SBIR-STTR Award

This Small Business Innovation Research Phase I project proposes to develop and commercialize new types of silicon nanowire anodes which may be used to safely store large amounts of lithium for many types of lithium batteries. The key innovation involves unique functionalization and integration methods that enable nanowire anodes to be cycled reversibly for thousands of cycles without mechanical failure, agglomeration, or deleterious side reactions. Silicon nanowires will be fabricated via electroless etching, and chemically or electrochemically functionalized to improve their performance and capacity retention in a lithium-ion battery. The objective of this work is to develop novel silicon composite anodes that may undergo over 200 deep cycles with capacities of at least 1000 mA.hg-1. The broader impact/commercial potential of this project is to develop high capacity anode rechargeable lithium batteries with capacities of over 1000 mA.hg-1, which represents approximate doubling of cell capacity without a significant change in manufacturing or cost. There is a critical need for high energy density rechargeable batteries for next generation hybrid vehicles and fully electric vehicles. In a recent report, the U.S. Department of Energy pointed out that the primary obstacles to the widespread introduction of lithium-based batteries for electric vehicles are the relatively low specific energy and the relatively high cost per kWh. The proposed integration and surface engineering methods will address these problems allowing the safe storage of lithium in silicon anodes for current and future generations of lithium batteries.

This Small Business Innovation Research Phase II project proposes to develop and commercialize surface-engineered silicon anodes for use in lithium-ion batteries. Silicon has a ten fold greater charge capacity than graphite but its practical use as an anode material is hindered due to the mechanical problems associated with lithiation cycles (cracking, pulverization) and unwanted chemical reactions at silicon surfaces. Electrochemical Materials (EM) has developed wet surface functionalization methods enabling silicon nanoparticles to be reversibly cycled without mechanical failure or deleterious side reactions. In this work, EM will develop the surface chemistry and integration methods to create anodes for tablet-size (4000mA?h) lithium- ion batteries. EM will develop a scalable manufacturing process and demonstrate batteries with surface-engineered silicon nanoparticles. The new anodes will allow batteries to reach capacities 30 to 40% higher than conventional lithium-ion batteries for more than 1000 cycles. The broader impacts/commercial potential of this project is that higher capacity lithium-ion batteries will be quickly realized in portable electronics and electric vehicles. Lithium-ion batteries have revolutionized portable communications and electric vehicle power sources, yet their materials of construction have remained essentially unchanged since the mid 1980?s. If successful, the commercialization of surface-engineered silicon nanoparticles in lithium-ion anodes would result in 30 to 40% capacity gains along with an approximately 20% drop in cost per watt. Cell phones, tablets, and laptop users could use portable devices for longer periods between charging intervals. Electric vehicles with lithium- ion batteries could increase driving ranges by 40% and improve their cost competitiveness with gasoline-powered vehicles. Electrochemical Materials has strong relationships with major specialty chemical manufacturers, battery materials providers and battery manufacturers and intends to use NSF research and development funds to commercialize their innovative capacity-enhancing anode material.