xu, Adv. Mater.,
2002, 14, 963

B. Scrosati, J. Hassoun, Y.-K. Sun, Energy Environ. Sci. 2011, 4, 3287

J.-Y. Hwang, H. M. Kim, S. K. Lee, J. H. Lee, A. Abouimrane, M. A. Khaleel, I. Belharouak, A. Manthiram, Y.-K. Sun, Adv. Energy Mater. 2016, 6, 1501480

E. Markevich, G. Salitra, A. Rosenman, Y. Talyosef, F. Chesneau and D. Aurbach, Electrochem. Commun., 2015, 60, 42

H.-S. Kang, E. Park, J.-Y. Hwang, H. Kim, D. Aurbach, A. Rosenman, Y.-K. Sun, Adv. Mater. Technol. 2016, 1600052
Chromium Doped Li2RuO3 As a Positive Electrode with Superior Electrochemical Performance for Lithium Ion Batteries
Authors: Yang Yin
Published: February 2020

The miniaturization of portable electronic devices and urgent demand for long-range electric vehicles (EVs) drive researchers to seek for advanced lithium ion batteries (LIBs) as power sources with high energy densities. Traditional cathode materials (LiCoO2, LiMn2O4, LiFePO4 and their derivatives) with specific capacities less than 200 mA h g-1 are not able to fulfil the challenge. As one of the most promising alternatives, lithium-rich layered oxides (LRLOs) with exceptionally high capacities exceeding 250 mA h g-1 have been attracting extensive research interests for high energy density LIBs during the last decade.1-3 However, intrinsic disadvantages of voltage decay and capacity fade resulting from structural instability hinder practical use of LRLOs. Strategies such as ionic doping and surface engineering have been developed to improve electrochemical performance of LRLOs, but with limited understanding of the origins of their high capacity, voltage decay and capacity fade.

Ru-based LRLOs stand out their counterparts for the good rate performance benefiting from low resistivity of Ru-based compounds. As the major component of Ru-based LRLOs, although Li2RuO3 exhibits large specific capacity and good rate capability, it suffers severely from capacity fade and voltage decay upon prolonged cycling. Herein in this work, for the first time, Cr has been employed as a dopant in Li2RuO3 compound and the correlation between Cr doping and electrochemical performance of Li2RuO3 is investigated. Elemental Cr is selected as dopant for plenty of reasons. Firstly, LiCrO2 possesses a layered structure with R-3m symmetry, which has similar oxygen stacking framework with Li2RuO3 layered structure. Besides, the ionic radius of Cr3+ (0.615 Å) is close to that of Ru4+ (0.62 Å). The similarity in crystal structure and ionic radius guarantees that the structure of Li2RuO3 is not destroyed by Cr doping. Secondly, Cr3+/Cr6+ three-electron redox reaction is electrochemically active which is expected to favor the capacity improvement of Li2RuO3 compound, as lots of literatures reported that Cr-doped Mn-based LRLOs showed enhanced reversible capacity because of the introduction of three-electron redox reaction of Cr3+/Cr6+. Thirdly, Singh and colleagues reported that Cr in the Cr-doped composite Li2MnO3-LiMn0.5Ni0.5O2 acts as a catalyst for the activation of Li2MnO3 component in the electrochemical reaction,4 which makes it reasonable to deduce that Cr activates anionic electrochemistry and thus contributes to capacity improvement. Based on the above considerations, we synthesized Cr-doped Li2RuO3 with different doping degrees (Li2RuO3, Li2Ru0.98Cr0.02O3, Li2Ru0.95Cr0.05O3 and Li2Ru0.9Cr0.1O3, denoted as LRO, LRO-Cr0.02, LRO-Cr0.05 and LRO-Cr0.1, respectively) by high-temperature sintering method. It is shown that with appropriate amount of Cr doping, the capacity, rate performance and cycling stability can be significantly improved for Li2RuO3 compound.

Figure 1
Electrochemical Alloying and Supercritical Fluid-Based Synthesis of Antimony Conversion Electrodes with Controlled Anisotropy
Authors: Williamson Grant Andrew , Pandres Elena P. , Holmberg Vincent C.
Published: February 2020

Antimony is one of the most promising high-rate-capability Na- and Li-ion conversion electrode materials, demonstrating extraordinarily high rates of lithiation and sodiation. For example, small isotropic antimony nanocrystals have exhibited stable, reversible, long-term cycling at charge/discharge rates as fast as 20C without significant capacity loss. Herein, we investigate the effect of structural anisotropy on the sodiation of high-capacity, high-power density antimony electrodes fabricated from an engineered set of highly anisotropic, nanostructured antimony electrode materials produced via a supercritical fluid-based synthesis. By controlling reaction conditions, precursor concentration, and ligand choice, the synthesis can be tailored to produce an array of nanostructured antimony electrode materials with a variety of morphologies including platelets, truncated octahedra, and dendritic microstructures. In addition to analyzing the growth processes that promote the supercritical fluid-based synthesis of these anisotropic antimony nanostructures, we discuss how this morphological selectivity can be used to evaluate the effects of structural anisotropy on sodiation and desodiation, and how oxidation and temperature influence the electrochemical alloying process. We hope that a better understanding of the transformations that take place during the high-rate electrochemical alloying of nanostructured antimony will enable the structural optimization of high-rate-capability antimony-based conversion electrodes.
Surface Modification of Mg-Doped P2-Type Na2/3Mn0.65Ni0.2 Co0.15O2 Cathode Materials for Sodium-Ion Batteries
Authors: Wen Yanfen , Sun Shi-Gang
Published: February 2020

