Masters Student in Chemical Engineering, admitted Spring 2021
TomKat Graduate Fellow for Translational Research
Research Advisors: Prof. Stacey Bent, Chemical Engineering, and Prof. Yi Cui, Materials Science Engineering
Year Awarded: 2021
Regulating the Electrodeposition of Lithium for Stable High Energy Density Batteries
For humanity to successfully transition from fossil fuels, the mismatch in the demand and supply of renewable energy must be addressed using reliable high energy storage systems. One promising energy storage system is the lithium metal battery (LMB), owing to the high gravimetric capacity of lithium (3860 mAh/g). The potential gain in volumetric and gravimetric energy density offered by LMBs could usurp today’s lithium-ion battery technology and revolutionize energy storage. However, the lifetime of LMBs is hindered by morphological instabilities experienced during the electrodeposition of lithium.
Some of the most common strategies for addressing the instability of LMBs focus on the lithium-electrolyte interface. While there has been significant progress in the advancement of LMBs using strategies that focus on the lithium-electrolyte interface, they remain insufficient for LMB commercialization because they do not address the instabilities associated with another important interface in the battery, the lithium-current collector interface. The growth of lithium on the current collector is strongly connected to the resulting morphology of lithium, the electrolyte contact area of lithium, and the long-term performance of an LMB. As such, it is very important to design current collectors that support stable electrodeposition of lithium and enable high performing LMBs.
To control the electrodeposition of lithium metal, we introduce a novel architecture in which thin films are situated between lithium and the current collector. Our films are purposely designed to possess specific chemical and electrical properties using a technique known as atomic layer deposition (ALD). By depositing conformal and reproducible films at the lithium-current collector interface using ALD, we have identified the most critical chemical and electrical properties required for stable lithium electrodeposition. Using those properties, we have assembled practical LMBs batteries with record efficiencies and electrochemical stability. We have also demonstrated that our concept is not electrolyte-dependent, further expanding our range of applications to cheaper electrolytes.
In the grand scheme, this research project contributes to the advancement of LMBs, an energy storage system with the potential to provide twice the energy density of lithium-ion batteries. Practically, this implies that we could double the driving range of electric vehicles on one full battery charge. In addition, our architecture could be extended to other equally promising alkali metal batteries like Na and Zn metal batteries to further enable humanity’s transition from fossil fuels.