bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electrolyte Effects on Single Crystal Cyclic Voltammograms
Authors: Jensen Kim Degn , Bagger Alexander , Petersen Amanda Schramm , Wan Hao , Rossmeisl Jan , Escudero-Escribano María 
Published: December 2020

Insights into the governing mechanisms relevant for electrocatalytic energy conversion is of fundamental interest for future energy schemes aimed at combating fossil dependence and anthropogenic CO2 emissions.1 Electrocatalytic reactions occur at an electrode’s surface-electrolyte interface (see figure 1a). In this interface both geometric and electronic effects determine the selectivity and efficiency of the electrocatalytic reaction.2,3 Simultaneously, the structure and properties of the electrochemical interface are affected not only by the potential applied to the electrocatalyst, but also the pH of the solute4 as well as the cations/anions present in the electrolyte.3,5

Given recent advances on the generalized computational hydrogen electrode (GCHE)6 it is now possible to predict the most probable surface structure using ab initio molecular dynamics (AIMD) and density functional theory (DFT). These structures can be represented as 2D phase diagrams of the interface at any given potential. Herein, we present the basic methodology for creating such diagrams and how to correlate these with experimental cyclic voltammograms (CVs).7 CVs of Pt(111) under different electrolyte conditions (see figure 1b) have been investigated using a rotating disk electrode (RDE) setup and compared with DFT calculations. Our work addresses the impact cations, anions and pH have on the surface of Pt(111) electrodes and what one may extrapolate when contemplating real fuel cell devices.
We herein show that combining experimental model studies with theoretical calculations through the GCHE framework opens up for a new and powerful tool for interpreting CVs of well-ordered metallic M(hkl) interfaces8 for a wide range of electrocatalytic reactions.
References

S. Chu, and A. Majumdar, Nature, 488, 294–303 (2012);

K. D. Jensen, J. Tymoczko, J. Rossmeisl, A. S. Bandarenka, I. Chorkendorff, M. Escudero-Escribano, and I. E. L. Stephens, Angew.
Chemie Int. Ed., 57, 2800–2805 (2018);

D. Strmcnik, M. Escudero-Escribano, K. Kodama, V. R. Stamenkovic, A. Cuesta, and N. M. Marković, Nat. Chem.,
2, 880–885 (2010);

A. Bagger, L. Arnarson, M. H. Hansen, E. Spohr, and J. Rossmeisl, JACS, 141, 1506–1514 (2019);

R. Rizo, E. Herrero, and J. M. Feliu, PCCP, 15, 15416 (2013);

J. Rossmeisl, K. Chan, R. Ahmed, V. Tripkovic, and M. E. Björketun, PCCP,
15, 10321 (2013);

J. Rossmeisl, K. D. Jensen, A. S. Petersen, L. Arnarson, A. Bagger, and M. Escudero-Escribano, Submitted-under review, (2020);

A. Bagger, R. M. Arán‐Ais, J. H. Stenlid, E. Campos dos Santos, L. Arnarson, K. D. Jensen, M. Escudero‐Escribano, B. R. Cuanya, and J. Rossmeisl, ChemPhysChem, 20, 3096-3105 (2019);

Figure 1
Mechanistic Insights on Enhanced Activity of Cu-Deposited Fibrous Electrocatalyst for Oxygen Evolution Reaction
Authors: Morinaga Asuka , Uchiyama Shunsaku , Tsutsumi Hiromori , Katayama Yu 
Published: December 2020

Water electrolysis is an ideal method for producing hydrogen, which is expected as a next-generation energy carrier. However, the sluggish reaction kinetics of the oxygen evolution reaction (OER) limits the overall energy efficiency.1,2 Therefore, designing efficient electrocatalyst for the OER is crucial and has been studied extensively for more than a few decades.3 Precious metal catalysts such as RuO2 and IrO2 exhibit high activity,4,5 but are expensive, and transition metals have been attracted as alternative catalysts.6