Ambient sodium-ion batteries (SIBs) have attracted great attention for large-scale energy storage system due to the concern of the availability and increasing price of lithium resources.[1] Among all the reported Na cathode materials up to date, manganese-based sodium layered transition metal (TM) oxides, such as P2-type Na2/3TMxMn1-xO2 (TM = Ti, V, Cr, Fe, Co, Ni, and mixture of 2 or 3 elements), deliver high reversible capacities and relatively high volumetric density from their compact structural framework.[2] However, the cycle life of the currently developed P2-Na2/3TMxMn1-xO2 is far from the demand of practical application. Current research has shown that Mg doping in layered P2-Na0.67MnO2 is promising in stabilizing the structure and enhancing the electrochemical properties in terms of cycle life and rate performance, yet further enhancement is still necessary.[3] In addition, surface modification has been demonstrated to be effective in protecting the integrity of electrode materials during cycling in lithium layered cathode materials and prolonging the cycling stability; however, its influence is not intensively studied in sodium counterparts.[4] Herein, we synthesized TiO2 coated and Mg doped P2-type Na2/3Mn0.65Ni0.2Co0.15O2 electrode materials and investigated their electrochemical performance and sodium storage mechanism. The preliminary results suggest the cycling stability has been improved by Mg doping. We expect that the sustainable cycling behaviors would be further improved due to the synergistic effects from the composition manipulation of Mg-doping and surface modification of P2-type Na2/3Mn0.65Ni0.2Co0.15O2 in SIBs.

Acknowledgement: The study was supported by NSFC (21621091).

References:

[1] a）H. Yu, Y. Ren, D. Xiao, S. Guo, Y. Zhu, Y. Qian, L. Gu, H. Zhou, Angew. Chem. Int. Ed., 2014, 53, 8963 ; b）N. Yabuuchi, M. Kajiyama, J. Iwatate, H. Nishikawa, S. Hitomi, R. Okuyama, R. Usui, Y. Yamada, S. Komaba, Nat. Mater., 2012, 11, 512; c）H. Pan, Y.-S. Hu, L. Chen, Energy Environ. Sci., 2013, 6, 2338.

[2] R. J. Clément, P. G. Bruce, C. P. Grey, J.Electrochem. Soc., 2015, 162, A2589.

[3] a）J. Billaud, G. Singh, A. R. Armstrong, E. Gonzalo, V. Roddatis, M. Armand, T. Rojo, P. G. Bruce, Energy Environ. Sci., 2014, 7, 1387; b）R. J. Clement, J. Billaud, A. Robert Armstrong, G. Singh, T. Rojo, P. G. Bruce, C. P. Grey, Energy Environ. Sci., 2016, 9, 3240.

[4] a）Y. Chen, Y. Zhang, B. Chen, Z. Wang, C. Lu, J. Power Sources, 2014, 256, 20; b）D. J. Comstock, J. W. Elam, J. Phys. Chem. C, 2012, 117, 1677; c）B. Song, M. O. Lai, Z. Liu, H. Liu, L. Lu, J. Mater. Chem.A, 2013, 1, 9954; d）S. Kalluri, M. Yoon, M. Jo, H. K. Liu, S. X. Dou, J. Cho, Z. Guo, Adv. Mater., 2017, n/a; e）Y. Liu, X. Fang, A. Zhang, C. Shen, Q. Liu, H. A. Enaya, C. Zhou, Nano Energy, 2016, 27, 27; f）K. Kaliyappan, J. Liu, B. Xiao, A. Lushington, R. Li, T.-K. Sham, X. Sun, Adv. Funct. Mater., 2017, n/a.
Manipulating Protein Configuration for High-Performance Solid Polymer Electrolytes
Authors: Fu Xuewei , Li Chunhui , Jewel Yead , Wang Yu , Liu Jin , Zhong Weihong
Published: February 2020

Solid polymer electrolytes (SPEs) are well known for their excellent mechanical properties and high safety. It will be significant to develop advanced SPEs for substituting currently used organic liquid electrolytes. However, determined by their ion-transport coupled with mobility of polymer segments, SPEs usually exhibit low ionic conductivity (10-8 ~ 10-6 S/cm) at room temperature, which severely limits their practical applications. Thus far, efforts on enhancing the ionic conductivity of SPEs have been primarily focusing on reducing crystallinity degree of the polymer hosts via introducing plasticizers, advanced nanofillers, other polymers, etc. while there have not existed effective ways to the control of the ion-transport pathways inside the SPEs.

In our work, we discovered that by manipulating the configuration of denatured soy protein, the transportation of Li+ can be significantly promoted, which is of great interest for fabricating high-performance SPEs. Via carefully controlling critical factors, including denaturation of soy protein, loading level of lithium salt and temperature for the evaporation process of the electrolyte preparation, a protein-based solid electrolyte with high ionic conductivity (ca. 10-5 S/cm at room temperature) and modulus (ca. 1 GPa) was achieved, which has never been realized in any conventional SPEs. Meanwhile, the soy-protein-based SPE presents high lithium ion transference number of ca. 0.94. Molecular dynamic simulation results indicate that evaporation temperature for electrolyte preparation plays a critical role in controlling the configuration of protein. As a result, a more flexible protein configuration allows strong interactions between anions of lithium salts with the backbone oxygen and negative charge side groups of protein to form anion clusters that can facilitate the transportation of Li+. It is therefore speculated that this unique ion-transport mechanism is ceramic-like and is decoupled with mobility of protein chains.

