By: Yanbo Qi, Taejin Jang, Venkatasailanathan Ramadesigan, Daniel T. Schwartz, and Venkat R. Subramanian

This article refers to a recently published open access paper in the Journal of the Electrochemical Society, “Is There a Benefit in Employing Graded Electrodes for Lithium-Ion Batteries?”

The contour plot for the resistance of a 2-layer graded cathode with different porosity combinations. Layer 1 is the layer near the separator, and layer 2 is near the current collector. The blue dot represents the point of minimum resistance (5.1164 Ω-cm²) for the 2-layer graded electrode. The diagonal line of ε₁ = ε₂ is equivalent to the single layer uniform case. The intersection point (5.3510 Ω-cm²) of the diagonal line with the contour is the optimal point for single layer design. The hatched area inside the contour represents the search space for 2-layer graded electrode design with resistance no bigger than the uniform optimal case. By introducing the 2-layer graded electrode structure, the feasible region changes from a point to a reasonably sized area. With the extra freedom in design, more objectives can be considered without resulting in an electrode with higher resistance.

Functionally graded materials have been widely developed in various fields, including the solid oxide fuel cells. However, its application in batteries is less common. Using simulation and optimization, both benefits and negligible improvement have been reported in the literature, depending on how the problem is formulated. The cases where people saw little impact by incorporating graded electrode design are cases where only one design objective, the energy density, is considered. While the cases where bigger improvement was reported are either compared to a base case as opposed to the best single layer case or considered with more than one design objectives.

In a recently published paper, we shared our opinion on this controversial topic. We applied two different optimization approaches to the secondary current distribution porous electrode model to confirm the optimal profiles acquired, and to facilitate the multi-objective optimizations later on. When looking at a single objective, minimizing the overall electrode resistance, and comparing with the optimal single layer case, only 4-6% modest reduction can be achieved. Therefore, we agree with the conclusion that for single objective optimization, graded structure does not make a big difference.

However, electrode design is not a simple matter where only one goal is desired. One of the powerful features of battery modeling is that it can give us insights on battery’s internal status, which is difficult to get otherwise. In our paper, we minimized the value and distribution of activation overpotential inside the electrode along with the overall resistance. What we discovered is that even though doing graded electrode cannot reduce the overall resistance much, with the extra design freedom in porosity distribution, the search space increased dramatically in the 2-layer graded electrode case compared to the single uniform layer case. The extra design space is very important in multi-objective optimization, allowing us to take into account other design considerations, including controlling the internal status. We believe that the value of graded electrode lies in the enlarged search space for additional design considerations, not just the improvement in a single objective.

Aligned with ECS’s commitment to Free the Science, we also believe that open access facilitates collaboration and speeds up scientific advancement. We have developed a free electrode design tool on our website (http://depts.washington.edu/maple/Design.html). This open access executable code is readily runnable on any Windows computer without extra software requirement. The tool allows users to change model parameters, thus can accommodate any electrode chemistry. Detailed explanation and instructions can be found on the webpage. We hope that this tool can help the community to achieve better battery performance.

Submit your manuscripts to the Journal of The Electrochemical Society (JES) Focus Issue on Processes at the Semiconductor-Solution Interface by October 22, 2017.

This issue of JES will address the most recent developments in processes at the semiconductor-solution interface including etching, oxidation, passivation, film growth, electrochemical and photoelectrochemical processes, water splitting, electrochemical surface science, electroluminescence, photoluminescence, surface texturing, and compound semiconductor electrodeposition, for photovoltaics, energy conversion and related topics.

It will include both invited and contributed papers on both fundamental and applied topics of both bulk and nanoscale materials. The following areas are of particular interest:

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Stephen Maldonado is an associate professor at the University of Michigan, where he leads a research group that focuses on the study of heterogeneous charge transfer processes relevant to the fields of electronics, chemical sensing, and energy conversion/storage technologies. He was recently reappointed as an associate editor for the Journal of The Electrochemical Society (JES) in the area of physical and analytical electrochemistry, electrocatalysis, and photoelectrochemistry.

ECS: When did you become an ECS associate editor? What made you pursue an editorial role at ECS?

Stephen Maldonado: I started my time as an ECS associate editor in 2014. I pursued the opportunity for two different reasons. The minor reason was that I was genuinely curious about the “sausage making” process of accepting/rejecting a paper. That is, as an author, I had prepared and submitted plenty of papers but I had little idea about the other side of it. I had reviewed plenty of papers, too, but how those reviews factored into the final fate of the submission was a mystery.

The major reason, though, is that electrochemistry has been a principal aspect of my adult life. I got into science because, at a fundamental level, I thought electrochemistry was cool. Accordingly, my interests were aligned with the ECS at the start and it has been a major influence on my professional development. After getting tenure, I felt the time was right to give back to this community. So when I was asked to consider the position, I jumped at the chance.

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Minhua Shao is an associate professor at the Hong Kong University of Science and Technology, where he leads a research group pursuing work in advanced material and electrochemical energy technologies. Shao’s current work focuses on electrocatalysis, fuel cells, lithium-ion batteries, lithium-air batteries, CO₂ reduction, and water splitting. Shao was recently named an associate editor of the Journal of The Electrochemical Society in the area of fuel cells, electrolyzers, and energy conversion.

The Electrochemical Society: What do you hope to accomplish in your new role as associate editor of the Journal of The Electrochemical Society?

Minhua Shao: As an associate editor, I hope to accelerate the manuscript handling process by identifying suitable reviewers and making fair decisions. I also hope to promote the journal at conferences and among peers, attracting high-quality manuscripts.

ECS: How has scholarly publishing evolved throughout your career?