In this study, a fibrous Cu catalyst was synthesized as a highly active and low-cost OER catalyst. An electrospinning method was selected to synthesize a fibrous polymer substrate, which was subsequently coated with Cu by electroless deposition. We applied Cu, which is a low cost and has excellent electrical conductivity as an electrocatalyst. As a geometric structure, fiber shape was adopted to increase the specific surface area and improving the diffusion efficiency of the catalyst. We selected PVdF-HFP as catalyst support, to promote the diffusion of the ions in the electrolyte and enhance the activity as a catalyst by its ferroelectricity.
In order to clarify the effect of geometric structure on the OER activity, Cu catalysts were synthesized by various methods, including drop-casting, impregnation, and electrospinning. It was found that the fibrous Cu catalyst exhibited the best OER activity amongst all the geometric structures tested in this study, probably due to the increased active surface area as well as better mass transport and diffusion. Furthermore, the effect of the dielectric properties of PVdF-HFP on the OER activity was clarified. The molecular orientation of PVdF-HFP was evaluated by infrared (IR) spectroscopy, which indicates that the stretching and annealing treatment can effectively increase its electric polarizability. Linear sweep voltammetry (LSV) confirmed that the fibrous Cu catalyst with stretching and annealing treatment showed superior OER activity compared to the pristine fibrous Cu catalyst, indicating the large electric polarizability also enhanced the OER.
Based on these results, it was clarified that the improvement of the OER activity of the fibrous Cu catalyst was due to the following reasons; (i) improvement of mass transport by fibrous structure, and (ii) optimization of the OER reaction energetics by catalyst(Cu)-support(PVdF-HFP) interaction. Optimizing both geometry and electronic structure of the electrocatalyst provides a new design strategy to achieve improved activity towards oxygen evolution reaction.
1 Seh, W. Z. et al., Science.
2017, 355, eaad4998.
2 Fabbri, E. et al., Catal. Sci. Technol.
2014, 4, 3800–3821.
3 Jiao, Y. et al., Chem. Soc. Rev.
2015, 44, 2060–2086.
4 Lee, Y. et al., J. Phys. Chem. Lett.
2012, 3, 399–404.
5 Paoli, A. E. et al., Chem. Sci.,
2015, 6, 190–196.
6 Hong, T. W. et al., Energy Environ. Sci.
2015, 8, 1404–1427.
Development of Anode Wicks for Liquid Metal Sodium Batteries
Authors: Kim Hwa-Jung , Choi Hanul , Park Inchul , Park Yoon-Cheol , Moon Jiwoong , Yang Choongmo , Sprenkle Vincent , Li Guosheng , Jung Keeyoung 
Published: December 2020

One of the major technical hurdles in developing liquid metal sodium batteries, such as sodium beta-alumina batteries (NBBs), is designing an anode wick which is responsible for facile shuttling of liquid metal and electrons upon cycling. The anode wicks utilize either or both principles of the capillary effect via sophisticated design of its geometry, and the surface tension between the wick and liquid metal via surface treatment of the wick material. It's geometry and surface treatment should be carefully selected because its shuttling capability strongly depends on the travel distance of liquid metal, ranging from tens of microns to over a centimeter, and cell operation temperature especially when the operation current is high.
In this study, different types of anode wicks are devised based on the two principles. The wicks are implemented to one of the most promising liquid metal batteries with Na-NiCl2 chemistry, and their performances are evaluated by varying current densities upon cell cycling.
Hexacyanometalate-Based Redox Couple for High-Efficiency Iron-Chromium Flow Battery
Authors: Jang Ji-Eun , Kim Ryeong-ah , Lee Hyun-Wook 
Published: December 2020

As increasing the importance of electrical grids and utilizing renewable energy sources, large-scale energy storage systems that can effectively store and supply electrical energy have attracted great research attention in recent times. Aqueous based redox flow batteries (RFBs) are promising candidates for large-scale energy storage due to their long cycle life, high safety, and high solubility of a catholyte and anolyte. Also, unlike other battery systems such as lithium-ion batteries, the energy density and power capabilities of RFBs can be decoupled, enabling flexibility for controlling capacity and power, and scalability as an industrial perspective. Iron-chromium (Fe-Cr) RFB is a good candidate for cost-effective systems comparing to all-vanadium RFB, which is well-known as the most developed RFB. However, sluggish Cr3+/2+ redox kinetics and hydrolysis of ferrous ion have become formidable obstacles to achieving high efficiency and stability. In particular, the poor kinetics of chromium ions make the hydrogen evolution reaction more dominant and cause the state of charge of the positive and negative side to being imbalanced.
Herein, we have demonstrated a new RFB system based on hexacyanometalate materials ([M(CN)6]3-/4-, M = transition metal). The cyanide ligands linked through transition metal ions play a role in mitigating the hydrolysis in the aqueous environment and enhance the electrochemical kinetics. We have investigated the stability and electrochemical kinetic information of our redox couples comparing to conventional active materials. The superior kinetics of hexacyanometalate based-redox couples contributed to improving voltage efficiency. Besides, by use of a transition metal oxide type-catalyst on a carbon-felt current collector, this RFB system can achieve higher energy efficiency than that of the pristine carbon-felt electrode, suggesting that the employing catalyst can enhance the electrochemical kinetics of the active materials.
(Invited) Enhancement of Plasmon-Induced Charge Separation through Plasmon Coupling
Authors: Tatsuma Tetsu , Nishi Hiroyasu , Ishida Takuya 
Published: December 2020