In addition, by introducing ceramic nanoparticles into denaturation of soy protein, the configuration of the protein was dramatically changed to result in a type of highly efficient nanofiller that enables fast ion-transport. A composite polymer electrolyte based on poly(ethylene oxide) (PEO) loaded with such hybrid nanofillers shows one order of magnitude improvement in ionic conductivity at room temperature, as compared with the one with untreated nanofillers. Moreover, the composite polymer electrolyte was demonstrated improved mechanical properties, and importantly improved adhesion properties that greatly benefit interfacial properties with the electrodes. The studies may open a new avenue for developing high-performance SPEs with promoted ion-transport by manipulating the configuration of the protein.
In Situ Mass Spectrometry Studies of Gas Evolution Reactions During Cell Cycling in Aqueous Lithium Ion Batteries
Authors: Uddin Jasim , Addison Dan , Wang Chunsheng , Xu Kang
Published: February 2020

In terms of safety, toxicity, cost and manufacturing simplicity, lithium ion batteries with aqueous electrolytes offer significant advantages over their non-aqueous counterparts. Despite these advantages, a low thermodynamic stability window of water (1.23 V, 2.62 V to 3.85 V vs. Li+/Li at pH 7) yields a low cell voltage, hence a low energy density system as compared to state-of-the-art non-aqueous Li-ion batteries. However, recent ‘water in salt’ (WiS),1 ‘water in bisalt’ (WiBS)2 and ‘hydrate melt’3 electrolytes widen the electrochemical stability window of water from 1.23V to >3.0V (~1.8 V to 5.0 V vs. Li+/Li), which results an energy density >100 Wh/kg when coupled a S-anode to a LiMn2O4 cathode.4 While these reports highlight impressive overall cell performances,1-4 gas evolution analyses of H2 at anode via HER and O2 at cathode via OER, or any other gas producing parasitic reaction, e.g. Li2S + 2H2O → H2S + 2LiOH @ S-anode, are not adequately addressed. At Liox, we anticipate that H2 and O2 generation from water electrolysis, or any other gas generating parasitic reaction would be detrimental to overall cell performance, and severely limit their ability to be practical and safe energy storage systems. To validate this conjecture, we have designed a special hermetically sealed Swagelok cell with known volume, comprising a high precision pressure sensor (Omega) and a three way Valco valve which can easily be connected to a high resolution mass spectrometer for qualitative and quantitative - in situ or ex situ - analysis of evolved gases during cell operation. We have tested a number of cathode and anode active materials – such as LFP, LMO, NMC, NCA, LCO, S, LTO, C-TiO2, etc. in the hermetically sealed cell. To study the cathode and anode separately, we assembled a series of symmetric cells; either cathode/cathode for OER or anode/anode for HER, and cycled them to monitor pressure changes, and identify and quantify the evolved gases by high precision RGA mass spectrometer. In this presentation, a series of symmetric and full-cell cycling data (>300 cycles) to discern gas evolving parasitic side reactions, pressure changes during cell operation, in situ and ex situ mass spectrometric analysis of evolved gases will be discussed.

References:

Suo, O. Borodin, T. Gao, M. Olguin, J. Ho, X. Fan, C. Luo, C. Wang, K. Xu, Science
350, 938 (2015).

Suo, O. Borodin, W. Sun, X. Fan, C. Yang, F. Wang, T. Gao, Z. Ma, M. Schroeder, A.V. Cresce, S. M. Russell, M. Armand, A. Angell, K. Xu; C. Wang, Angew. Chem. Int. Ed.
55, 7136 (2016).

Yamada, K. Usui, K. Sodeyama, S. Ko, Y. Tateyama, Nature Energy
1, 16129 (2016)

Yang, L. Suo, O. Borodin, F. Wang, W. Sun, T. Gao, X. Fan, S. Hou, Z. Ma, K. Amine., K. Xu, C. Wang, Proc. Natl. Acad. Sci. USA
114, 6197 (2017).
Enabling High Initial Coulombic Efficiency of Hard Carbon By a Pre-Lithiation Treatment for Sodium-Ion Batteries
Authors: Xiao Biwei , Engelhard Mark H , Reed David , Sprenkle Vincent , Li Xiaolin
Published: February 2020

Hard carbon (HC) has been found to be an important anode material for sodium-ion batteries (SIBs) since graphite does not allow for the intercalation of sodium ions with a large size. While competitive capacity has been achieved using HC, the performance is still plagued by the low initial Coulombic efficiency (ICE), which stems from the electrolyte decomposition that forms a thick solid electrolyte interphase (SEI) and irreversibly trapped Na ions within the nano-pores. This defect becomes particularly profound when tested in full cell since the amount of Na is very limited.

