This Small Business Innovation Research (SBIR) Phase II project aims to develop cost-effective and commercializable anode materials exhibiting large lithium storage capacity, high rate capability, and long cycle life for next generation lithium-ion batteries. Silicon-based anode materials hold great potential to meet the high energy density requirements for advanced lithium ion batteries. However, the intrinsic low electrical conductivity and huge volume change of silicon during lithium insertion and extraction lead to quick electrode failure, and thus hindering their practical applications. The proposed Si nanocomposites are expected to effectively prevent the crumbling of Si particles, maintain the integrity of the electron-conducting network, and allow the electrolyte solution to easily access the active sites. This phase II project will develop and optimize the nanocomposite compositions and related synthesis and processing procedure to accelerate industrial scale manufacturing of anode materials in the US.
The broader impact/commercial potential of this project is the development of a new anode technology capable of exploiting a dramatic improvement in lithium ion battery performance, which will speed the deployment of advanced lithium ion batteries for plug-in hybrid electric vehicles and all electric vehicles.
Silicon-based anode materials hold a promising potential to meet the requirements on energy density for advanced lithium ion batteries, however the intrinsic low electrical conductivity and huge volume change during Li insertion and extraction lead to quick electrode failure, and thus hindering their practical applications. This NSF SBIR Phase II project has developed a new strategy for preparation of Silicon-graphene-carbon nanocomposites as anode materials with high specific capacity, high rate capability, and long cycle life. The proposed Si-graphene-carbon nanocomposites featuring silicon nanoparticles homogeneously dispersed in a graphene-reinforced carbon matrix are expected to effectively prevent the crumbing of Si nanoparticles, maintain the integration of conduction network, and allow the electrolyte solution easily accessible to the active sites. Based on the earlier success in developing and evaluating such composite anode materials during Phase I program, this phase II project focus on optimization and scale-up of the synthetic procedure towards industrial scale manufacturing. All the objectives have been achieved: (1) optimizing nanocomposite compositions through rational structural design; (2) developing proper cell evaluation protocol that can be adapted for evaluating Si-based high-capacity materials; (3) addressing the process scale-up issues to enable industrial scale manufacturing. The outcome of this project is a cost-effective, scalable manufacturing technology for the production of a high capacity (up to 2,000 mAh/g) graphene-enabled silicon anode with low first-cycle irreversible capacity loss, good rate capability, and stable cycling performance. When such an anode was paired with a commercially available NMC cathode, the resultant full cell exhibited excellent capacity retention, good rate capability, and higher energy density than those based on graphite anodes, validating the superior performance of the Si-based anode technology. Three patents have been filed. Nanotek has established a spin-off company, Angstron Battery Co., to commercialize this patent-protected, high-capacity anode technology. A series of high-capacity anode materials for lithium-ion battery industry are in the sampling and evaluating stage by several potential customers.