Plasmon-induced charge separation (PICS)1,2 involves electron transfer from plasmonic noble metal nanoparticles or compound nanoparticles to an n-type semiconductor such as TiO2. Oxidation reactions involved in PICS are based on a charge accumulation mechanism (Figure a) or a hole ejection mechanism (Figure b).3 The latter enables nanoscale local oxidation at relatively positive potentials.4-7 This can be applied to photoinduced nanofabrication beyond the diffraction limit of light. For instance, chiral plasmonic nanostructures can be prepared by PICS under right or left circularly polarized light (Figure c).8,9 Some other applications of the plasmonic hole ejection will also be mentioned. Enhancement of PICS with hole ejection through plasmon coupling10 and its application to photocatalysis will also be described.
References

Y. Tian and T. Tatsuma, J. Am. Chem. Soc., 127, 7632 (2005).

T. Tatsuma, H. Nishi, and T. Ishida, Chem. Sci., 8, 3325 (2017) [review].

T. Tatsuma and H. Nishi, Nanoscale Horiz., 5, 597-606 (2020) [review].

E. Kazuma, N. Sakai, and T. Tatsuma, Chem. Commun., 47, 5777 (2011).

I. Tanabe and T. Tatsuma, Nano Lett., 12, 5418 (2012).

K. Saito, I. Tanabe, and T. Tatsuma, J. Phys. Chem. Lett., 7, 4363 (2016).

H. Nishi, M. Sakamoto, and T. Tatsuma, Chem. Commun., 54, 11741 (2018).

K. Saito and T. Tatsuma, Nano Lett., 18, 3209 (2018).

K. Morisawa, T. Ishida, and T. Tatsuma, ACS Nano, 14, 3603 (2020).

T. Ishida and T. Tatsuma, J. Phys. Chem. C, 122, 26153 (2018).

Figure 1
Visible Light Hydrogen Production By CdZnS Photocatalysts Prepared in Ethylenediamine Aqueous Solution
Authors: Katsumata Hideyuki , Koguchi Kyosuke , Tateishi Ikki , Furukawa Mai , Kaneco Satoshi 
Published: December 2020

Recently, semiconductor photocatalysts are expected to be a strategy to solve the energy demand and environmental pollution. Many researchers have attention, and have been developed photocatalysts for hydrogen production. Among them, metal sulfides (i.e. CdS, ZnS, MoS2, etc.), metal oxides (i.e. TiO2, Fe2O3, NiOx, RuO2) are regarded as good candidates for the photocatalytic H2 production. CdS is highly important as a photocatalyst because of the low band gap energy (~2.4 eV) and high activity under visible light irradiation for the photocatalytic hydrogen evolution reaction (HER) [1]. However, pure CdS tends to form particle aggregation and inherent photocorrosion, resulting in a higher recombination rate of charge carrier limited its application. One of the effective ways is by combing CdS with ZnS to form CdZnS (cadmium zinc sulfide) [2]. CdZnS has been regarded as a promising photocatalyst, but it has fast recombination of photogenerated electron-hole pairs. Therefore, the photocatalytic hydrogen evolution activity of sulﬁde semiconductor can be signiﬁcantly improved by loading noble metals as cocatalysts to provide active sites for proton reduction.
In this work, we report excellent H2 production performance when PdS, Pt are used as cocatalyst for CdxZn1-xS, which was synthesized via a simple solvothermal synthesis method. The resulting photocatalysts exhibit enhanced hydrogen production from water in 0.25 M Na2SO3 + 0.35 M Na2S as a sacrificial agent.
The crystalline structures of as-prepared CdxZn1-xS were analyzed by XRD. The XRD peaks of Cd0.5Zn0.5S are weaker and broader than those of one prepared in the absence of ethylenediamine during the solvothermal synthesis. These results indicate that the addition of ethylenediamine has a certain inhibitory effect on the growth of the grain of Cd0.5Zn0.5S.
Cd0.5Zn0.5S photocatalyst was selected as optimal one in this photocatalytic activity test. The photocatalytic H2 production over PdS deposited Cd0.5Zn0.5S was enhanced comparing that of pristine Cd0.5Zn0.5S, showing greater about two times. Further, in the presence of dual cocatalysts, namely PdS and Pt, the photocatalytic H2 production was about 2.4 times higher than that of pristine Cd0.5Zn0.5S.