In this study, we have systematically compared the performance of HC in carbonate and ether electrolytes and found that ether electrolyte demonstrates competitive performance with conventional carbonate at room temperature and significantly improved performance at -20 oC. The advantage of limited SEI from ether electrolyte also enabled a pre-lithiation treatment on the HC electrode using stabilized lithium metal powder (SLMP) to boost the initial Coulombic efficiency (ICE) to above 90% while maintaining the high capacity and good cycling stability. When coupled with Na3V2(PO4)3, the full cell with pre-lithiated HC demonstrates significantly improved ICE, cycling stability and capacity compared to pristine HC. Systematic characterizations and theoretical modelling have been performed to understand the effect of SLMP on the SEIs formed in different electrolytes. This work has provided a novel method to obtain high-performance SIBs with HC as the anode material.
Using in-Situ Neutron Reflectivity to Probe Solid Electrolyte Interface Formation As a Function of Polymer Binder on Si-Anodes
Authors: Browning Katie L , Browning James F , Veith Gabriel M.
Published: February 2020

Polymer binders play a critical role in the fabrication of composite electrodes. This is particularly true for silicon electrode materials where due to the large volume expansion during cycling a mechanically robust binder is needed to minimize Si pulverization and prevent electronic isolation. Currently, the most widely used binder is polyacrylic acid (PAA); however, there is very little knowledge of the effect any polymer binder has on the formation and composition of the solid-electrolyte interface (SEI). In this work we report on the formation and growth of the SEI layer as probed with in situ neutron reflectivity. We also explore the effect of adding an electronically conductive binder, poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) on SEI formation on thin film Si anodes. In addition to the in situ reflectivity measurements at open circuit voltage and as a function of the state of charge, x-ray photoelectron spectroscopy (XPS) and infrared spectroscopy studies were used to study the elemental composition of the SEI layer formed. Electrochemical impedance spectroscopy (EIS) was also performed to better understand how the Li-ion is transported through the polymer layer into the Si.

Acknowledgement: This research was supported by the Vehicle Technologies Office, Hybrid Electric Systems Program, David Howell (Manager), Battery R&D, Brian Cunningham and Peter Faguy (Technology Managers), at the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy. Neutron reflectometry measurements were carried out on the Liquids Reflectometer at the Spallation Neutron Source which is sponsored by the Scientific User Facilities Division, Office of Basic Energy Sciences, U.S. Department of Energy.
Synthesis and Electrochemical Properties of ZnO Nanotube Materials
Authors: Kim Han-Seul , Kim Jae-Hun
Published: February 2020

Zinc oxide (ZnO) is one of the widely used metal oxide materials in industry. It is cheap and chemically stable. In addition, it has a wide bandgap (3.37 eV) and a high binding energy in a crystalline state (60 meV), which ensure efficient exciton emission. Based on these characteristics, ZnO has been applied from traditional industry such as white pigment and sunscreen to high technology industry that includes semiconductors, optical materials, conductive films, solar cells, biosensors, and light emitting diodes.

Nanostructured ZnO materials can be synthesized by various methods such as hydrothermal, vapor deposition, and vapor-liquid-solid processes. The shapes of the nanostructure are rod, wire, tube, ring, spring, sheet, propeller, etc. These various nanostructures can be beneficial for enabling fast electronic and ionic transport in electrochemical energy storage device applications such as rechargeable batteries and supercapacitors. However, the low electronic conductivity of ZnO is still a problem when it is used as electrode materials for lithium rechargeable batteries.

In the present work, carbon coated ZnO nanotube materials were formed by a simple one-pot synthesis method. Conventional ZnO nanotube structures have been synthesized by relatively complex methods and have usually grown on the substrates. Here, free-standing ZnO nanorod materials were prepared by a hydrothermal process and then they were transformed into nanotubes with simultaneous carbon-coating during annealing process. The ZnO nanotube structure is suitable for alleviating volume changes for Li insertion and extraction during cycling and carbon coating enables fast electronic transport with a buffering effect for volume changes of the active materials.
Ruthenium Bromide for High Efficiency Li–O2 Batteries
Authors: Lee Seon-Hwa , Sun Yang-Kook
Published: February 2020

A suitable bifunctional soluble catalyst is needed to increase the efficiency of Li-O2 batteries.1-3 We anticipated that the ruthenium ion, dissolved in the electrolyte, will not only overcome the disadvantages of solid phase catalysts, but also reduce the overpotential for both charge and discharge. This is possible due to the suitable redox potential of the ruthenium ion, which effectively reduced the oxygen evolution reaction (OER) overpotential, and the affinity between the ruthenium ion and oxygen, which facilitated the oxygen reduction reaction (ORR) and suppressed the degradation of the cathode. we propose a new soluble catalyst, ruthenium bromide, for Li–O2 batteries. The battery using ruthenium bromide clearly exhibited enhanced cycling performance, increasing round-trip efficiency (from 68.2% to 80.5%) and rate capability. A new understanding and application of the soluble rutheniumcatalyst, which is commonly used as a solid catalyst, will not only overcome the existing problems but also provide a promising platform for Li–O2 batteries.

Reference

Grande, E. Paillard, J. Hassoun, J.-B. Park, Y.-J. Lee, Y.-K. Sun, S. Passerini and B. Scrosati, Adv. Mater., 2015, 27, 784.

