Dr. Orlando Rios
Oak Ridge National Laboratory (ORNL)
Friday, January 17, 2014
Science and Engineering Research Facility (SERF)
"Lignin-Based Energy Storage Materials: Nature Provides the Enabling Microstructures
A key barrier to widespread adoption of electric vehicles is the limited range of currently available models. Overcoming this barrier will require non-incremental improvements in the specific energies and energy densities of battery packs without increasing cost.
Dr. Orlando Rios and team address this predicament by demonstrating a novel approach to energy storage that combines low-cost materials and scalable manufacturing methods to yield high performance electrodes. Lignin is key to this concept; it is the second most abundant naturally occurring biopolymer and on average comprises 18-35% of wood by weight. This low-cost, biomass-derived material was selected as an alternative precursor for the production of free standing carbon fiber anodes for use in Li-ion batteries.
In this seminar, Rios reports the direct manufacturing of high capacity carbon/silicon based composite fiber electrodes that are produced via a flexible low-cost melt processing route to yield low-cost stable silicon particles embedded in electrochemically active and electronically conductive carbon fiber derived from lignin precursor material. In response to the Department of Energy's "EV Everywhere" initiative and general goals, Rios and group focused on a cost-centric approach to battery manufacturing by demonstrating a new technology designed to be compatible with well-established industrial scale manufacturing methods using only low-cost materials.
The synthesis, processing, and performance of a low cost monolithic battery electrode produced entirely of natural and renewable resources are reported. This anode material exhibits tunable electrochemical performance suitable for both high power and high energy applications. Rios and team developed a synthesis method that directly results in electrically interconnected three-dimensional architectures where the carbon framework functions as current collector and lithium insertion material, eliminating the extra mass and expense of inactive materials in conventional designs. Fibrous carbon electrode materials were produced from solvent extracted lignin using scalable melt processing technology and thermal conversion methods.
The resulting free standing electrodes exhibited comparable electrochemical performance to commercial carbon-based anodes at a fraction of the materials and processing costs. The team applied these methods to fabricate a next-generation Si+C architecture using low cost, industrially scalable materials and process technologies. The combination of high capacity with enhanced electrochemical and chemical stability was achieved by embedding micron-scale Si particles in binder-free, lignin-based carbon fibers (LCF) to form composites that are entirely made of active materials having at least semi-coherent grain boundaries, from which three-dimensional monolithic electrode architectures can be made.
Battery tests show capacity in excess of 2000 mAh/g for 20 cycles and 500 mAh/g for 50 cycles. The Coulomb efficiency of these anodes has been measured in excess of 99.5%.
Dr. Orlando Rios received his PhD from the University of Florida in materials science and engineering. He has a broad technical background that includes alloy development in aluminum, NiTi based shape memory alloys, titanium aluminides, steels, cast irons and magnesium.
Rios also has a background in electrochemical processing of semiconductors. He has technical interest in the understanding of the structure of materials and how to attain enhanced material properties through alloy design and structural modification via advanced processing.
Currently, he is a Alvin Weinberg Fellow and a group member of Oak Ridge National Laboratory's materials processing group with a focus on high temperature magnetic processing and synthesis. He is working on advancing the understanding of energy related materials and energy efficient processing centered on industrially transferable technologies. Rios is also part of a team working on the development of novel magnetocaloric materials through combinatorial studies.