In summary, this work showed that CdxZn1-xS photocatalysts were synthesized successfully by a simple solvothermal method. With ethylenediamine in the solvothermal process, the crystallinity of CdxZn1-xS photocatalysts was lower than that of one prepared by the hydrothermal method. The use of dual co-catalysts, namely PdS and Pt, were effective for the photocatalytic H2 production under visible light.
Lithium-Ion Battery Degradation Mode Diagnostics Using Heat Generation Profiles
Authors: Prosser Ryan , Patel Yatish , Offer Gregory James 
Published: December 2020

As lithium ion cells are used, internal chemical and physical degradation processes occur which negatively impact cell performance. A key issue for battery systems engineers is extending the life of their battery pack which amounts to slowing down the rate of these degradation processes.
The first step in addressing this problem is being able to frequently and accurately diagnose cell degradation. With this knowledge of cell state, it is possible to make better decisions on how to adjust the operating conditions of the battery pack to optimise cell longevity and performance.
Current methods which are capable of accurate quantitative diagnostics employ thermodynamic models parameterised by different degradation modes. These models require very slow discharge rates or galvanic intermittent titration tests (GITT) to obtain the cell open circuit voltage (OCV) and therefore cannot be used in most commercial applications. Other methods which do not require OCV conditions involve an impedance model coupled to the thermodynamic model. This adds computational complexity of the methods as well as incurring an accuracy penalty compared to the thermodynamic models.
We present a novel technique which uses cell instantaneous heat generation rate obtained in operando to quantify the extent of cell degradation. The proposed method provides results comparable to those obtained from thermodynamic models using a model which is no more computationally intense. The method also decouples the thermodynamic and kinetic effects of degradation allowing for a full diagnosis to be obtained more accurately and in a fraction of the time compared to alternative methods.
With this powerful and simple method, a battery management system would be able to make better and more frequent adjustments to its cell’s operating conditions for optimizing both longevity and performance.
Insights into the Reversible Redox Pathways in Lithium-Sulfur Batteries By in Situ AFM-SECM Coupled Raman Spectroscopy
Authors: Thangavel Naresh kumar , Mahankali Kiran , Arava Leela Mohana Reddy 
Published: December 2020

Among many emerging energy storage systems, lithium-sulfur (Li-S) is the most sought-after technology due to its high energy density (2600 Wh/kg) and low cost.(1) However, its performance is guided by highly complex and non-equilibrium conversion reactions of several sulfur intermediates, known as lithium polysulfides (LiPS), along with solid-liquid-solid phase transformations at the cathode surface. Such Li-S batteries often face formidable challenges like rapid capacity fade, sluggish reaction kinetics, short cycle life, and poor coulombic efficiency(2). In spite of some success in mitigating these issues by employing a variety of cathode surface modifications(3, 4), the fundamental understanding of LiPS reaction pathways towards discharge end-products and their relation to the cathode surface are still not well established.
It is commonly believed that the morphology, composition and physio-chemical characteristics of the discharge products can be closely correlated to the deteriorating performance issues like internal resistance buildup and capacity fade in Li-S cell(5-7). Herein, we provide mechanistic perspectives of the substrate guided reaction pathways of LiPS and their correlation to redox activity of discharge end products using in situ atomic force microscopy-based scanning electrochemical microscopy (AFM-SECM) coupled Raman spectroscopy at a high spatiotemporal resolution. With a detailed spectro-electrochemical and morphological mapping, we decipher the substrate-dependent charge/discharge end product’s formation and their effect on redox processes in the subsequent cycles.
References:
1. G. Bruce, S. A. Freunberger, L. J. Hardwick and J. M. Tarascon, Nature materials, 11, 19 (2012)
2. Manthiram, Y. Fu and Y. S. Su, Accounts of chemical research, 46, 1125 (2012).
3. Babu, N. Masurkar, H. Al Salem and L. M. Arava, J Am Chem Soc, 139, 171 (2017)
4. Pang, D. Kundu, M. Cuisinier and L. Nazar, Nature communications, 5, 4759 (2014)
5. Yan, X. Liu and B. Li, Advanced Science, 3, 1600101 (2016)
6. Diao, K. Xie, S. Xiong and X. Hong, Journal of The Electrochemical Society, 159, A1816 (2012)
7. Y. Lang, Y. Shi, Y. G. Guo, D. Wang, R. Wen and L. J. Wan, Angewandte Chemie International Edition, 55, 15835 (2016).
Probing Electrode Electro-Chemo-Mechanical Coupling Behaviors through Mechanical Cyclic Voltammetry (mCV)
Authors: Tsai Wan-Yu , Balke Nina 
Published: December 2020