H. Lee, J.-B. Park, H.-S. Lim, and Y.-K. Sun, Adv. Energy Mater. 2017, 1602417

-J. Kwak, H.-G. Jung, S.-H. Lee, J.-B. Park, D. Aurbach and Y.-K. Sun, J. Power Sources, 2016, 311, 49.
Thin Conductive Conformal Coating on Prepared Electrode for High Performance Lithium-Ion Battery
Authors: Ahn Jinhyeok , Jang Eun Kwang , Cho Kuk Young
Published: February 2020

Nowadays, lithium ion batteries (LIBs) have been widely used in portable electronic devices. However, there are many needs to improve power and energy density for LIB to meet the demands of applications in electric vehicles and energy storage systems. Surface modification, especially surface coating, is one of the effective methods to improve the electrode performance in LIB. Many studies have been reported on advantages of surface coating on single particle level. Nevertheless, the decrease in the tap density and the complex manufacturing conditions can be problematic for a particle-scale coating. Here, we report a facile synthesis of conformal thin-layered conducting poly(3,4-ethylenedioxythiophene) (PEDOT) via vapor reacting printing (VRP) on prepared electrodes. A positive electrode based on micron-sized LiFePO4 (LFP) was used to highlight the improvements in the electrical and ionic conductivity by conductive coating.
A Polyimide Based on 3,4,9,10-Perlenetetracrboxylic Dianhydride(PTCDA) As High Performance Cathode for Sodium Ion Batteries
Authors: Gu Tiantian , Zhou Min , Wang Kangli , Jiang Kai
Published: February 2020

Sodium ion batteries have attracted aroused attention as a novel kind of energy storage technology, due to its abundant resources, low cost and environmental friendliness. Similar to LIBs, an overwhelming majority of host materials developed so far for SIBs are based on transition-metal compounds, which have serious cost and negative environmental impacts on battery applications. In contrast, redox-active organic materials have competitive advantages of low cost，resource sustainability and structural diversity, being an ideal candidate for promising candidates for large-scale energy storage applications1. In this study, A Polyimide composite synthesized from 3,4,9,10-perlenetetracrboxylic dianhydride (PTCDA) and phenylene diamine (PDA) was investigated as a cathode materials for non-aqueous Na-ion batteries2. The polymer was synthesized via a facile dehydration condensation reaction in quinoline as shown in Figure 1a. And this composite demonstrates a high reversible capacity of 99.6 mAh g-1 at potential of 2.2 V (vs Na+/Na), showing a great potential as cathode materials for sodium ion batteries (Figure 1b and 1c ).

1.Zhang, Y.,Wang, J.,Riduan, S. N. J. Mater. Chem. A, 39 14902 (2016)

2.Song, Z.,Zhan, H.,Zhou, Y. Angewandte Chemie, 49 (45): 8444-8.(2010)

Figure 1
P2-Type Layered Cathode Materials for Sodium-Ion Rechargeable Batteries with High Initial Coulombic Efficiency
Authors: Eom Ji-Yong , Kim Seong In , Yoo Seung-Eul
Published: February 2020

Sodium-ion rechargeable batteries (SIBs) have attracted great attention as promising next-generation rechargeable batteries, especially for large-scale energy storage systems (ESS), owing to the natural abundance of Na resources and the similarities in their chemical structure and reaction mechanism to commercial lithium-ion batteries (LIBs). Thus, enormous efforts have been made to improve the electrochemical performance of SIBs through the development of novel cathode materials.

According to the previous literatures, P2-type layered cathode materials for SIBs have suffered from their low initial coulombic efficiency, which inevitably requires the pre-sodiation of carbon anode materials under full cell systems. In this regard, we focused on how to increase their initial charge capacity with sacrificial salts in the level of electrode fabrication. Actually, the suppression of irreversible capacity of P2-type layered cathode materials are challenging without specific electrode design.

Thus, in the present study, we suggest new electrode fabrication process with sacrificial salts (i.e. NaN3) to reduce the high initial irreversible capacity of P2-type layered cathode materials for SIBs.
Effects of Surface Treatments of Lithium Metal for All Solid Lithium Batteries
Authors: Park Sang Jun , Kim Min-Young , Kim Da-Hye , Jung Ha-Young , Ryu Hye-Min , Ban Hee-Jung , Kim Yoong-Ahm , Kim Ho-Sung
Published: February 2020

Recently, all solid lithium batteries have been studied for a solution of safety problem in EV and ESS applications. The batteries are composed of cathode, solid electrolyte and lithium metal as anode. In here, lithium dendrite and dead lithium were formed on the surface of lithium electrode during charge and discharge cycling, resulting in the rapid degradation of battery capacity.

In order to improve the above problems in all solid lithium batteries, interface layer, which is made of graphite-based thin composite film, was introduced between solid electrolyte and lithium metal. The interface layer showed a great improvement of cycling performance of all solid lithium battery. Furthermore, it was possible to reduce the thickness of lithium metal due to the reduction of lithium consumption during the charge and discharge cycling.
Investigating the Reaction Mechanism of Sodium Insertion/Extraction in SnF2 Anode Material
Authors: Ali Ghulam , Chung Kyung Yoon
Published: February 2020

Sodium-ion batteries (SIBs) are considered as a potential candidate for electrical energy storage system (ESS) because of their advantages such as low-cost system and evenly distributed sodium resources worldwide. However, there is need to explore new electrode materials for the realization of SIBs. Particularly, the anode side of SIBs needs more improvements as commonly investigated anodes in lithium-ion batteries (LIBs) such as graphite and silicon do not intercalate sodium ions.

