Additive Manufacturing and Electrochemistry

The Electrochemical Society Interface • Spring 2016 • www.electrochem.org 61 A lthough there has been tremendous growth in the capabilities of additive manufacturing in recent years, its roots go back hundreds of years. In many ways, some of the first electrochemists were also the first practitioners of additive manufacturing when they demonstrated that a low cost base metal could be coated with a premium finish in a conformal manner at room temperature in minutes. The first electrodeposition experiments date back over 200 years when Luigi Valentino Brugnatelli first electrodeposited gold upon silver, at first for academic experiments, and then for commercial application. Since that time, scaled commercial applications of electrodeposition have been critical to many aspects of science and engineering. More recently, the emergence of affordable, commercially-available 3D printers capable of depositing electrically insulating media via extrusion printing and additive photocuring methods have offered a wonderful complement to traditional electrodeposition, enabling both rapid prototyping and precise, high-throughput freeform manufacturing. In this issue of Interface we explore some of the benefits and opportunities that modern additive manufacturing methods offer for the practice of electrochemical analysis, engineering, and energy storage. In the first paper of this issue, Robert B. Channon, Maxim B. Joseph and Julie V. Macpherson, demonstrate the use of low cost additive manufacturing based on stereolithography, to create (micro) fluidic flow cells at scales that are either difficult or impossible to achieve with traditional methods. The ability to create high resolution, customized flow cells allows researchers to study fluid transport and electrochemical phenomena, as well as enabling highly accurate electroanalytical sensing with small analyte volumes and high throughput for a wide range of applications. With the methods described in this section, (micro)fluidic analysis systems can go from a sketch to a practical system within an afternoon, and that same device can be effortlessly replicated with slight variations in device geometry to create an array of parallel experiments. Trevor Braun and Dan Schwartz provide an article exploring the intersection of freeform patterning and electrodeposition with the use of software reconfigurable scanning electrodeposition cells. In traditional electrodeposition, the volume of the electrolyte is far larger than that of the deposited materials. This article shows that when the ratio is inverted, the small electrolyte volume can be used to direct growth and structure in exceptional ways without the limitations of traditional maskor stamp-based patterning techniques. Another exciting development that is discussed in this article is the use of bipolar electrochemistry to perform localized freeform electrodeposition without an electrical contact to the substrate, a development that greatly expands the utility and throughput of electrodeposition-based additive manufacturing. The final paper by Corrie Cobb and Christine Ho demonstrates how additive manufacturing and rapid prototyping methods can improve the performance and the range of applications of electrochemical energy storage. Given the particle/composite structure of most secondary storage devices, the materials selection available is largely the same as those for traditional batteries. A device designer, using the methods described here, can embed a battery optimized not only between power and energy density, but also between conformable, flexible, and stretchable factors. Critical to this new paradigm in product design is a deep level of interaction between the design of the battery, powertrain, and the device itself. With modern rapid prototyping methods, all three components can be iteratively edited and optimized with unprecedented speed. Beyond device integration, these new manufacturing methods for batteries may improve batteries for traditional applications: Rational integration of separator and electrode can allow for thicker electrodes at a given power density, improving cost per unit energy and energy density at a system level. Taken together, these three pieces provide an excellent overview of how recent advances in electrochemical engineering and electroanalytical tools can be merged with modern prototyping tools to create new opportunities for sensing, device production, and electrochemical energy storage. However, we believe that these examples are only the tip of the iceberg, and that the integration of electrochemical engineering and additive manufacturing will only accelerate in the years to come. While these articles are not meant to be comprehensive reviews of additive manufacturing, we hope that they inspire Interface readers to learn more about these powerful new tools and invent novel ways that additive manufacturing can advance electrochemistry, and that electrochemistry can advance additive manufacturing. Electrochemical engineering, the first in additive manufacturing and rapid prototyping, still has much to contribute to this growing field. In the spirit of "open access" knowledge sharing, DS has recently created a website (echem.io) where users can share (via GitHub) 3D cad design files and other open source hardware and software tools that were generated as a part of electrochemistry-focused research and development efforts. We hope you check it out!