The Woodruff School

SUMMARY

The surge in demand for solid-state electrolytes (SSEs) over traditional lithium-ion (Li-ion) batteries, owing to their superior energy density and safety, has brought Solid Composite Electrolytes (SCEs) to the forefront. SCEs merge a porous inorganic framework with a polymerizable electrolyte, offering a pathway to enhanced ionic conductivity and mechanical stability. However, the scalable commercial production of the inorganic framework remains under-researched despite significant materials engineering advancements in SCEs. Addressing this gap, I developed a scalable, novel technique for fabricating solid-state electrolyte frameworks using the nonsolvent-induced phase separation (NIPS) method, eliminating the need for thermal or mechanical processing. This innovative approach precipitates the polymer and compacts the inorganic particles by immersing a polymer-inorganic particle solution film in a nonsolvent.

My research has focused in the creation of a flexible Thin-Film Composite Electrolyte (TCE) that boasts exceptional mechanical and electrochemical properties, including an ionic conductivity of 1 × 10^-3 S·cm-1 and a Li-ion transference number of 0.83, alongside enhanced electrochemical stability up to 5.1 V. Through extensive processing-property-performance studies on Li|N811 cells, I have optimized the TCE structure for integration into batteries. Furthermore, I have pioneered a flexible 3D-structured anode using a composite of copper nanoparticles (CuNPs) and multiwalled carbon nanotubes (MWCNTs) through the NIPS method, demonstrating superior electrochemical performance. This research not only propels the development of high-performance solid-state batteries forward but also provides a scalable method for their commercial production, bridging a crucial gap in the advanced energy storage technology sector.

Looking ahead, my future work will focus on developing a highly stretchable and fatigue-resistant polymer electrolyte. By leveraging the NIPS technique, my goal is to form components of flexible lithium metal batteries equipped with this advanced stretchable polymer electrolyte technology. This ambition aims to cater to the increasing demand for flexible applications, marking a significant stride in the evolution of battery technology towards more versatile and durable energy storage solutions.

SUBJECT:	Ph.D. Proposal Presentation

BY:	Minsu Kim

TIME:	Tuesday, April 30, 2024, 10:15 a.m.

PLACE:	MRDC Building, 3515

TITLE:	PROCESS ENGINEERING FOR HIGH-ENERGY DENSITY AND HIGH-POWER LITHIUM-ION BATTERIES FOR FLEXIBLE APPLICATIONS

COMMITTEE:	Dr. SeungWoo Lee, Chair (Mechanical Engineering) Dr. Peter J. Hesketh (Mechanical Engineering) Dr. Woon Hong Yeo (Mechanical Engineering) Dr. Hailong Chen (Mechanical Engineering) Dr. Anju Toor (Materials Science and Engineering)

SUMMARY The surge in demand for solid-state electrolytes (SSEs) over traditional lithium-ion (Li-ion) batteries, owing to their superior energy density and safety, has brought Solid Composite Electrolytes (SCEs) to the forefront. SCEs merge a porous inorganic framework with a polymerizable electrolyte, offering a pathway to enhanced ionic conductivity and mechanical stability. However, the scalable commercial production of the inorganic framework remains under-researched despite significant materials engineering advancements in SCEs. Addressing this gap, I developed a scalable, novel technique for fabricating solid-state electrolyte frameworks using the nonsolvent-induced phase separation (NIPS) method, eliminating the need for thermal or mechanical processing. This innovative approach precipitates the polymer and compacts the inorganic particles by immersing a polymer-inorganic particle solution film in a nonsolvent. My research has focused in the creation of a flexible Thin-Film Composite Electrolyte (TCE) that boasts exceptional mechanical and electrochemical properties, including an ionic conductivity of 1 × 10^-3 S·cm-1 and a Li-ion transference number of 0.83, alongside enhanced electrochemical stability up to 5.1 V. Through extensive processing-property-performance studies on Li\|N811 cells, I have optimized the TCE structure for integration into batteries. Furthermore, I have pioneered a flexible 3D-structured anode using a composite of copper nanoparticles (CuNPs) and multiwalled carbon nanotubes (MWCNTs) through the NIPS method, demonstrating superior electrochemical performance. This research not only propels the development of high-performance solid-state batteries forward but also provides a scalable method for their commercial production, bridging a crucial gap in the advanced energy storage technology sector. Looking ahead, my future work will focus on developing a highly stretchable and fatigue-resistant polymer electrolyte. By leveraging the NIPS technique, my goal is to form components of flexible lithium metal batteries equipped with this advanced stretchable polymer electrolyte technology. This ambition aims to cater to the increasing demand for flexible applications, marking a significant stride in the evolution of battery technology towards more versatile and durable energy storage solutions.