Electrode deformations during charging and discharge process are directly related to the power performance and cyclability of the energy storage devices. Understanding the electrode deformation and changes in mechanical responses during electrochemical events and their impact on devices’ performance is crucial for achieving high power and high energy storage devices. In-situ atomic force microscopy (AFM) is well suited to tackle this task as it allows tracking local sub-nanometer volume changes and other mechanical responses. With a spatial resolution of tens of nanometer, this approach is capable of mapping the electro-chemo-mechanical behavior under the conditions close to the device operation and access information about local redox mechanisms.
In this work, the electro-chemo-mechanical coupling behaviors of different pseudocapacitive materials was studied via in-situ AFM. The concept of mechanical cyclic voltammetry (mCV) curves was developed, and the relationship between electrochemical current and strain were investigated with simplified models. The results revealed that multiple ion-intercalation processes with different mechanical responses are involved during electrode cycling. The mechanical CV mapping highlighted the local heterogeneity and showed that the charging mechanisms varied across the electrode. These local variations could be further corelated to local morphology, crystal orientations or chemical compositions. Besides providing information of redox heterogeneity, the mechanical CV methodology allows us to circumvent the common issues that are often encountered in the global electrochemical characterizations, for example cell resistance and unwanted parasitic reaction.
The work was supported by the Fluid Interface Reactions, Structures and Transport (FIRST), an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences. Measurements were performed at the Center for Nanophase Materials Sciences (CNMS), which is sponsored at Oak Ridge National Laboratory by the Scientific User Facilities Division, Office of Basic Energy Sciences.
Towards Quantifying Capacity Losses Due to Solid Electrolyte Interphase Evolution in Silicon Thin Film Batteries
Authors: Steinrück Hans-Georg , Cao Chuntian , Veith Gabriel M. , Toney Michael F 
Published: December 2020

To better understand failure mechanisms in lithium-ion batteries (LIBs), it is imperative to quantify the capacity fading contributions from active material loss and solid electrolyte interphase (SEI) growth. However, these two contributions are indistinguishable in traditional electrochemical measurements. In this study, we used a model system in combination with (1) precision measurements of the overall Coulombic efficiency via electrochemical experiments and (2) X-ray reflectivity (XRR) measurements of the active material losses. The model system consisted of a 515 Å thick amorphous silicon (a-Si) thin film on silicon carbide in a half-cell geometry using a carbonate electrolyte with LiPF6 salt. Schematics of the cells used in operando XRR and precision electrochemistry measurements are shown in Fig. (a) and (b) respectively.
Specifically, we used surface/interface sensitive operando XRR to monitor the a-Si/LixSi thickness during (de)lithiation in order to quantify the capacity fading due to active material loss. Combined with electrochemical analysis, we quantified the capacity loss originating in SEI growth during each cycle (Fig. (c)). We have found that SEI continues to grow with cycling, and the SEI thickness is dependent on the time spent at low potentials (Fig. (d)). The continued SEI growth results in increasing overpotentials due to increased SEI resistance, which leads to a lower extent of lithiation when the cut-off voltage is reached. Finally, we extracted a proportionality constant for SEI growth following a parabolic growth law. Our results are in fair agreement with the capacity losses observed in full cell systems.
We envision that the proposed methodology can be used as a qualitative measure of the ion transport properties of the SEI. The model-based approach allows for quantitative determination of lithium ion loss mechanisms in LIBs by separately tracking lithium ions within the active materials and will aid in developing ways to reduce parasitic losses.

Figure 1