Deep understanding of degradation in lithium ion batteries through experimental and first-principles study

"The growing interests in Lithium-ion Batteries (LIBs) have significantly accelerated the development of active materials. However, the key challenge is that electrode materials suffer from degradation, which include transition metal dissolution, solid electrolyte interphase (SEI) layer formation, and mechanical fracture. To address these issues, applying an ultrathin coating onto active materials via Atomic Layer Deposition (ALD) is an efficient way. Although numerious works have been done for active material performance improvement via ALD technology, the fundamental enhancement mechanisms of ALD coating on battery performance improvement are not yet known. Therefore, this dissertation consists of four papers, which focused on the ALD coating impact on Li intercalation, metal dissolution, Li ion diffusivity and interfacial property of SEI layer via first-principles study. Paper I explained why CeO₂ coating has better performance than Al₂O₃ coating material via faster Li diffusion, facile intercalation, and less mechanical damage of coating. Paper II discovered an unexpected metal dissolution that ultrathin CeO₂ coating intensifies the Mn dissolution of LMO and it was confirmed in several ways, including ICP-OES measurement, Mn vacancy formation energy calculation, COOP analysis, PDOS analysis, and cell level performance. Paper III revealed that the ALD CeO₂ coating thickness impact on Li ion diffusivity in coated LMO is related to surface and bulk diffusion domination and phase transition of coating layers. Paper IV demonstrated that the fracture strength of inorganic components of SEI layer was higher than organic component, implying that the inorganic-organic interface can effectively block electron transport from electrolyte to anode particles to prevent futher oxidation of active materials"--Abstract, page iv.

Name thesis:degree_name

Ph. D. in Mechanical Engineering

Grantor

Missouri University of Science and Technology

Author dc:creator

• He, Yufang

• Energy Systems
• Mechanical Engineering

Repository record dc:identifier

https://scholarsmine.mst.edu/doctoral_dissertations/2832

OAI identifier oai:identifier

oai:scholarsmine.mst.edu:doctoral_dissertations-3837