(Invited) Natural Fiber Welded Composites: Electrodes and Capacitors

Natural fiber welding (NFW) is a method whereby solvent blends and process conditions are tailored to selectively swell and mobilize the biopolymers of fibrous, natural materials for functional (chemical and physical) modification. 1-4 For example, careful control of solvent to substrate ratio, solvent composition (efficacy), as well as the time, temperature, pressure, and location of solvent exposure results in robust composites composed of fibrous substrates that are fused without glues or resins. The biopolymers within the cores of individual fibers may be demonstrated to retain their native structures and thus functionalities. In addition to unique fiber blends, other materials such as conductive carbons, magnets, fire retardants, et cetera may be incorporated during processing to yield highly functional composites that are sustainably produced and exhibit low embodied energy. In this presentation, we will discuss NFW processes to create flexible carbon-containing yarns for wearable supercapacitor applications. In particular, repeatable, scalable processes that generate composites that perform on par with similar state of the art devices reported in the literature. Given that these composites are based on truly ‘green’ cellulosic and lignocellulosic substrates (cotton and bamboo) and utilizing a nonfluorinated binder (cellulose from cotton), we believe this to be a significant breakthrough for the prospects of wearable energy storage. 5-8 In addition, we will discuss the prospects for large scale nonwoven bio-based electrodes produced from inexpensive agricultural wastes and suitable for any number of important applications (e.g., filtration of pollutants from air and water). Acknowledgements : Portions of this work were funded by the Air Force Office of Scientific Research. Any opinions, findings, conclusions or recommendations expressed in the material are those of the authors and do not necessarily reflect the views of the U.S Navy or U.S Air Force. K. Jost acknowledges support from the DoD National Defense Science and Engineering Graduate (NDSEG) Fellowship. References: (1) L. M. Haverhals, W. M.Reichert, H. C. De Long, P. C. Trulove, Macromol. Mater. Eng. , 2010 , 295 , 425-430. (2) L. M. Haverhals, H. M. Sulpizio, Z. A. Fayos, M. A. Trulove, W. M. Reichert, M. P. Foley, H. C. De Long, P. C. Trulove, ECS Transactions , 2010 , 33 , 79-90. (3) L. M. Haverhals, H. M. Sulpizio, Z. A. Fayos, M. A. Trulove, W. M. Reichert, M. P. Foley, H. C. De Long, P. C. Trulove, Cellulose , 2012 , 19 , 13-22. (4) L. M. Haverhals, L. M. Nevin, M. P. Foley, E. K. Brown, H. C. De Long, P. C Trulove, Chem. Commun. , 2012 , 48 , 6417-6419. (5) Simon, P. & Gogotsi, Y. Nature Materials , 2009 , 7 , 845-854; (6) Jost, K. et al. Energy and Environmental Science 2011 , 4 , 5060-5067. (7) Jost, K. et al. Energ Environ Sci., 2013 , 6 , 2698–2705. (8) K. Jost, D. P. Durkin, L. M. Haverhals, E. K. Brown, M. Langenstein, H. C. De Long, P. C. Trulove, Y. Gogotsi, G. Dion, Adv. Energy Mater. , 2015 , 5, 1401286.