In the search for high capacity anodes for SIBs, we have investigated electrochemical properties of a nanocomposite based on SnF2 and acetylene black. The nanocomposite electrode delivers a reversible capacity of 563 mAh g-1 which is higher than the specific capacity of 323 mAh g-1 of the micron-sized bare SnF2 electrode. The sodium insertion/extraction process of the high-performing nanocomposite is revealed by in-situ XRD, ex-situ XAS and TEM techniques. The reaction mechanism revealed using in-situ XRD show the existence of a solid solution of two or more compositions during cycling. Ex-situ XAS reveals the electronic and atomic configurations of SnF2 at different potential states during dis/charging. The XAS results reveal that the valence change of Sn follows the conversion (SnF2 + 2Na → Sn + 2NaF) and the alloying (Sn + XNa → SnNaX) reaction upon sodium insertion into a composite.
Fuel Cell Performance and Durability of Intermetallic Oxygen Reduction Catalysts
Authors: Pan Yung-Tin , Kim Yu Seung , Li Junrui , Sun Shouheng , Spendelow Jacob S
Published: February 2020

Platinum-based alloy catalysts for the oxygen reduction reaction (ORR) continue to be the industry standard for fuel cell applications, but improvements are needed to increase ORR activity and durability. Despite extensive study, the effects of structure and composition on real world performance and durability in fuel cells are poorly understood. Most research to date has examined random alloy structures, but preliminary results from intermetallic catalysts, especially intermetallic tetragonal structured catalysts, have indicated that superior performance and durability can be achieved through creation of ordered intermetallic structures. Results so far indicate that the degree of ordering is a critical parameter in determining intermetallic catalyst activity and durability, with fully-ordered face-centered tetragonal (fct) FePt catalysts exhibiting substantially improved activity and durability compared to partially ordered phases [1].

Most work on intermetallic nanocatalysts reported so far has been based on ex situ testing methods that use an idealized aqueous electrochemistry environment. While these ex situ methods are inexpensive and convenient, they do not reliably predict performance and durability in real fuel cells. Therefore, rigorous catalyst testing in fuel cells is needed to build understanding of the relationship between catalyst properties and fuel cell performance and durability.

In our earlier work, we observed the instability of the intermetallic surface accompanied by substantial iron and performance loss after subjecting to the DOE catalyst AST (30,000 trapezoidal cycles between 0.6 and 0.95 V with 0.5 s rise time) in operating fuel cells. However, when the surface was chemically modified towards a Pt rich surface on the fct core, the stability was significantly improved (Figure 1). Initial results depicted indicate that Pt-on-fct-FePt can have performance comparable or even better than a baseline commercial Pt/C, despite the use of larger particles (5-7 nm for fct-FePt/C vs. 2-3 nm for Pt/C). Notably, the Pt-on-fct-FePt exhibits lower loss of performance following the 30,000 cycle AST. Ongoing work seeks to focus on optimizing the surface structure of fct-FePt and fct-CoPt intermetallic nanoparticle catalysts such that a synergistic effect between the surface and core can be established, i.e., a stable Pt surface that protects the fct-core that is thin enough to benefit from the geometric and electronic effects from the core.

Fig. 1. Fuel cell polarization behavior of Pt/C and fct-FePt/C before and after the 30,000 cycle AST. H2/air, 80°C, 100% RH, 150 kPaabs, 0.1 mgPt/cm2.

References

Q. Li et al., "New Approach to Fully Ordered fct-FePt Nanoparticles for Much Enhanced Electrocatalysis in Acid," Nano Lett. 2015, 15, 2468−2473.

Acknowledgements

This research is sponsored by the Fuel Cell Technologies Office, Office of Energy Efficiency and Renewable Energy, U.S. Department of Energy.

Figure 1
Development of Best Practices and Standard Protocols in Benchmarking Photoelectrochemical (PEC) Hydrogen Production
Authors: Xiang Chengxiang("CX")
Published: February 2020

Photoelectrochemical (PEC) Hydrogen Production has advanced significantly in recent years, in particular, PEC devices with solar-to-hydrogen (STH) conversion efficiency that exceeded 10% were demonstrated in a range of configurations at the laboratory scale. To further advance this technology and reach the bench scale (0.1 kg/day) and sub-scale (2 kg/day) operational platforms, development of comprehensive Best Practices in screening, characterization and benchmarking at materials level, component level, device level and system level is critical.

In this presentation, I will talk about recent community-based efforts in defining targets, best practices and gaps in PEC hydrogen production in HydroGEN Energy Material Network (EMN) consortium. Specific challenges related to PEC will be discussed including scale up challenges, integration challenges at component level, lack of performance data and test protocols for photoelectrodes under real-world operating conditions and lack of fundamental understanding of photoelectrode corrosion mechanisms and accelerated test protocols. In addition, a briefly summary and status reports on lab EMN nodes/capabilities for PEC water-splitting will be addressed. Cross-cutting interactions with other advanced water-splitting technologies, including low/high temperature electrolysis and solar thermochemical water splitting, will also be discussed.
PbI2 Thin-Films for Photoelectrochemical Hydrogen Evolution
Authors: Fermin David , Tiwari Devendra
Published: February 2020

PbI2 has become a highly prominent material in the field of photovoltaics as the key precursor in the fabrication of organo-halide perovskites films [1]. Despite intensive research in this area, the role of unconverted PbI2 in perovskite cells remains controversial. In fact, very little is known about the behaviour of PbI2 as a photocathode. In this contribution, we examine the photoelectrochemical properties of high quality PbI2 thin films obtained by gas phase anion replacement [2].