MS: Scholarly publishing has changed significantly in the past two decades. Now researchers have many more choices on which journals to publish their results. The adoption of the so-called impact factor in assessing the quality of journals/papers has misled the scientific community. More seriously, there is a trend that scholarly publishing is more of a business than a platform for sharing research results.

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The Journal of The Electrochemical Society (JES) Focus Issue on Oxygen Reduction and Evolution Reactions for High Temperature Energy Conversion and Storage is now complete, with 16 open access papers published in the ECS Digital Library.

“In this new and exciting era of distributed electricity generation, the modularity (sub-kW to 100 kW systems) with minimal efficiency loss at small scales makes solid oxide fuel cells (SOFCs) an exciting energy conversion technology,” the authors say in the focus issue’s preface. “This focus issue presents some of the latest research in understanding fundamental mechanisms of ORR and OER, and highlights new materials and concepts to achieve both greater performance and long-term durability.”

Read the full JES Focus Issue on Oxygen Reduction and Evolution Reactions for High Temperature Energy Conversion and Storage.

ECS would like to thank JES technical editor Tom Fuller and this focus issue’s guest editors Sean Bishop, Ainara Aguadero, and Xingbo Liu.

The Journal of The Electrochemical Society (JES) Focus Issue on Mathematical Modeling of Electrochemical Systems at Multiple Scales in Honor of John Newman is now available online, with 72 open access papers published in the ECS Digital Library.

“This focus issue of the Journal of The Electrochemical Society is devoted to the mathematical modeling of electrochemical systems across multiple scales,” the authors say in the focus issue’s preface. “It is dedicated to the work of Professor John Newman from UC Berkeley, who helped establish the field of modeling of electrochemical systems, and is aligned with a previous focus issue and regular symposium on multiscale modeling for electrochemical systems at ECS biannual meetings.”

Newman is a renowned battery researcher and developer of “The Newman Method” — a sophisticated approach to mathematically analyzing complex electrochemical problems. He clarified the physicochemical laws that govern the behavior of electrochemical systems and demonstrated how to use these laws to correctly formulate and solve problems associated with batteries, fuel cells, electrolyzers, and related technologies. He is the author of the book Electrochemical Systems.

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In its first Science for Solving Society’s Problems Challenge, ECS partnered with the Bill & Melinda Gates Foundation to leverage the brainpower of electrochemists and solid state scientists, working to find innovative research solutions to some of the world’s most pressing issues in water and sanitation. A total of seven projects were selected, resulting in a grand total of $360,000 in funding.

The researchers behind one of those projects recently published an open access paper in the Journal of The Electrochemical Society discussing their results in pursuing a single-use, biodegradable and sustainable battery that minimizes waste. The paper, “Evaluation of Redox Chemistries for Single-Use Biodegradable Capillary Flow Batteries,” was published August 18 and authored by Omar Ibrahim, Perla Alday, Neus Sabaté, Juan Pablo Esquivel (pictured with prototype at right), and Erik Kjeang.

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The journal impact factors (JIFs) for 2016 have been released, and ECS is pleased to announce that the JIFs for the Journal of The Electrochemical Society (JES) and the ECS Journal of Solid State Science and Technology (JSS) have both risen by 8%.

The JIFs, published in the Journal of Citation Reports (formerly published by Thomson Reuters, now called Clarivate Analytics), are a long-established metric intended to evaluate the relevancy and importance of journals. A journal’s JIF is equivalent to the average number of times its articles were cited over the course of the prior two years.

From 2015 to 2016, the JIF of JES increased from 3.014 to 3.259, and the JIF of JSS climbed from 1.650 to 1.787. These increases mark a continuing trend of growth for both journals.

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Brett Lucht is a professor of chemistry at the University of Rhode Island, where his research focuses on organic materials chemistry. Lucht’s research includes the development of novel electrolytes for lithium-ion batteries and other efforts to improve the performance of electrolytes for electric vehicles. Lucht has recently been named associate editor for the Journal of The Electrochemical Society.

The Electrochemical Society: What do you hope to accomplish in your new role as associate editor?

Brett Lucht: I hope to improve the prestige of the journal. While the Journal of The Electrochemical Society is the oldest journal of electrochemical science, competition from other journals has become fierce.  The Electrochemical Society is the largest scientific organization focused on electrochemistry and ECS meetings are very well attended. Thus publishing electrochemical research in the Journal of The Electrochemical Society should be the most prestigious place to publish.

ECS: Why should authors publish in ECS journals?

BL: The Journal of The Electrochemical Society has been in continuous production since 1902—115 years. While many new journals come and go, they are frequently focused on narrow topics which fluctuate in importance.  Publications in the Journal of The Electrochemical Society will last the test of time.  In my area of research, lithium-ion batteries, many new journals are publishing research in this area. However, many of the fundamental research articles providing the foundation for this field were published in the Journal of The Electrochemical Society.

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ECS believes that the key to sustainability is the ability to adapt. For over 115 years, ECS has been committed to publishing high quality, peer-reviewed research at the cutting edge of innovation.

But the demands of the research arena are always changing. As the scientific community develops new needs out in the field, so must ECS—as a leading nonprofit publisher—develop new avenues and more inclusive platforms for publication and dissemination.

To best accommodate the needs of contemporary scientific research, ECS’s journals, the Journal of The Electrochemical Society and the ECS Journal of Solid State Science and Technology, are open to article submission types beyond that of the standard-issue research paper. As of 2017, ECS accepts journal submissions of five different types.

Whether you’re an author, an editor, or a reader of ECS publications, it’s beneficial to be familiar with the five ECS journal article types.

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