UC Berkeley

The development of lithium metal solid-state batteries offers significant potential for next-generation energy storage systems, particularly in terms of energy density and operational safety. However, their commercialization is hindered by challenges such as lithium dendrite formation, which can lead to short circuits and battery failure. This dissertation aims to provide a comprehensive understanding of dendrite growth mechanisms in solid electrolytes and explores various strategies to suppress dendrite propagation. Our research investigates the role of solid-electrolyte pellet density in the performance and failure of solid-state batteries. We find that a 99.5% dense solid electrolyte transitions from a pore-percolating to a non-percolating structure, significantly improving the longevity of the battery by preventing short-circuiting under high current densities. Additionally, we explore the role of the Ag/C buffer layers in anode-free solid-state batteries, using first-principles atomistic and continuum modeling techniques. Our findings reveal that the Ag/C BL promotes uniform lithium deposition and reduces interfacial resistance, which enhances cycling stability and mitigates dendrite formation.Furthermore, we demonstrate that silver nanoparticles play a key role in suppressing dendrite growth and preventing stress-induced solid electrolyte fractures in lithium metal solid-state batteries. Through ex-situ characterization techniques such as Focused-ion beam – scanning electron microscopy and energy dispersive X-ray spectroscopy, we show that Ag nanoparticles migrate alongside Li dendrites, promoting homogeneous growth and reducing localized stress concentrations. This uniform distribution of lithium could potentially enable higher charging rates, further enhancing the performance and safety of lithium metal solid-state batteries. By combining experimental and computational approaches, this work contributes to the broader understanding of dendrite suppression in lithium metal solid-state batteries, providing insights into the optimization of solid electrolyte properties, buffer layer design, and nanoparticle incorporation. The results presented in this dissertation offer promising pathways toward the commercialization of safer, high-performance solid-state batteries.