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Title of the thesis: High-Voltage Cycling Stability of Nickel-Rich Electrodes for Lithium-ion Batteries

Thesis defender: Princess Stephanie Llanos
Opponent: Prof. Neil Dasgupta, University of Michigan, US
Custos: Prof. Tanja Kallio, Aalto University School of Chemical Engineering

As electric vehicles become more common, interest has grown in lithium-ion batteries (LIBs) capable of storing more energy and allowing vehicles to drive farther. This doctoral research examines high-energy density LIBs by using nickel-rich cathodes at high operating voltages, a combined approach that increases energy density at the cost of accelerated cathode material degradation.
 
This work explores the ways in which surface coatings can enhance the durability of nickel-rich cathodes. Coatings applied at different stages of electrode fabrication reduce harmful surface reactions and limit structural changes within the material. The research also examines coating formation at the atomic scale, demonstrating that the surface chemistry of the cathode strongly influences how the initial layer forms. Key coating parameters influencing performance at high voltages are identified, as well as the role of coatings in mitigating degradation.

The findings provide insights into how surface coatings may extend the lifespan of high energy LIBs and support future developments in battery electrode research and manufacturing.

Keywords: lithium-ion battery, surface coating, NMC, atomic layer deposition

Thesis available for public display 7 days prior to the defence at .