High Energy Manganese-Based Layered Oxide Cathodes for Lithium-Ion and Sodium-Ion Batteries

Vanaphuti, Panawan

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High Energy Manganese-Based Layered Oxide Cathodes for Lithium-Ion and Sodium-Ion Batteries

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Due to the growing demand of electric vehicles and grid energy storage systems, much ongoing research is focusing on the improvement of energy density of lithium-ion and sodium-ion batteries to meet the ever-increasing demands of electrical energy storage from renewable and clean energy resources. Manganese-rich layered oxides (MLO) are one of the promising cathode materials for the near future owing to the high specific capacity, low cost, and superior energy density when cycling at high voltage. Though, many challenges still remain before this material can be fully commercialized. For the first part of my Ph.D. research, lithium, manganese-rich layered oxide cathode (LMR) is selected owing to its attractively high energy density for next generation lithium-ion batteries. However, there are several limitations that need to be addressed before it can achieve widespread success such as sluggish rate capability, voltage decay, low first cycle efficiency, and short cycle life. Out of various techniques to enhance the cathode performance and tackle these longstanding problems, doping and coating are one of the desired choices due to their simplicity and feasibility. Therefore, various doping elements, both cations (Na) and anions (F, S, Cl), and coating (AlF3 and spinel) are employed to LMR particles, aiming to improve the overall cathode performance. For the second part of my Ph.D. research, alternative to Li-ion technology, cathodes for sodium-ion batteries, is being explored. The sodium-deficient P2-type manganese-based layered (P2-NMO) cathode is selected due to its high specific capacity and low-cost compositions. Still, their commercial application is hindered by the cycling-induced structural degradation and irreversible oxygen loss when cycled at high voltage leading to electrochemical performance decay. With this, P2-NMO is substituted with the tetravalent ions (Ti/Si) to enhance the cycle stability and oxygen reversibility for the application in advanced sodium-ion batteries.

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