This PFI: AIR Technology Translation project focuses on translating the science and technology of unique multifunctional ultrananocrystalline diamond (UNCD) film (coating) technology into superior energy storage cells and solutions that fill the performance, life-cycle, and production readiness gap evident in conventional battery applications. The collective goal is to produce a commercially viable path to the next generation of Li-ion batteries (LIB) and a new generation of thermal Li-Sulfur (TLS) batteries. The translated science and technology of UNCD-based LIB and TLS have the following unique features: i) high performance anodes based on electrically conductive UNCD-coated metal anodes to increase the battery lifetime by at least 10x with respect to current technologies, ii) UNCD-based membranes for Li+ ions transport with at least 10x higher resistance to battery environmental and chemical attacks than for current batteries, and iii) UNCD films as extremely chemically resistant coatings for the battery inner walls case to substantially lower the cost, extend cells' life-cycle, and improve the economic viability of the end product. Currently, much more expensive metals would be required to survive the targeted x10 longer life time (given exposure to the harsh environment of the LIB and TLS batteries). This PFI AIR project intends to deliver a TLS battery that has a potential volumetric energy density of 2,600 Wh/l with a theoretical specific energy density of 2,500 Wh/kg, which is at least x10 superior performance to current battery technologies. The state-of-the-art for cathodes and anodes (two critical components) for this couple currently features a theoretical volumetric energy density of 2,125 Wh/l and a theoretical specific energy density of 597 Wh/kg. The resulting TLS approach will provide 22% improvement in volumetric energy density and ~400% improvement in specific energy density over existing secondary LIB technologies, when compared to the leading competing LIB science/technology from manufacturers in this market space. The project accomplishes its objectives by developing: i) boron-doped UNCD (B-UNCD) and nitrogen-grain boundary incorporated (N-UNCD) coated metallic electrodes (e.g, tungsten (W), titanium (Ti), or W-coated Cu) to determine which is the best anode material to insert in the new generation of LIB and TLS batteries, ii) the best approach between a patented chemical etching processes from Advanced Diamond Technologies (ADT) and UNCD-coated Si-based or anodic aluminum oxide (AAO) membranes used as templates to produce 10x more chemically robust UNCD-based membranes than current battery membranes, and iii) chemically resistant UNCD coating for the inner walls of the battery metal case to make it possible to use a less expensive metal material as opposed to currently used molybdenum that is both expensive and chemically less resistant. A prototype coin-type battery will be demonstrated as a proof-of-concept of the novel UNCD-based LIB and TLS battery technologies for defibrillators/pacemakers, cell phones, and computers. The new UNCD-based battery technology will be scalable to produce larger batteries for larger systems such as car batteries. The partnership engages researchers from the University of Texas at Dallas (Materials Science and Engineering Department), who will provide N-UNCD coatings for the battery anodes and UNCD-coated membranes based on the Si and AAO templates. The industrial and commercialization partner is Advanced Diamond Technologies (ADT), a company currently expanding the commercial application of thin smooth diamond. ADT will provide the expertise for developing the B-UNCD films as alternative electrically conductive coatings for battery anodes, as described above. In addition, ADT will provide expertise on customer identification, engagement and commercialization, as well as manage production of the diamond coated battery components (pre-integration) and public introduction of the first LIB/TLS batteries in the market. The infrastructure is already in place in ADT facilities to translate the UNCD coating science/technology along a path that will result in a competitive commercial reality for a new generation of LIB and TLS batteries with potentially 10x better performance than current batteries. The potential economic impact includes domestic production of high energy density cells expected to become viable in the next five years, and will re-engage the US as a competitive fixture in the batteries market space with key, targeted market segments in medical devices/systems, mobile communication devices, computers and many other systems requiring long life low cost batteries. The societal impact, long term, will be in the form of i) at least 10x smaller/longer life for medical implants (i.e., defibrillators/pacemakers), which will impact positively the quality of life of people requiring these devices, and ii) longer life/smaller batteries to power more efficient cell phones, portable computers, and other electronic devices.
NSF PFI Award # 1343461 Outcomes The outcomes of the PFI/AIR Technology Translation project, titled "Ultrananocrystalline Diamond (UNCD) Coating Technology for Integrated Electrode-Membrane-Inner Wall Coating of Case for Robust/Reliable Commercial Li-Sulfur Batteries" were the following: Development of a unique corrosion resistant electrically conductive coating of diamond, named nitrogen incorporated ultrananocrystalline diamond (N-UNCD), in the form of a film with grain sizes of 5-10 nm (0.0000003-5 cm), and nitrogen incorporated into the gain boundaries and providing electrons for conduction. The N-UNCD films were grown on natural graphite/copper anodes (see Fig. 1 attached in the outcomes section) used in commercial Li-ion batteries, which exhibit chemical corrosion by the Li environment. The UNCD coating protects the NG/Cu anodes from corrosion, enabling an order of magnitude longer life with appropriate energy capacity (see Fig. 2A attached in the outcomes section), due to elimination of chemical attack and degradation induced by the Li environment (see Fig. 2B attached in the outcomes section). The N-UNCD films were grown using a microwave plasma chemical vapor deposition technique featuring insertion of a mixture of argon (Ar), methane (CH4), nitrogen (N2) gases into a chamber where air was evacuated with appropriate pumps to make vacuum. Microwave power crack the CH4 molecule producing C-based molecules (C2 dimers and CHx (x=1,2,3) molecules upon landing on the surface of the anode, heated to temperature in the range 500-700 ?C, induce the growth of the N-UNCD coating. Development of corrosion resistant UNCD coatings, using hot filament chemical vapor deposition (HFCVD), to cover the inner surface of stainless steel (SS) metal used for fabrication of cases that contain the Li-ion batteries components. The HFCVD process involves inserting a mixture of (Ar), methane (CH4), and hydrogen (H2) gases into a chamber where air was evacuated with appropriate pumps to make vacuum. The CH4 molecules break upon impacting on an array of tungsten filaments heated to about 2000 ?C by passing a current though them as in the light bulbs. A unique outcome for this part of the project was the discovery that by coating the SS surface with an oxide film (only 30 nm thick), extensively used in the microelectronic industry, we were able to suppress diffusion of hydrogen, from the UNCD growth process, into the SS bulk, which make the metal brittle due to reaction of hydrogen atoms with SS atoms, which induced hydride formation that produce the brittleness, thus breaking of the metal. Therefore, UNCD can be grown on SS metal for LIBs cases, using the novel oxide interface layer to keep the SS metal flexible after coating with UNCD (see Fig. 3 attached in the outcomes section). A patent is being submitted. Development of corrosion resistant metal membranes for Li-ion batteries coated with UNCD. The process involves coating with UNCD films flexible tungsten (W) membranes fabricated using photolithography and reactive ion etching (RIE) processes. The coating enables to close the opening of the W membrane holes to the appropriate dimensions for Li ions filtration. The novel N-UNCD-coated anodes and cathodes, UNCD coated metal-based membranes and inner walls of battery cases (see Fig. 4 attached in the outcomes section) may enable the next generation of batteries with ≥ 10x longer life and much smaller dimensions than current LIBs and future TLSs. The R&D performed under the NSF PFI funded program has a great potential for enabling a new generation of miniaturized defibrillators, pacemakers, neural stimulation systems, and smaller mobile communication and electronic devices, powered by batteries with much reduced recharging requirements, which can make a major impact in people’s way and quality of life.
