Domestic Halloysite-Derived Silicon as a Low-Cost High -Performance Anode Material for Li-Ion Batteries

Problem to Be Addressed To meet performance and cost targets for electric vehicles, substantial improvement is still required in lithium-ion batteries. A low-cost, high-capacity silicon anode will greatly aid in this effort, but current methods for generating functional nano-silicon for anodes use expensive metallurgical, templating, gaseous, or other top-down engineering processes. Objective and Approach This project proposes to use the naturally occurring clay mineral halloysite as a raw material for producing nano-porous, nano-sized silicon for use in lithium-ion batteries. The largest known reserves of this mineral at high purity are found in Utah and can be mined and processed at low cost because the native structure of the mineral is ideal for battery use. Phase I Activities The team, consisting of a small business, university, and national laboratory, extracted, purified, processed, and tested halloysite-derived silicon for battery use. Process improvements and scaling considerations were identified. Material characterization was performed. Testing indicated that halloysite- derived silicon has strong potential as a high-performance anode material. Phase II Activities Further scaling and process control will require adjusting reaction conditions and chemical compositions to achieve optimal cycling and capacity performance of the halloysite-derived silicon material. Extensive step-by-step characterization of material evolution through the entire process will be performed. The production process will be designed and transferred to the small business for additional scale-up. Material will be provided to potential customers for evaluation. Commercial Applications and Other Benefits Customers of this technology and product will be battery manufacturers that supply the cells needed for electric vehicles. Large-scale, economical production of high-performance silicon anode material will allow significant public benefits. As the cost of batteries decrease, the cost of electric vehicles will be reduced, making affordable, emission-free transportation available to the public.