SBIR Phase I: Low-cost clean one-step production of solar silicon from natural quartzite

这个小企业创新研究（SBIR）第一阶段项目的更广泛的影响/商业潜力将是将光伏组件中的硅从4美分/瓦减少到0.8美分/瓦。除了大幅降低硅的价格外，这项新技术还消除了目前硅生产中存在的安全和环境问题。降低光伏组件的总成本将改善太阳能电池的使用，从而减少化石燃料的总体消耗。此外，由于这项新技术是零直接温室气体排放，用我们的新技术取代目前的制造过程可以直接和立即对环境产生积极影响。该项目还将推动最先进的硅制造，并提供国内光伏质量硅的来源。该项目的目标是开发一种新的熔盐电解工艺，用99.7 ~ 99.9%纯度的天然石英岩（SiO₂），只需2步就能生产太阳能硅，取代目前复杂的能源密集型5步工艺。该工艺利用了最先进的熔盐成分和抑制枝晶形成和盐捕获的新机制。该工艺可以生产4-5N纯度的硅，成本为1.70美元/公斤，使用30千瓦时/公斤，副产品为纯氧，零直接温室气体（GHG）排放。4-5N的产品纯度足以用于定向凝固或直接圆孔/晶圆生产，从而使太阳级硅的成本降低2.20-2.70美元/公斤，即比现在低75-80%。通过新工艺实现的纯度是通过电化学选择，惰性阳极以避免碳阳极污染，以及固体硅产品中的低杂质溶解度来实现的。本提案中需要解决的技术问题/风险是盐捕获以实际生产致密和纯净的产品，去除更多导致载流子寿命问题的电负性杂质（P, Fe），以及利用磁流体动力学（MHD）搅拌来克服停滞的电解质浴。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

The broader impact/commercial potential of this Small Business Innovation Research (SBIR) Phase I project will be the reduction of silicon in PV modules from 4¢/W to 0.8-1¢/W. Besides considerable silicon price reduction, this novel technology removes currently presented safety and environmental concerns of silicon production. Decreasing the total PV module cost will improve access to solar cells, through which the overall consumption of fossil fuels could be reduced. Moreover, since this novel technology is zero direct GHG emission, replacing the current manufacturing processes with our new technology can positively affect the environment directly and immediately. This project will also advance the state-of-the-art in silicon manufacturing and provide a domestic source of PV quality silicon.This project aims to develop a new molten salt electrolysis process which can produce solar silicon from natural 99.7-99.9% pure quartzite (SiO₂) in just two steps, replacing a complex energy-intensive five-step process today. This process utilizes a state-of-the-art molten salt composition with a new mechanism for suppressing dendrite formation and salt trapping. This process can potentially produce silicon with 4-5N purity at $1.70/kg using 30 kWh/kg, with pure oxygen by-product and zero direct Greenhouse Gas (GHG) emissions. The 4-5N product purity would be sufficient for directional solidification or direct boule/wafer production, resulting in $2.20-2.70/kg solar-grade silicon cost, i.e., 75-80% lower than today. This purity through the novel process is achievable via electrochemical selection, an inert anode to avoid carbon anode contamination, and low impurity solubility in the solid silicon product. The technical issues/risks to be addressed in this proposal are salt trapping to practically produce dense and pure product, removing more electronegative impurities (P, Fe) that cause problems with carrier lifetimes, and utilizing magnetohydrodynamics (MHD) stirring to overcome stagnant electrolyte bath.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.