The preparation of PbI2 films is initiated by growing a thin PbS film on F:SnO2 electrodes, followed by spontaneous gas phase iodination at 200 ˚C. The structure and optical properties of the thin films were investigated by XRD, SEM, Raman Spectroscopy, diffuse reflectance and room temperature photoluminescence. The structural and spectroscopic information, supported by DFT calculations (PBESOL functionals), demonstrated the formation of the 2H- phase of PbI2 with a high degree of purity and a band gap of 2.4 eV. Electrochemical impedance spectroscopy in KI containing solutions showed a clear p-type behaviour with a flat band potential located 0.175 V vs Ag/AgCl and an effective majority carrier density of 1.6×1015 cm-3.

Photoelectrochemical studies in Ar-saturated KI solutions were characterized by a nearly ideal semiconductor-electrolyte junction at low illumination levels. Incident-photon-to-current efficiency exhibits values close to 50%, which can be quantitatively rationalized in terms of reflection losses, the width of the space charge region and a minority carrier diffusion length of 80 nm. The remarkable feature of this photocathode is the absence of surface recombination even at potentials close to the flat band value. The efficient hydrogen photogeneration is achieved at neutral pH and in the absence of co-catalysts. We shall briefly discuss the origin of the nearly ideal semiconductor-electrolyte junction behaviour and potential routes for stabilising the PbI2 surface for solar fuel applications.

References

Yang and J. You, Nature 544 (2017) 155

Tiwari and D.J. Fermin, Electrochim. Acta 254 (2017) 223
Colloidal Ternary Ni1-xCoxSe Alloy Nanocrystals with tunable compositions: Synthesis, Characterization and Electrocatalytic properties for the Oxygen Evolution Reaction
Authors: Manna Liberato , Wang Mengjiao , Shinde Dipak , De Trizio Luca
Published: February 2020

Oxygen evolution reaction(OER) is one of the two half-reactions in water splitting. Sustainable OER is an essential prerequisite in hydrogen production from water. In the past few years, many research efforts have been directed towards the development of electrocatalysts for OER, which are based on noble metals and transition metal oxides. But these materials suffer from poor conductivity. Recently, it has been found that, transition metal chalcogenide materials, especially Ni- and Co- based compounds, can catalyze OER efficiently. However, the research on these systems is at the very beginning, and few syntheses of Ni1-xCoxSe nanocrystals (NCs) have been reported in the literature till now. Herein, we report a simple colloidal synthesis approach to grow ternary Ni1-xCoxSe NCs with tunable composition and study their OER properties. The phase of the nanocrystals is hexagonal irrespective of their composition. The composition of Ni and Co in the NCs can be easily controlled by tuning the experimental parameters. By performing OER on samples with different Ni/Co ratio, we optimized the composition for obtaining high performance OER. The best performing samples exhibit a catalytic OER current of 10 mA/cm2 at a small overpotential of 1.5 V vs. RHE with extended long-term stability. The detailed results will be presented in the meeting.

Figure. (a) TEM image of Ni0.37Co0.74Se and (b) Polarization curves of OER for NCs with different Ni/Co ratios

Figure 1
Nitrogen Doping on Carbon Paper Electrodes
Authors: Singh Ashutosh Kumar , Yasri Nael , Karan Kunal , Roberts Edward P.L.
Published: February 2020

Carbon papers are widely used as electrode materials for electrochemical applications, include but not limited to; flow batteries, fuel cells, supercapacitors, sensors, and bioelectrochemical systems. In order to increase the hydrophilicity of carbon paper, and hence improve the electrochemical properties, one of the common approaches is to incorporate oxygen containing functional groups when heating in air at relatively elevated temperature, resulting in increases of the wetting properties of carbon paper and improve the electrochemical performance. As our work demonstrate here, this approach is not ideal, especially when dealing with electrochemical system that contain high acid concentration or are sensitive to hydrogen peroxide production from oxygen reduction. We provided here a simple alternative approach via a pre-physiochemical treatment to successfully prepare a nitrogen-doped carbon paper that reduces the in-situ H2O2 production and at the same time, remarkably increases the electrochemical activity of the electrode. Characterisation using Raman spectroscopy for the prepared N-doped graphite paper indicates higher defects in structure that fit well with XPS and BET analyses and provide explanation of many interfacial charge transfer observations. For example, VO2
+/VO2+ and [Fe(CN)6]4−/3− redox couples show with the N-doped carbon paper a superior catalytic activity compared to other preheated or bare carbon papers could be obtained. Thus, the prepared N-doped carbon paper, can provide alternative promising electrode material which is suitable for higher efficiency for various electrochemical applications.
Multi-Modal Catalytic Cascades on Carbonaceous Scaffolds
Authors: Chavez Madelaine Seow , Monclova Jose , Hickey David P , Abdellaoui Sofiene , Gonzales Ivana , Minteer Shelley , Atanassov Plamen
Published: February 2020

Fundamental understanding of the ways organic and/or inorganic catalysts can be incorporated with enzymes to enhance the efficiency of multi-step reactions can lead to knowledge that is crucial for any further improvements in the development of multi-component multi-step catalytic cascades. This knowledge can provide essential clues to the novel design of systems for energy conversion and harvesting as well as for production of advanced materials that require multi-step catalysis. The goal of this project is to develop strategies for spatially organizing three different catalysts (biological, molecular, and inorganic) using 3D-Graphene nanosheets (3D-GNS) as a scaffold and apply it to efficiently catalyze model catalytic cascade: multi-step oxidation of glycerol [1,2].

In this work, we first studied the immobilization of oxalate decarboxylase (OxDC) from Bacillus subtilis, through physical absorption and tethering using 1-pyrenebutyric acid N-hydroxysuccinimide ester (PBSE) on conductive carbonaceous supports such as multi-walled carbon nanotube buckypaper and 3D-GNS. An indirect enzymatic assay using NAD-dependent formate dehydrogenase was performed to determine the kinetic parameters (K
M
V
M) of immobilized OxDC onto these supports. We also employed cyclic voltammetry to study the immobilization of a molecular catalyst, pyrene-tethered TEMPO derivative (TEMPO = 2,2,6,6-tetramethylpiperidine-N-oxyl) on 3D-GNS. Furthermore, we explored optimal strategies to incorporate both OxDC and molecular catalysts in a way that will enable an efficient two-step catalytic cascade - the last two steps in the glycerol oxidation mechanism (Figure). Results of electrochemical studies show that OxDC and pyrene-TEMPO were successfully immobilized on the carbonaceous scaffold. Moreover, it was shown that this hybrid catalyst can catalyze two different reactions sequentially (i.e. conversion of oxalate to formate by OxDC/3D-GNS and oxidation of formate to CO2 by pyrene-TEMPO/3D-GNS).

[1] S. Abdellaoui, D. P. Hickey, A. R. Stephens, and S. D. Minteer, Recombinant oxalate decarboxylase: enhancement of a hybrid catalytic cascade for the complete electro-oxidation of glycerol. Chem. Commun., 51, 14330-14333 (2015).

[2] S. Abdellaoui, M. S. Chavez, I. Matanovic, A. R. Stephens, P. Atanassov, S. D. Minteer, Hybrid molecular/enzymatic catalytic cascade for complete electro-oxidation of glycerol using a promiscuous NAD-dependent formate dehydrogenase from Candida boidinii. Chem. Commun., 53, 5368-5371 (2016).

Figure 1
Analyzing the Legal and Economic Cost Barriers to the Recycling of Advanced Battery Chemistries
Authors: Howes John Howes, Redland Energy
Published: February 2020

A new generation of rechargeable batteries is entering the market to provide power for energy-intensive automotive, communications, utility, manual labor and manufacturing applications. These new batteries also are creating environmental and safety challenges because they are designed, used and discarded in a linear process with limited material recovery, rather than recycled in a safe closed-loop, circular manner. This stands in contrast to lead-acid batteries, which are 99 per cent recycled because the materials can be economically recycled for use in new batteries. U.S. regulations governing lead-acid batteries, however, are not applied comparably to other battery chemistries made with lithium, nickel and various rare earth, causing waste disposal issues. In addition, U.S. regulations are not reflected in other countries. This results in a “race to the bottom” in which many spent batteries (including lead-acid) are exported to poorly regulated recyclers outside the U.S. To evaluate potential closed-loop solutions to issues posed by inconsistent regulation, the current state of law governing hazardous waste disposal (including the “Universal Waste“ rule) is critically examined in this paper. An analytical tool is proposed that would enable equitable comparisons among the full range of battery chemistries (lead-acid, lithium, etc.) on a levelized basis by taking into account internal manufacture costs that are recovered in a retail battery price and external disposal costs that are not. This levelized cost model will help in the analysis of various approaches to circular materials management.
Wholistic Electrochemical Biosensor for the Combinatorial Detection of Alcohol and Glucose in Perspired Sweat
Authors: Bhide Ashlesha , Muthukumar Sriram , Prasad Shalini
Published: February 2020

In this paper, we demonstrate a novel, flexible electrochemical biosensor of the simultaneous detection of glucose and alcohol in perspired human sweat for wearable sensing applications. Evaluation of bodily fluids such as blood, sweat, urine has allowed patients and health-care professionals to track their vital parameters reliably through non-invasive monitoring. Human sweat is one such fluid that contains valuable medical information which can be used to develop real-time, healthcare management devices. Literature studies have shown that sweat alcohol content (SAC) is well correlated to blood alcohol content (BAC). Alcohol consumption modifies blood glucose levels of a diabetic individual depending on their nutrition state inducing either hypoglyceamia or hyperglyceamia. The motivation of this study was to build a sweat based sensor platform for alcohol and glucose management to monitor glucose levels on moderate consumption of alcohol of diabetic social drinkers in low volumes of sweat. The developed sweat biosensor employs a metal- metal oxide electrode stack on a flexible substrate for the non-invasive, low- volume detection of a cohort of glucose and alcohol molecules in sweat through a stable enzyme immunoassay chemistry. Non-faradaic electrochemical impedance spectroscopy (EIS) is the signal transduction mechanism used to detect the presence of glucose and alcohol in sweat. The detection of these molecules is achieved by measuring impedance changes occurring at the electrode- electrolyte interface due to the formation of electrical double layer. Binding events and enzyme catalysis reactions modulate the electrical double layer (EDL) which contribute to the overall impedance change of the system. Detection of sweat glucose levels in the presence of alcohol is demonstrated on the sensor systems at a specific frequency.